Subscriber Login   Users   Administrators
Integrated cloud-based solutions for clinical laboratories

Numbers Information and Courses from MediaLab, Inc.

These are the MediaLab courses that cover Numbers and links to relevant pages within the course.

Learn more about laboratory continuing education for medical technologists to earn CE credit for AMT, ASCP, NCA, and state license renewal and recertification. Or get information about laboratory safety and compliance courses that deliver cost-effective OSHA safety training and continuing education to your laboratory's employees.



Advances in Noninvasive Prenatal Testing For Down Syndrome and other Trisomies
Massively Parallel Signature Sequencing (MPSS)

MPSS is a random, sequencing technique that analyzes millions of cfDNA fragments. MPSS analyzes the level of gene expression in a specimen by totaling the number of individual messenger-RNA (mRNA) molecules that are produced by each gene. The method sequences short segments of cfDNA from the mother and the fetus and then assigns them to specific chromosomes. After comparing the number of chromosome counts to a control value of other chromosomes, any excess of a particular chromosome (eg, 21) would suggest a trisomy. In the MPSS procedure, tagged polymerase chain reaction (PCR) products produced from complementary DNA (cDNA), which is the DNA synthesized from an mRNA, are amplified so that each corresponding mRNA molecule will yield about 100,000 PCR products with unique tags. The tags are used to attach the PCR products to microbeads. Several rounds of sequence determinations are performed and a sequence pattern or signature is identified from each microbead. The process is performed in parallel with about 1 million sequence signatures produced per overall assay. Each signature sequence is then analyzed, compared with all other signatures, and all identical signatures are counted. The level of expression of any single gene is then calculated. MPSS does requires analysis of very large numbers of DNA fragments per sample (about 25 million), which could potentially limit its clinical utility.

View Page
Commercially-Available cfDNA Prenatal Tests for Aneuploidy

Currently, there are three major commercially-available cfDNA NIPTs for detection of aneuploidy:MaterniT21™Plus Test MaterniT21 PLUS test, developed and validated by Sequenom CMM, is a laboratory-developed test (LDT) that analyzes circulating cell-free DNA extracted from a maternal blood sample. This test is offered by Sequenom Center for Molecular Medicine and utilizes the MPSS technology to identify increased numbers of chromosomes. In the test, circulating cell-free DNA is purified from maternal plasma and the DNA is analyzed for chromosomal material and converted into a genomic DNA library for the determination of chromosome 21, 18, 13 and Y representation based on massively parallel DNA sequencing. The MaterniT21 Plus test has a reported performance characteristics of 99.1% sensitivity and 99.9% specificity for the detection of Down syndrome trisomy. Test results are reported as "negative" or "positive" for trisomies.Verifi™ Prenatal Test This test, offered by Verinata Health Inc., also utilizes MPSS technology. Verifi™ Prenatal Test uses a normalized chromosome value (NCV) calculation for each chromosome tested. This NCV calculation removes variation within and between sequencing to optimize the test precision. Test results are reported as “no aneuploidy detected”, “aneuploidy suspected" for borderline cases, and “aneuploidy detected” for the respective chromosome tested. The test claims to have a >99.9% sensitivity and 99.8% specificity for detection of Down syndrome. Harmony Prenatal Test™ This test is offered by Ariosa Diagnostics and utilizes directed DNA analysis sequencing of specific cell-free DNA (cfDNA) fragments using digital analysis of selected regions (DANSR). It is a laboratory-developed test that analyzes cfDNA in maternal blood. As with other cfDNA tests, the Harmony prenatal test is best performed anytime after the tenthweek of pregnancy. Using the DANSR methodology, the Harmony Prenatal Test™ analyzes sequencing results of selected, targeted genomic regions on chromosome 21 (for Down syndrome assessment). The test results will yield an assessment of the risk for trisomy 21. Using a specific algorithm, the test results are reported out as an individualized risk for each trisomy. The test claims to have a >99% sensitivity and 99% specificity for Down syndrome detection.All of the aforementioned cfDNA tests are considered laboratory-developed tests and are not FDA-approved. Moreover, it must be stressed that at this time the cfDNA tests are not considered diagnostic and a “low-risk” test result does not suggest an unaffected pregnancy while a “high-risk” test result still requires an invasive confirmatory test.In addition, all cfDNA tests are typically intended for use in women 18 years or older with a singleton pregnancy at a minimum of 10 weeks gestation and who have been determined by their physician to be at risk for fetal trisomy. Such risks include advanced maternal age, positive results of prenatal screening tests (serum and/or NT ultrasound), the presence of ultrasound soft or hard markers, previous family history of genetic disorders, or a previous affected pregnancy for fetal aneuploidy.It is important to remember that at present, invasive prenatal diagnostic tests, such as CVS and amniocentesis, should be considered the most accurate and comprehensive way to assess fetal abnormalities.

