Sodium Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Sodium and links to relevant pages within the course.
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|Preanalytic Variable Leading to False Thrombocytopenia|
The platelet count is only as good as the sample collected. Blood samples that are collected in EDTA or sodium citrate tubes for coagulation purposes should be inverted 5 - 10 times for proper mixing of the anticoagulant and the blood. If the tube is not mixed, small fibrin clots may form, causing a falsely decreased platelet count.
|Pseudo-thrombocytopenia: Platelet Satellitism and Platelet Clumping|
Platelet satellitism and platelet clumping can cause pseudo-thrombocytopenia. Platelet satellitism was first reported in the early 1960's. It is a rare condition that occurs when an IgG antibody forms in the presence of EDTA, the anticoagulant that is used for the collection of hematology blood specimens. The IgG antibody is directed against the glycoprotein IIb/IIIa complex on the platelet membrane. As the antibody coats the platelets, the platelets rosette around segmented neutrophils, bands, and sometimes around monocytes. Antibody-coated platelets that are huddled around white cells will not be counted as platelets by automated equipment and the platelet count will be falsely decreased. If a peripheral blood smear is reviewed, platelets will be observed attached to white blood cells. The image on the right illustrates platelet satellitism with platelets adhering to a neutrophil. Platelet clumping can also occur in the presence of EDTA and the platelet count again will be falsely decreased. The count will probably be flagged by the analyzer for platelet clumps or giant platelets. If either platelet satellitism or platelet clumps are observed on the peripheral smear, the sample could be recollected using sodium citrate as the anticoagulant. Platelets can then be counted using the automated method. The platelet count from a tube that contains liquid sodium citrate will need to be corrected for the dilutional effect of the citrate; this can be accomplished by multiplying the platelet count that is obtained from the automated analyzer by 1.1.
|Function of BNP|
Once released, BNP stimulates natriuresis and diuresis. This action works against aldosterone which conserves sodium and water. BNP causes loss of sodium and water through the kidneys to relieve the ventricular wall stretch. It also increases renal blood flow and glomerular filtration rate.
|What is the function of the hormone, BNP?||View Page|
|The reactions seen in the portion of the API strip shown in the photograph, effectively rules out Escherichia coli.||View Page|
|Chemical Substances Present in CSF|
The composition of CSF has some similarities to plasma. However, most analyte reference ranges are different for CSF than they are for plasma, For example, the protein level of normal CSF is dramatically lower than that of plasma. The following table lists some of the chemicals present in CSF, and their concentrations: Chemical Level sodium 136.0 - 150.0 m Eq/L potassium 2.3 - 2.7 m Eq/L magnesium 2.4 - 3.0 m Eq/L protein 2 - 4 mg/dL (normally diffuses across blood-brain barrier) glucose 45.0 - 60.0 mg/dL calcium 2.1 - 2.7 m Eq/dL cholesterol present in small amounts creatinine 0.5 - 1.2 mg/dL lactic acid dehyrdogenase (LDH) present in small amounts phosphorus (inorganic) 1.0 - 2.0 mg/dL urea 6.0 - 16.0 mg/dL uric acid 0.5 - 3.0 mg/dL
|Testing for Ketones in the Urine|
Testing for ketone bodies is based on a nitroprusside reaction. Acetoacetic acid reacts with sodium nitroferricyanide and glycine in an alkaline medium to produce a violet-to-purple colored complex. The urine chemical reagent strip method can detect as little as 5 mg/dL acetoacetic acid in urine. It does not react with acetone unless glycine is present or B-hydroxybutyric acid. Since these two compounds are derived from acetoacetic acid, their presence can be assumed if the test for ketones is positive. Ketones are reported either as negative, small, moderate or large amounts; or negative, 1+, 2+, 3+, or 4+. In some severe cases of ketosis, it may be necessary to perform tests on serial dilutions to provide more information on the quantity of ketones present.
