Rack Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Rack and links to relevant pages within the course.
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|Manual Staining of Bone Marrow Preparations: Wright's and Wright-Giemsa Stain|
Wright's or Wright-Giemsa stains are usually the preferred staining method for bone marrow aspirate smears. These are methanol-based staining solutions with similar dye composition to the diff-quick stain but require longer stain contact time for adequate staining. The Wright's and Wright-Giemsa stains have a buffer step as well. Since Wright's stains are methanol based they do not require a fixation step prior to staining, although you might prefer to do so first to reduce water artifact that can occur on humid days or with aged stain.In the dip method of staining, the smears are first dipped in methanol to fix the specimens and then placed in Wright's or Wright-Geimsa stain for 10-15 minutes to stain. The smears are next moved to a mixture of stain and 6.8 pH phosphate buffer (usually one part stain to 2-3 parts buffer) and allowed to stain for at 20-30 minutes. After staining, they are given a quick rinse in distilled water and allowed to air dry before mounting or cover-slipping.When using a staining rack, the marrow slides or coverslips are first flooded with enough stain to cover the slide and stained for 10-15 minutes. Then, a 6.8 pH buffer is carefully added without overflowing and gently mixed by blowing until a green metallic sheen forms. This is allowed to stand for 20-30 minutes and then rinsed off with distilled water. The slides or coverslips are then air dried and mounted.Staining times can be extended for extremely cellular marrows; however, care must be taken when using the rack staining method. Extended times can lead to evaporation of the stain and cause excessive precipitation. Both the stain and buffer can be topped up if necessary to prevent this from occuring, while additional rinse time may be needed.Wright's and Wright-Giemsa stains, when performed properly, give sharp and clear nuclear, cytoplasmic, and granule detail. There can be variation in the quality of the stain from batch to batch, dependent on the manufacturer's quality control, storage, and shipping conditions. Many manufacturers age their stains for a minimal amount of time before shipping and assume that there will be additional standing time at the distributor before it reaches your lab. This may work for peripheral blood staining, but it is not ideal for bone marrow staining. It is advisable, if possible, to keep a separate stock of Wright's stain for bone marrow staining which is kept at least 6 months before use. Like a fine wine, the older Wright's stain gets, the better the quality and clarity of the final stain.
The procedure your laboratory utilizes for bone marrow stains is determined by the type of stainer available to you. The stainer available may also dictate the type of smear preparations that your laboratory makes. There are several types of automated hematology stainers on the market today. Some stainers are simple continuous-feed stainers with limited programmability. Some are batch stainers that can have multiple programs, customizable to the sample type or stain preference of the user. Other stainers are dip stainers that automatically move a slide rack from bucket to bucket, or an inline corkscrew that moves slides down a platen and dispenses stain/solutions at fixed positions. Finally, there are centrifuge stainers that apply stains to a spinning slide tray during programmed intervals.Hema-tek® stainers, with a fixed stain area, require shorter preparations on long slides, so slide pull preps or differential smears would be the laboratory standard. Since the stain time and volume is fixed, bone marrow slides may need to be stained twice and sometimes even three times for extremely cellular bone marrows. When using this type of stainer, always check the stain quality before coverslipping.Automated dipping stainers can be used with either long slides or coverslips,when utilizing a coverslip basket, so the choice of smear type is driven by laboratory and pathologist preference. As with manual staining times, the laboratory should have a separate program for bone marrow staining that reflects the need for longer contact times. Wescor® hematology stainers are quite flexible. They are centrifugal stainers that are pre-programmed for rapid, Wright-Giemsa and May-Grunwald stains, as well as having programmable custom settings. Each stain type can be adjusted for color balance and intensity. They can be used with slides or coverslips when coverslip adapters are utilized. Since it is a centrifugal staining system, stain precipitate is minimized and it is very easy to change programs as you shift from peripheral bloods to fluids cytospins to bone marrows.
|Processing Filter Cards after Collecton|
Once the required circles on the filter card have been completely saturated with blood and the care of the infant is complete, all necessary patient demographic information on the card must be completed.Every item included in the demographic section must be completed accurately. The age of the infant is important and is often recorded in hours and/or days. Contact information for the parent or guardian as well as the primary care giver is also important so that this information can be used by public health officials to initiate and track the follow-up treatment for the patient. When completing the demographic section of the card, it is advisable to use a ball point pen. Soft or felt tip pens can be absorbed by the filter paper and can possibly affect the test results.Cards should be allowed to air dry completely. Never stack cards in such a way that will allow the blood drops of the cards to come in contact with each other. This could result in transfer of one patient's blood to another patient's card. Many facilities have special racks in which to place cards while drying to avoid the contamination of specimens. After the cards are dry, they should be delivered in a timely manner to the state testing facility.
Most hemoglobins are soluble in a high-molarity phosphate buffer; hemoglobin S is not. The buffer is made of of dibasic and monobasic potassium phophates, Saponin and dithionate. Kits are available, which consist of this reagent, pipets and a reading rack. A 1:100 dilution of blood into buffer is made, incubated for 5 minutes, and turbidity is observed against a white background with black lines.A positive result (A below) is indicated by a turbid solution. A negative result (B below) is obtained when lines are visible through the solution.The solubility test should only be used as a screening test as it is not reliable for diagnosing sickle cell disease.
Pam is seated at the workbench where she routinely prepares dilutions using an automated pipette. She leans to the right and stretches over her rack of tubes each time she needs to change a pipette tip. Pam is working in an awkward body position because the pipettes are not in a convenient location and the space is not well organized.By changing the location of the pipettes to within her routine work area, she can avoid overstretching to reach the pipettes and avoid contorting her body into an awkward position that could eventually result in an MSD. As shown in the image, regularly used items should be close to the worker to avoid leaning forward and over-extending reach radius. Adjust your work space so that you can reach tools and equipment without unusual bending or twisting; arrange the work area properly within the "work zone".Avoid reaching more than 10 inches (25 cm) in front of the body for frequently used materials or 20 inches (50 cm) for items that are used occasionally.
|The dematiaceous fungus that may produce both acrotheca and rhinocladiella types of sporulation is:||View Page|