View Page

Antinuclear Antibody Testing: Methods and Pattern Interpretation
Other Unusual ANA Patterns

Unusual Speckled ANA's are not limited to the few mentioned here. Over 150 different autoantigens have been identified in SLE patients alone. When an unusual pattern is encountered remember to go back to basics, positive or negative and if positive, what major group best describes it: Homogeneous, Speckled, Nucleolar, etc..Can have various numbers and types of speckles in One or two speckles Cell cycle dependentMetaphase mitotic cells No staining in the chromosomal region Usually there is variable staining outside of the chromosomal region.Reporting Other Unusual Speckled ANA's:Report as Unusual speckled, include titer, no follow-upClinical Significance Alerts the clinician that an ANA is present Up to clinician to piece together the puzzle

View Page

Basics of Lean and Six Sigma for the Laboratory
DMAIC: Measure Phase

During the measure phase, the team will: Observe and review the current process.Measure the current process to established a baseline.The observation part is critical even for those that are involved in the process daily, since observation can often uncover errors or variations that are not obvious. Observation is also useful to eliminate bias. For example, management's perception of the workload is likely different from the perception of the employees. Observing and reviewing the process together in real-life as a team can eliminate those biases. After the team has had a chance to observe the process, it can then decide on the appropriate data to measure. Data can be either discrete or continuous. Discrete data contain distinct values. Discrete data are usually the result of counting something using whole numbers. Continuous data are data where the values can be any numeric values and not just whole numbers (eg, time, height, and temperature measurements). Here are some examples of continuous vs. discrete data that are used in the laboratory.ContinuousDiscreteAverage time from receipt to completion for stat samplesNumber of stat samples not completed within 1 hourTime between completion of stat test by the analyzer and LIS release Number of stat samples not released in LIS within 5 minutes after the test completed by analyzerTotal LIS downtimeIncidences of LIS downtime in one monthAverage wait time for outpatients prior to specimen collectionNumber of outpatients not drawn within 15 minutesAverage response time for physician to return page for critical resultThe number of critical result pages not return by the physician within one hour

View Page

Body Fluid Differential Tutorial
Viral Lymphocytes

The smear in this slide came from a patient suffering from viral meningitis. Notice the absence of neutrophils and the large numbers of lymphocytes, most of which are normal. There is much greater amount of cytoplasm in the three atypical lymphocytes grouped in the center of the image (see arrows). These atypical lymphocytes have a chromatin pattern similar to a mature lymphocyte, even though the cells have increased size.The more activated a lymphocyte becomes in response to a viral infection, the more likely it is to see nucleoli on a cytospin, especially in the pediatric population.Nucleoli alone does not make an atypical lymph malignant or leukemic. Chromatin textures and cytoplasmic volumes will be altered as well in leukemia and lymphoma.

View Page
Non-Hodgkin Lymphoma

This cytospin was prepared from a pleural fluid obtained from a patient with multiply recurrent non-Hodgkin lymphoma. The patient had repeated pleurocentesis to remove excess and to improve his quality of life while on palliative therapy.The three large mononuclear cells in the center are the lymphoma cells (blue arrows). Notice their large total and nuclear size compared to the background lymphocytes and the scant amount of basophilic cytoplasm present with the few fine cytoplasmic vacuoles. Notice also the wide range of normal and reactive cells in the background. In patients with recurrent malignant effusions, it is not uncommon to see such mixed cell populations.It is important to look for low numbers of lymphoma cells in known lymphoma patients, as they may be present in low numbers during and after therapy, rather than in the large numbers that are usually present upon initial diagnosis.