|Testing for Ketone Bodies|
Testing for ketone bodies is based on a nitroprusside reaction. Acetoacetic acid reacts with sodium nitroferricyanide and glycine in an alkaline medium to produce a violet-to-purple colored complex. The reagent strip method can detect as little as 5 mg/dL acetoacetic acid in urine. It does not react with acetone unless glycine is present or B-hydroxybutyric acid. Since these two compounds are derived from acetoacetic acid, their presence can be assumed if the test for ketones is positive. Ketones are reported either as negative, small, moderate or large amounts; or negative, 1+, 2+, 3+, or 4+. In some severe cases of ketosis, it may be necessary to perform tests on serial dilutions to provide more information on the quantity of ketones present.
|The reagents used in the nitroprusside reaction are: (Choose ALL of the correct answers)||View Page|
|Which two of the following crystalline elements are found in acid urine:||View Page|
|Match collection tube colors and additive type on the right with clinical usage on the left.||View Page|
|Which of the following electrolytes is most likely to be spuriously elevated in a hemolyzed specimen:||View Page|
|Which of the following additives should be used for the collection of a sample for blood gas analysis:||View Page|
|Which of the following contributes most to serum osmolality:||View Page|
|Carbon dioxide is predominately found in blood in the form of:||View Page|
|Which one of the following serum constituents is increased following strenuous exercise:||View Page|
|Sulfosalicylic Acid Test (Exton's Modification)|
There are several acids which can be used to precipitate proteins - sulfosalicylic, trichloroacetic, nitric, and acetic acids. Sulfosalicylic acid (SSA) is the most frequently used acid test because it does not require the use of heat. Exton's reagent is 5% sulfosalicylic acid in a solution of sodium sulfate. Exton (1925) found that adding sodium sulfate to the SSA causes a more uniform precipitate to be formed. To perform the SSA procedure mix equal parts of patient urine and the reagent. Rate the amount of turbidity according to the following scale:
|Mixing Study: Specimen Requirements|
The specimen drawn for a mixing study must meet the following conditions for accurate testing: A properly filled 3.2% sodium citrate tube must be collected. Proper centrifugation to create platelet-poor plasma for analysis must occur; the presence of platelet phospholipids can interfere with the mixing study if an anti-phospholipid antibody is present. Testing must be performed within 4 hours of collection.
|Denaturing Polyacrylamide Gels|
Denaturing chemicals can be added to the acrylamides during formation of polyacrylamide gels. These additives keep the solutes or molecules in a denatured state during separation. Urea denatures double-stranded DNA to single-stranded DNA. A detergent, sodium dodecyl sulfate (SDS), denatures proteins. Adding SDS with heat denatures proteins to small, similar shaped particles and coats each so that protein structures are not reformed. SDS is usually added to the gel and the protein sample. Then the mixture of protein coated fragments moves through polyacrylamide gel pores with speed similar to a mixture of DNA fragments.
|In isoelectric focusing, the basis of separation of solutes is different than the other types of electrophoresis. Which statement below correctly describes this feature of isoelectric focusing?||View Page|
|Sodium dodecyl sulfate is added to polyacrylamide gels to denature the proteins in the sample and enhance their separation.||View Page|
|Collecting Blood Specimens for Coagulation Testing|
Venous blood specimens for coagulation assays should be collected into a tube containing 3.2% buffered sodium citrate tube (blue top tube), yielding a whole blood sample with a 9:1 blood to anticoagulant ratio. Inadequate filling of the collection tube will decrease this ratio, and may affect test results.A blue top tube used for coagulation testing should be drawn before any other tubes containing additives. This includes tubes containing other anticoagulants and/or plastic serum tubes containing clot activators. A serum tube that does not contain an additive can be collected before the blue top tube.If a winged blood collection set is used in drawing a specimen for coagulation testing, a discard tube should be drawn first. The discard tube must be used to fill the blood collection tubing dead space to assure that the proper anticoagulant/blood ratio is maintained, but the discard tube does not need to be completely filled. The discard tube should be a nonadditive or a coagulation tube.If a blood specimen used for coagulation testing must be collected from an indwelling line that may contain heparin, the line should be flushed with 5 mL of saline, and the first 5 mL of blood, or 6 times the line volume (dead space volume of the catheter), be drawn off and discarded before the coagulation tube is filled.
