Hematology Flashcards
What is hematology?
the study of blood and blood-forming tissues
What are the two main division of hematology?
(1) hematology
(2) coagulation
What’s the difference between the two main division of hem.?
hematology = study of formed elements (erythrocytes, leukocytes, and thrombocytes)
coagulation = studies the process of clotting
What can CBC be used to diagnose?
anemias, leukemias, infection and other disorders
What does a CBC test result in?
- number of RBCs, WBCs, and platelets in a volume of blood
- hemoglobin concentration
- leukocyte differential (% count of each type of WBC)
What type of tube is CBC collected in?
EDTA tubes
Aside from CBC, what other hematology specimens are there?
bone marrow aspirates, cerebral spinal fluid, tint fluids and semen
What is needed in order for testing to be done on the EDTA tubes?
It needs to be well-mixed to maintain homogenous suspension for testing
What types of tubes are specimens for coagulation collected in?
sodium citrate tubes
What does EDTA do?
it prevents clotting and the preservation of the cells’ morphology
What does sodium citrate do?
It prevents clotting, which allows for clotting factors in the plasma to be analyzed
What is a pre-analytical prep done for coagulation?
- centrifuging tubes to separate plasma from cells
What are some pre-analytical prep for hematology?
checking volume and quality; clotted samples can’t be tested
loading accessioned samples onto rockers for mixing or loading onto cassettes to load on analyzers, preparing and staining peripheral blood smears/body fluids for micro analysis
and coverslipping
What are the two acceptable methods for slide preparation?
- special spreader slide mounted in a smear-making device
2. hematology slides as a single use spreader slide
What are factors that affect the quality of smear?
- age of the specimen
- slides need to be free of nicks
- ~3mm diameter drop of well mixed EDTA blood
- not letting the blood dry before spreading to reduce abnormal cell distribution and streaks
- correct and consistent technique
Can you use samples that have been stored in the fridge for longer than 24 hours to make peripheral blood smears?
No.
What’s the angle between the spreader slide and the smear slide?
30 degrees
What is the monolayer?
the portion of the blood smear where the RBC are evenly spaced
What is the Romanowsky stain?
any stain containing methylene blue and/or its products of oxidation and a halogenated fluorescein dye
What is an acid dye component?
Eosins
What does eosin dye do?
they combine with basic (eosinophilic) cell components
What are some eosinophilic components?
hemoglobin and eosinophilic granules
What are some basic dye components?
methylene blue and azures
What do basic dye components do?
They combine with acidic (basophilic) components
what are some basophilic components?
DNA, RNA and azurophilic granules and basophilic granules
What is neutrophilic?
They are the structures that are stained pink/lilac when both basic and acidic stains are taken into the cytoplasm or nuclear structures
What colour do the acidic cell components stain?
dark purple/blue
What colour do the basic cell components stain?
pink
What are the three steps in the Wright’s stain procedure?
- Fixation in methanol
- Staining
- Washing
What does methanol fixation do?
It dehydrates the cells while causing the cells to adhere to the glass slide. It also changes the refractive index of the cells and renders the cells to be more permeable to dyes
For Wright’s stain, what colour does acidic cell components get stained?
Blue
For Wright’s stain, what colour does basic cell components get stained?
red
What’s the buffer that is most commonly used for Wright’s stain?
Sorensen’s phophate buffer that has a pH of 6.8
When a Wright’s stain is too blue, what happened?
buffer’s pH is too basic, or the staining time is too long or the smear is too thick
When a Wright’s stain is too pink, what happened?
buffer’s pH is too acidic, staining time too short
When a Wright’s stain is too light, what happened?
staining time is too short, washing is too long and vigorous, improper stain to buffer ratio, old or deteriorated stain
What are some examples of automated stainers?
dip stainers, Aerospray and HEMA-TEK
How do you identify malaria?
By doing a thick and thin film preparation and Giemsa staining
What’s the difference between the thick and thin smear for malaria diagnostics?
Thick is spread by the corner of another glass slide. It is also dried for 30 minutes before staining
Thin is prepared in the usual peripheral smear way.
What is the purpose of cytocentrifuge?
It is to concentrate bacteria and/or cells from liquid specimens (CSF, synovial fluid, pleural/peritoneal/pericardial fluid)
What is the erythrocyte sedimentation rate (ESR)?
It is a screening test to detect an inflammatory response
- it is the distance (mm) that red cells fall through blood plasma per unit of time
What is done to identify species of Plasmodium parasites?
Giesmsa staining and thick and thin films
How does preparing a thick film differ from a thin film?
thick = placing blood into the centre and spreading into a small square
also requires being dried for 30 minutes before staining