View Page

Bone Marrow Aspiration Part I: Normal Hematopoiesis and Basic Interpretive Procedures
Calculating and Reporting the Myeloid:Erythroid (M:E) Ratio

Once the bone marrow cell count is completed and recorded, the M: E ratio should be assessed. This is performed by calculating the total myeloid precursors in proportion to the total erythroid precursors. Remember that this does not use the total white blood cell tally; the myeloid cells alone are counted, excluding lymphocytes, monocytes, macrophages, plasma cells, megakaryocytes, osteoclasts, osteoblasts, and other non-myeloid cells. In most circumstances, it is quite simple to divide the myeloid total by the erythroid total to find the ratio. This is always reported as a whole number ratio, and is normally around 3:1 (reference range= 2:1 to 4:1). In some situations where the erythroid portion is increased, or the myeloid series is decreased, the M:E ratio is reversed. This would still be expressed as a whole number ratio (example: 1:2). A simple way to perform the calculation is to always divide the larger value by the smaller. Which side of the colon, the 1 is placed on, is dependent on which cell type was larger. The 1 always belongs on the side of the cell type found in lower numbers.For example:Myeloid total 120 : Erythroid total 40 M:E ratio = 120 ÷ 40 = 3 or 3:1 So, the M:E ratio is 3:1Another example:Myeloid total 30 : Erythroid total 150Divide the larger number by the smaller (notice that the placement is reversed).150 ÷ 30 = 5 So, the M:E ratio is 1:5

View Page
Responsibility of the Technologist versus Hematopathologist

Depending on the laboratory protocols and the hematopathologist's preference, the technologist's responsibilities in bone marrow aspirate processing and reviewing can vary from simply staining slides to complex tasks such as smearing, staining, counting and distributing samples based on laboratory standard protocols. While laboratory professionals may perform bone marrow differentials, it is the hematopathologist's responsibility to review, interpret, and verify those counts after evaluating all of the samples that were provided. This includes both the bone marrow aspirate and biopsy smears, as well as the flow cytometry data, if required. When differentiating and counting samples with increased numbers of blasts, the technologist may make a determination of cell line for the blasts, according to observations on a Wright or Wright-Giemsa stained slide, but the hematopathologist may modify this placement based on flow cytometry data and additional special stains.The laboratory technologist can assess cellularity, presence of megakaryocytes, and possible presence of tumor cells on the bone marrow smears. Ultimately, the hematopatholgist is responsible for interpreting the bone marrow differential results after meticulous review of all smears stained, as well as any biopsy sections available. It is also the hematopatholgist's responsibility to identify tumor cells that may be present.In laboratories that use a standard order set with sample drop off directly from bedside, it is the technologist's responsibility to split and distribute the marrow based on laboratory protocol. It is hematopathologist's responsibility to verify that standard order testing was actually sent and to add on any additional testing deemed necessary, based on clinical history and lab findings. Once you become comfortable with bone marrow morphology and more familiar with your laboratory's protocols, performing marrow differentials will become less intimidating and more of a collaboration between technologist and hematopathologist.

View Page
Rules for Bone Marrow Differentials, continued

It is important to note that not all smears will have good areas to perform a differential in the vicinity of the bone marrow fragment. When this occurs, you must keep looking on additional smears. This is one of the reasons that several smears are stained and prepared for possible review. It can take time to recognize from 10x magnification what will be countable on 50x magnification. The best tip is to be patient and do not fail to keep on looking! In fact, sometimes it may be necessary to stain additional smears/slides, if available, to obtain enough readable material. While you are checking the smears on 10x magnification for readable areas, you should take the time to evaluate and record the following: The cellularity of the bone marrow sample Presence and number of megakaryocytes Presence of tumor cells Anything else out of the ordinary, which should be noted on the report (such as evidence of hemophagocytosis, storage disease etc.).Once you have decided where to count the marrow, you will perform the differential count. Usually a 200-cell bone marrow differential is the minimum acceptable count. However, more cells may be required depending on your laboratory/pathology protocol. Remember, unlike peripheral differentials, all nucleated cells are included in the total count, including all maturation stages of the erythroid cell series.Cell counts are performed on 40 - 50x magnification with oil depending on the optics of your scope, moving up to 100x magnification with oil as needed for fine detail. Once oil is added to the smear, move systematically through your chosen area until the morphology/cellularity/stain quality is no longer acceptable, then move back to 10x power to find another good area in the vicinity of the fragment to continue your count. You may need to progress from one slide to the next to accumulate enough cells for your differential. In fact, if there is variability in cell distribution from one smear or fragment/spicule to the next, then the count should be split between more than one smear/fragment to avoid a biased final count.If there are no spicules, then the differential should be performed in any portion of the slide that demonstrates readable morphology. In pull preps and coverslip preps, this will usually be in the thin area near the edge of the smear. If differential-type (wedge) smears are available, then the usual feathered-edge area should be used. On any of these smears, be sure that you are in deep enough from the thin edge so that the numbers of stripped cells are kept at a minimum to avoid skewing the count, as some cell types are more fragile than others.The pathologist is ultimately responsible for the final sign-out and will change/adjust/return smears for recount if there is any disagreement over numbers and cell types.