|Which of the following statements is NOT correct?||View Page|
|What is the preferred solution for general disinfection of work surfaces in the clinical laboratory:||View Page|
|The concentration of sodium chloride in an isotonic solution is :||View Page|
|What percentage solution of sodium hypochlorite (bleach) is recommended as a routine laboratory disinfectant:||View Page|
|Which of the following would not be considered a normal part of a routine electrolyte panel:||View Page|
|Choose the anticoagulant most commonly used for hemostasis testing:||View Page|
|Periodic Acid-Schiff: Chemistry|
The Periodic Acid-Schiff (PAS) staining technique is the most widely used procedure for the demonstration of glycogen and certain glycoconjugates. The PAS reaction is a result of aldehyde groups being formed via oxidation using periodic acid. The tissue section is then incubated in a Schiff reagent (a colorless concoction of basic fuchsin, HCl, and sodium metabisulfite). The section is finally rinsed with running water, which causes the fuchsin molecules bound to the glycogen in the tissue to turn pinkish red. Hematoxylin or fast green may be used as counterstains.
|Gordon and Sweet's Silver Staining - Chemistry|
The Gordon and Sweet's silver staining method is used to demonstrate reticular fibers. This method relies on the impregnation of retic fibers with silver through oxidation and reduction. The tissue is first oxidized using potassium permanganate to enhance subsequent staining. It is then sensitized using an iron alum solution that targets and binds to the tissue element (retic fibers). The retic fibers are then impregnated by an ammoniacal silver solution that removes and replaces the sensitizer. The silver solution is reduced by 10% formalin so that a visible metallic tone highlights the retic fibers. The metallic silver is then toned and converted to metallic gold using gold chloride solution, by providing better chemical stability, fiber contrast, and clarity. Unreduced silver and excess gold are removed via a 5% hypo (sodium thiosulfate) solution. The tissue section may then be counter stained with nuclear fast red or light green.
|Verhoeff-Van Gieson (VVG) Staining - Staining Protocol|
Sample type required: Deparaffinized and rehydrated tissue section (3-5 microns) on positively (+) charged slidesPreferred fixative: 10% neutral buffered formalin (NBF)Control: Artery or skinReagentTimeTechnical NotesVerhoeff (iron) hematoxylin30 minutesMake fresh; save solution until staining is complete.The ferric chloride in this particular hematoxylin is required as a mordant. Running water washUntil solution drains clear2% ferric chloride solutionDifferentiate until black fibers are well defined and background is grayReview slides microscopically to ensure differentiation is complete.If differentiation is not complete, return to solution for 30 seconds and repeat.Running water washUntil solution drains clear5% hypo (sodium thiosulfate)1 minute Removes iodineRunning water wash1 minuteVan Gieson's solution5 minutesCounterstainPost staining procedure: Tissue section should be dehydrated with 95% and absolute alcohols followed by two changes of xylene and then coverslip.Expected results:Elastic fibers and nuclei - BlackCollagen - RedOther tissue elements - Yellow
|Phosphotungstic Acid-Hematoxylin (PTAH) Staining - Staining Protocol|