View Page
Hematogone

Hematogone is a term applied to a subset of early B-lymphocytes, found in normal bone marrow, whose morphology greatly resembles that of leukemic lymphoblasts. These cells are larger than the average mature lymphocyte, have scant cytoplasm, and a fine, soft chromatin texture; however, they are not quite as immature in appearance as a true leukemic lymphoblast. Hematogones are more common in younger children but can be found in bone marrow samples of patients at any age. They tend to be found in increased numbers within the bone marrows of patients recovering from bone marrow suppression. Common causes of increased concentrations of hematogones include: viral illness, chemotherapy recovery, and immune mediated cytopenias, such as idiopathic thrombocytpenic purpura (ITP). Hematogones are also common in patients with neuroblastoma.With experience, knowledge of the patients underlying clinical condition, and the ability to review a patient's bone marrow, it is possible to distinguish hematogones from blasts. When necessary, a hematogone flow cytometry panel can be obtained to distinguish these benign cells from lymphoblasts.Notice the size of these blast-like hematogones (see red arrows). They are larger than the few background lymphocytes present in these images. Notice the fine chromatin and scant cytoplasm. They are usually found mixed in with the full range of bone marrow cellular lineages, but can cluster with other lymphocytes within the spicules.

View Page

Chemical Screening of Urine by Reagent Strip
False Positive and Negative Results

False Positives:A false positive nitrite test result may occur when a urine specimen has remained at room temperature for an extended period of time, allowing bacterial contaminants to multiply and produce measurable levels of nitrites. Interference from some medications that cause the urine to become red or orange may lead to an incorrect reading of positive for nitrite. False Negatives:False negative results may occur in urine specimens that did not remain in the bladder for the sufficient length of time needed for the bacteria to reduce a measurable quantity of nitrate to nitrite. Other reasons for false negative results include high specific gravity, ascorbic acid levels above 25mg/dL or a low pH (<6). Less frequently, the cause may be due to a lack of sufficient nitrate in the diet (green vegetables) or further reduction of nitrite to nitrogen when large numbers of bacteria are present. In patients receiving antibiotics, the metabolism of the bacteria may be inhibited which would also produce a false negative reaction.

View Page

Diabetes and the Current American Diabetes Association Guidelines
Classification of Diabetes

In 1997, the ADA also revised the classification of diabetes. The new designations are based upon the cause, not treatment, for each class of diabetes. Where numbers are used for type classification, Arabic numerals have replaced Roman numerals for greater clarity and ease. There are four clinical classes of diabetes: Type 1 Type 2 Gestational Diabetes Other

View Page

Hemoglobinopathies: Hemoglobin S Disorders
Sequestration Crisis

Sequestration crisis occurs in sickle cell disorders when large numbers of RBCs are suddenly pooled in the spleen and liver. These organs can enlarge rapidly causing pain, hypoxemia, and hypovolemic shock. Treatment of sequestration crisis may include chronic transfusion, exchange transfusion, and/or splenectomy, depending on the patient's age and the severity of the sequestration (as determined by the hemoglobin level and degree of drop in hemoglobin).

View Page

Molecular Methods in Clinical Microbiology
Prior to 1985

Once relegated to the domain of research laboratories, molecular methods for the diagnosis of infectious disease had little, if any place, in a clinical diagnostic laboratory prior to 1985. Procedurally, molecular methods were very complex and required specialized instrumentation and dedicated laboratory space. They were also susceptible, initially, to the influence of variation of technique. Although they represented valuable research tools, and were helpful as esoteric testing for unique clinical situations, their performance characteristics simply did not fit well into most clinical laboratories.Certain pathogens were logical targets for development. Organisms that were of concern for significant patient populations, were difficult to sustain in transport, and/or were difficult to cultivate and detect by traditional methods represented some of the first targets of commercially offered molecular based assays.Sexually transmitted diseases, affecting significant numbers of people, with key pathogens affected by lability in transport or poor sensitivity with traditional cultivation or antigen detection methods, were among the first targets for development.

View Page
The Key Benefits: Improved Sensitivity of Detection

There are three key benefits that molecular methods can offer, in contrast to traditional culture methods:Improved sensitivity of detectionImproved specificity of identificationReduced turnaround timeImproved sensitivity of detectionSuccessful cultivation or detection of an organism depends on many factors, including the:Ability of the organism to survive transport Fastidious nature of the organism/its ability to grow in available culture media/systems Number of organisms present in a specimen Ability of a staining/culture system to visualize/recover low numbers of organisms Sensitivity of non-culture (antigen detection) methodsOrganisms that have been shown to be very labile are difficult to cultivate even when they are present in significant numbers. The immediacy of transport, plating, and incubation are critical factors that frequently cannot be controlled in a positive direction.Even under the ideal transport conditions, some organisms may require culture media and conditions that are not routinely available in every laboratory, which reduces the likelihood of successful cultivation.

View Page
The Key Benefits: Improved Sensitivity of Detection, continued

Some organisms are present in infections in very low numbers, which may be undetectable with direct staining methods. These organisms may also prove to be difficult to recover with currently available culture methods.Although non-culture antigen methods have been developed to address some of these difficulties (examples include direct fluorescent antibody (DFA) and enzyme immunoassay (EIA) methods), the sensitivity of these methods has not always been desirable.Molecular methods offer the prospect of:Detecting nonviable organisms that did not survive transport Detecting organisms difficult/impossible to cultivate Detecting organisms present in low numbers Providing better detection capability than other non-culture methods

View Page
The Key Benefits: Reduced Turnaround Time

Organisms that are either present in very low numbers, or that possess a characteristically slow growth rate, may require an extended incubation before they are detected in culture. Amplification and/or detection of unique sequences of either DNA or RNA provide for a more timely identification. This is true whether they are applied to the specimen for direct detection, or in some cases, to culture positive specimens for culture confirmation/identification.Even for organisms that are easy to recover and identify (example: Staphylococcus aureus) various molecular methods offer the ability for either direct detection in clinical material, or more rapid identification that would greatly aid in treatment and/or clinical management decisions.

View Page
In traditional culture or antigen detection methods, the sensitivity of detection is adversely affected by which of the following? (Choose all that apply.)View Page
Why can molecular methods offer improved turnaround times over cultivation methods? (Choose all that apply.)View Page
Challenges for Implementation: Required Work Skills

In addition to instilling a consciousness about movement from one area to the next, other work skills are critical and key to obtaining accurate results:Aseptic techniquePipetting skillsAseptic technique Due to the sensitivity of molecular assays, there is little margin for error. Cross contamination from specimens with large numbers of organism/target nucleic acid can result from the slightest deviation in aseptic technique. The use of aerosol barrier pipette tips and positive displacement pipette devices go a long way in preventing aerosol contamination, but do not replace the attentiveness of the technologist during each transfer of specimen material. When working with specimens, only one specimen container should be opened at a time.Pipetting skills Although more and more assays are being introduced with pre-prepared master mixes, invariably some reagent preparation is required. This often entails the transfer of very small volumes, which leaves no margin of error during pipetting. Attentiveness to accuracy of pipetting is a must.

View Page

Normal Peripheral Blood Cells
Eosinophil Function and Lifespan

Eosinophils have a circulating half-life of approximately 18 hours and a tissue life span of at least 6 days. They are capable of locomotion and phagocytosis and can enter inflammatory sites, but do so less readily than neutrophils. In tissues the primary location for eosinophils is in the epithelial barriers to the outside world such as, lungs, skin and GI tract. They are capable of returning to the circulating blood and bone marrow after they enter the tissues. Eosinophils are active in parasitic infections and in allergic reactions such as asthma and hay fever, and may be present in great numbers in the peripheral blood during these conditions. Stress, shock, or burns may also cause an increase in this type of cell. Eosinophils modulate an allergic response by liberating substances which can neutralize mast cell and basophil products. The image on the right shows malarial ring forms, which are parasites. This patient showed an increased eosinophil count due to his parasitic infection.