Sample type required: Deparaffinized and rehydrated tissue section (3-5 microns) on positively (+) charged slidesPreferred fixative: Zenkers; however 10% neutral buffered formalin (NBF) may be used as wellControl: Skeletal or cardiac muscleReagentTimeTechnical NotesZenker's fixative5 minutes (in heated solution)Used as both a fixative and mordant.Microwave solution for 45 seconds on high power before placing slides inside.Running water wash5 minutesEnsure that ALL traces of the reagent have been removed.Lugol's iodine 5 minutesRunning water wash5 minutesEnsure that ALL traces of the reagent have been removed. 5% hypo solution (sodium thiosulfate)1 to 2 minutesRunning water wash 10 minutes0.25% potassium permanganate5 minutesOxidizesRunning water wash 5 minutes5% oxalic acid Bleach until tissue is colorlessRunning water wash5 minutesDistilled water 3 changesDiscard solution after use.PTAH staining solutionOvernight at room temperaturePost staining procedure: Dehydrate quickly through two changes each of 95% and 100% alcohol, along with two changes of xylene, then cover-slip. Expected results:Cross striations - BlueNuclei - BlueCollagen - Red-brownElastic fibers - Purplish
|Excess silver pigments are removed in the Gordon and Sweet's silver staining procedure using which of the following?||View Page|
|Which of the following streptococcus exhibits a positive bile solubility test:||View Page|
|Disinfection & Control of C. difficile Infection|
C. difficile spores resist dessication for months and are known to persist on hard surfaces for up to five months. Spores persist even after exposure to air. Epidemic strain B1/NAP1/027 is known to hyper-sporulate, a virulence-associated characteristic of outbreak strains. Health care workers are important vectors for transmission, as they may carry the spores on their hands or clothing. Alcohol-based hand sanitizers are very effective against non-sporulating organisms but do not kill C. difficile spores or remove the organism from the hands. The CDC recommends thorough hand washing using soap and water for caregivers and family members alike.Patients with C. difficile infection (CDI) should be isolated to a single room with a bathroom or cohorted (roomed) together. Staff treating infected patients should use personal protective equipment (PPE), including at least gowns and gloves, and must wash hands after removing gloves. The use of gowns helps to prevent contamination of clothing. Surfaces should be decontaminated using a solution of 10% sodium hypochlorite (bleach), this is effective in reducing environmental contamination in hospital rooms. The CDC recommends the use of bleach for cleaning patient and staff rooms during outbreaks. Control strategies involving reinforcement of Infection control practices rather than drug restriction are more effective. These practices include:Proper education of staff members involved in care of CDI patientsBetter isolation compliance Use of glovesFrequent and thorough hand washingEnvironmental decontamination
|Electrolytes panel (Lytes)|
Blood is tested for the most important electrolytes (salts):
Carbon dioxide (CO2)Can be run on serum or plasma.
|Yellow top tubes|
Contain either acid citrate dextrose (ACD), which maintains RBC viability and may be used for HLA phenotyping, DNA, paternity testing, or lymphocyte surface markers, or:
Sodium polyanetholesulfonate (SPS) which is sometimes used to collect blood culture specimens.
|Light blue top tubes|
These tubes contain the anticoagulant sodium citrate.
They are used mostly for coagulation (clotting) studies.
They must be completely filled to assure proper ratio of anticoagulant to blood.They must be inverted immediately after filling to prevent clotting.
|Green top tubes|
Contain either sodium or lithium heparin.Used for tests requiring whole blood or plasma such as ammonia or whole blood potassium.
|Royal blue top tubes|
Contain either sodium heparin or sodium EDTA anticoagulants, or no anticoagulant.
Are used for trace element, toxicology, and nutritional studies.