View Page
Basophil Function and Lifespan

Basophils serve as mediators of inflammatory responses, especially hypersensitivity reactions. IgE binds to the membrane receptors on basophils and degranulation is initiated. The enzymes released are vasoactive, bronchorestrictive and chemotactic (especially for eosinophils), so basophils seem to play a role in inducing and maintaining allergic reactions.The granules of basophils contain histamine, heparin and peroxidase. After degranulation occurs, basophils can synthesize more granules. The release of large numbers of these granules can cause anaphylactic shock and death. Basophils circulate in the blood for a short time and make up only a small percentage (0.5%) of the cells in circulation. They do not migrate to the tissues under normal conditions but may be seen when inflammation resulting from hypersensitivity to protein, contact allergy or skin allograft rejection is present. Basophils are sometimes increased in patients with chronic myeloproliferative disorders.

View Page
Eosinophils are increased in all of the following conditions EXCEPT:View Page

Preliminary Identification of the Primary Select Agents of Bioterrorism
Location Where Organisms Naturally Occur, Disease Produced, and Mode of Transmission

These organisms can be encountered outside of a bioterrorism event and produce human disease. It's important to be familiar with the geographic areas where these organisms naturally occur and the how disease is transmitted.Bacillus anthracis: Bacillus species inhabit the soil, water, and airborne dust. Anthrax is the disease produced, which is transmitted to humans via direct contact with infected herbivorous animals. This is where the disease is primarily encountered. Anthrax is controlled in animals in the United States, so the disease is rare. In humans, most cases are cutaneous infections found in people that handle animals and animal products, including veterinarians and agricultural workers. Anthrax is consistently present in the animal population of some geographical regions, such as Iran and Pakistan, but only small numbers of animals experience the disease at any given time. Yersinia pestis: Y. pestis is found primarily in rodents, but can also be found in several animal species, such as cats, rabbits, camels, squirrels. Animal to human transmission most commonly occurs via a flea bite, causing the most common form of the disease known as the bubonic plague. Human-to-human transmission occurs by either flea bite or respiratory droplets. This causes an overwhelming disease known as pneumonic plague, which is the most likely form that would be implicated in the event of a bioterrorist attack. Human cases of the plague continue to occur in many countries, including Africa, the southwestern United States, parts of Asia, and the former Soviet Union. Francisella tularensis: Many animals, including rodents, rabbits, deer, and raccoons act as host for this organism. Humans and domesticated animals, such as horses, cattle, cats, and dogs can become infected. The infection is transmitted to domesticated animals by ticks and biting flies. Humans are most commonly infected from the bite of an infected tick or fly. Other means of infection include direct contact with the blood of infected animals when skinning game, eating contaminated meat, drinking contaminated water, or inhaling the organisms produced by aerosols. F. tularensis carries a high risk of laboratory acquired infection and documented cases of infection have occurred. Most cases of tularemia are reported in the southern and south-central United States.

View Page

Reading and Reporting Gram Stained Direct Smears
Size and Appearance of Nonbacterial Cellular Elements on Gram Stained Smears

Type of Cell Average Size Image Comments Epithelial cells 25 µm Appear pink/red on Gram stained smear. Larger than white blood cells. Have a single nucleus. They are an indication of a suboptimal or unacceptable specimen if present in large numbers in sputum specimens, tracheal or endotracheal aspirates, or in urine specimens. White blood cells 12 µm Appear pink/red on Gram stained smear. Most often, polymorphonuclear white blood cells (PMNs). White blood cells indicate inflammation and possible infection. The direct smear examination should focus within and around these cells. Hyphae/pseudohyphae Varies Appear blue on Gram stained smear. Hyphae are tubular filamentous fungal elements, which may show branching or intertwining. Pseudohyphae are multiple buds of yeast that do not detach, thereby forming chains. Yeast 7 µm Appear blue on Gram stained smear. Round to oval, often budding. About the same size as red blood cells. Generally much larger than bacteria. A few yeast may be present as normal flora in upper respiratory tract or genital tract. They may be significant if they predominate, or if budding yeast forms are seen. Red blood cells 7µm Appear red on Gram stained smear Not usually considered a significant finding.

View Page

Real-Time PCR
Microbe Detection

Because real-time PCR can amplify extremely small amounts of genetic material, it can be used to detect and identify minute numbers of microbes in a specimen or in the environment. It can even be used to detect DNA of microorganisms that are nonviable or difficult to grow in culture. Before PCR and other amplification methods, microbes had to be cultured in order to obtain enough genetic material to analyze. Thus, dead microorganisms were almost impossible to identify. Cloning for microbial DNA was the method generally used to garner genetic material from microbes that were hard to grow; this process can be extremely lengthy and time consuming. The use of PCR creates a fast and practical way to replicate microbial genetic material, whether alive or dead. PCR is also commonly used for microbial fingerprinting in outbreak investigations as a way to confirm transmission or find the outbreak source. One can look for repeats in the genetic sequences by amplifying random polymorphic DNA, yielding PCR products of various sizes. These products can then be run through an electrophoresis gel, creating a band pattern that is known as the DNA fingerprint. PCR can also be used to fingerprint an entire microbial community in lieu of a specific organism. A community fingerprint is created by amplifying a sequence that is found in all organisms of interest. Community fingerprints can be compared over time to identify stability and variations. PCR has an advantage over culture techniques due to the differences in growth requirements and growth time. With cultures, it is common to miss organisms and determine relative abundance and frequency.

View Page

Red Cell Disorders: Peripheral Blood Clues to Nonneoplastic Conditions
A 12-year-old child presents with jaundice and scleral icterus. The image to the right captures a representative section of the peripheral blood smear. Which of the following are significant findings that should be included on the report?View Page
Introduction to Red Blood Cell Morphology Reporting

After an automated complete blood count (CBC) analysis has determined that abnormal RBC morphology may be present, a well-made and well-stained peripheral blood smear should be prepared. When a peripheral blood smear is made for the purpose of evaluating RBC morphology, accurate recognition and identification of RBC morphologic abnormalities can be an invaluable aid in the diagnosis of a variety of disorders. It is important to understand that red blood cell morphology report formats tend to vary widely among laboratories. Despite the standardization of many laboratory technologies and test result formats, there are still various protocols in use in the area of red cell morphology reporting. Current methods of reporting and quantifying red cell morphology include descriptive terms such as 'rare,' 'occasional,' 'many,' 'slight,' or 'moderate,' as well as numerical gradings of 1+, 2+, 3+, etc. Regardless of the terminology used, consistency is of greater importance. There must be a defined, semi-quantitative scheme that dictates how many cells with a specific morphologic abnormality qualify as "rare" or "many," and so on. The report format must be clear and useful to the physician. Some morphologic abnormalities are quite specific and diagnostic, but others are ambiguous and of little diagnostic significance.A well-defined, semi-quantitative report format for RBC morphology should be based on clinical significance. Some morphologic abnormalities are significant, even when they occur in very low numbers. These include:SchistocytesSickle cellsAcanthocytesSpherocytesTeardrop cellsPolychromatophilic cells Other morphologic abnormalities are significant only when seen in considerable numbers. These include:MacrocytesMicrocytesOvalocytesBurr cells (echinocytes)Target cellsStomatocytesHypochromic cells A final category includes morphologic abnormalities that do not need to be quantified as it serves no purpose; these findings can be noted as "present." These include RBC agglutinationRouleauxDimorphic or double red cell populationAn example of a standardized reporting format is given on the following page.

View Page
This oil immersion field (1000x) is representative of the peripheral blood smear. Which report is the most appropriate for documentation of the finding of teardrop cells using the Guidelines for Standard Reports that were described on the previous pages and included as a PDF in this question?View Page

Risk Management in the Clinical Laboratory
Safe Medical Devices Act of 1990 (SMDA)

The Safe Medical Devices Act of 1990 requires user facilities (e.g., hospitals, nursing homes) to report suspected medical device-related deaths to both the FDA and the manufacturers. Medical device-related serious injuries must be reported to the manufacturer. However, if the medical device manufacturer is unknown, the serious injury is reported by the facility to the FDA. Laboratory personnel should familiarize themselves with their institution's procedures for reporting adverse events to the FDA.Medical devices that are included in this reporting requirement (if they may have caused serious injury to a patient or patient death) are laboratory instruments, reagents, or devices used during phlebotomy procedures. If it appears that a device has caused injury, it is important that the device and packaging be saved and any serial or lot numbers noted. An incident report should be completed within 24 hours. The incident report must then be handled by the institution's "Risk Management" department (if applicable), who will file the necessary reports.

View Page


MediaLab, Inc.

http://www.MediaLabInc.net    |    (877) 776-8460 (tollfree)    |    sales@medialabinc.net