|Order of Draw|
Blood collection tubes must be filled in a specific order to avoid specimen contamination from the additive in the preceding tube. The following order of draw is an accepted laboratory standard. 1. Tubes or bottles for blood cultures 2. Light-blue top tubes (sodium citrate) 3. Serum tubes (with or without clot activator) 4. Green top tubes (sodium or lithium heparin) 5. Lavender or pink top tubes (Potassium EDTA) 6. Gray (Sodium fluoride and sodium or potassium oxalate)
|Blood Collection Tubes|
Most blood collection tubes contain an additive that either accelerates clotting of the blood (clot activator) or prevents the blood from clotting (anticoagulant). A tube that contains a clot activator will produce a serum sample when the blood is separated by centrifugation and a tube that contains an anticoagulant will produce a plasma sample after centrifugation. Some tests require the use of serum, some require plasma, and other tests require anticoagulated whole blood. The table below lists the most commonly used blood collection tubes. Tube cap color Additive Function of Additive Common laboratory tests Light-blue 3.2% Sodium citrate Prevents blood from clotting by binding calcium Coagulation Red or gold (mottled or "tiger" top used with some tubes is not shown) Serum tube with or without clot activator or gel Clot activator promotes blood clotting with glass or silica particles. Gel separates serum from cells. Chemistry, serology, immunology Green Sodium or lithium heparin with or without gel Prevents clotting by inhibiting thrombin and thromboplastin Stat and routine chemistry Lavender or pink Potassium EDTA Prevents clotting by binding calcium Hematology and blood bank Gray Sodium fluoride, and sodium or potassium oxalate Fluoride inhibits glycolysis, and oxalate prevents clotting by precipitating calcium. Glucose (especially when testing will be delayed), blood alcohol, lactic acid
|A blood collection tube that has a light-blue top contains which of these anticoagulants?||View Page|
|Diluting a Specimen for Counting on a Hemocytometer|
Semen must be diluted prior to counting sperm if a hemocytometer is used. In additon to preventing overlapping of sperm cells, the diluting fluid immobilizes the sperm in the chamber to further facilitate counting.Following liquefaction (at about 30 minutes), mix the sample manually by swirling the container several times. Thorough mixing is essential for accurate counting. Calibrated automatic pipettes are used to prepare a dilution. Some laboratories may require two separate dilutions, as recommended by WHO 5th edition. Because of the viscosity of semen, the semen should be added to the diluent using a positive pressure pipettor. The dilution often used for routine sperm counts is 1:20 but the actual dilution factor will vary depending on the sperm concentration that was noted during the initial microscopic evaluation. If a high concentration of sperm are noted, a greater dilution will be necessary. For low concentrations, a minimally diluted (e.g., 1:2) specimen may be required. The appropriate dilution is determined by estimating the concentration needed to achieve a count of at least 200 spermatozoa in the area that is counted on each side of the hemocytometer.
|Procedure for Using a Winged Blood Collection Device to Collect a Specimen for Coagulation Tests|
A light-blue top tube (a blood collection tube containing 3.2% sodium citrate) that will be used for coagulation testing must be filled to completion. Under-filling the tube changes the ratio of blood to anticoagulant. This can affect the accuracy of coagulation tests that are performed using this specimen. If a winged blood collection device (butterfly) is used to collect a light-blue top tube for coagulation studies, a waste tube should be drawn first, if the coagulation tube is the first tube to be collected for patient testing. The waste tube must also be a light-blue top tube or a tube that contains no additives. This waste tube is drawn first to remove the air in the tubing of the winged collection device. Once blood flows through the tubing, the waste tube can be removed and discarded. The waste tube does not need to be completely filled. If the air is not displaced from the tubing into a waste tube, it will be drawn into the tube used for testing and cause a short-fill of the tube. Less volume of blood in the tube alters the required blood to anticoagulant ratio needed for coagulation studies.
Amorphous urates can be dissolved in dilute sodium hydroxide. Amorphous phosphates will dissolve in dilute acetic acid. In either case, the bacteria will remain.
|Commonly used Hematoxylins: Their Oxidizers and Mordants|
Alum Hematoxylins: Hematoxylin Oxidizer Mordant Gill's Sodium iodate Aluminum sulfate Delafield's Naturally Ammonium alum Mayer's Sodium iodate Potassium or ammonium alum Harris's Sodium or potassium iodate (mercuric chloride no longer used due to its' toxicity) Potassium alum Ehrlich's Naturally Potassium alum Iron Hematoxylins: Iron salts are used as both the oxidizing agent and the mordant in the following examples: Hematoxylin Oxidizer Mordant Heidenhain's Ferric ammonium sulfate Ferric ammonium sulfate Weigert's Ferric chloride Ferric chloride
|Match the following solutions with its' appropriate use.||View Page|