Manual Test Methods Flashcards
why is a blood smear too short? and how do we fix it?
blood spread too quickly, and angle was greater than 30
so decrease angle
why would a blood smear be too long? how do we fix this?
blood spread too slowly and angle is less than 30
so increase angle
when blood smears are too thin
drop of blood too small; patient has low Hb
the malarial protocol requires:
- 4 thin smears: 2 stained & examined in outine heme; 2 unstained to go to special heme
- 4 thick smears: unstained and forwarded to special heme
samples with malarial workup require:
indication and travel history
when is a buffy coat smear made?
- white cell count too low for analysis on routine PBS (WBC morph only)
- bacteria and parasites that may have been observed/questioned on PBS
when is a cytospin differential indicated?
when the WB C count is above the reference range >5 x 10^6/L (fluid & CSF)
- this can aid in determining the cause of the increased WBC count
- mature red cells are not commented on
- PLTs not founded in CSF; this could indicate contamination (a bloody tap)
Wright-Giemsa
- methylene blue, purified azure B, eosin
- requires methanol, distilled water
- pH 6.8
- methylene blue and azure stain acidic (nucleic acids. RNA, DNA)
- eosin stains basic = hemoglobin, eosinophil, granules
- both stain neutrophil granules
- distilled water =buffer to improve contrast
May-Grunwald-Giemsa Stain
- MG = eosin, methylene blue
Giemsa = eosin, purified azure B methylene blue - requires phosphate buffer and water
- pH 6.8
- MG = cytoplasmic (does not display inclusions and nuclear detail well)
- Giemsa = nuclear stain
- combo = nuclear and cytoplasmic staining
Giemsa stain for malaria
- eosin, purified azure B, methylene blue
- requires methanol, buffered phosphate buffer
- pH 7.0-7.2
- slides fixed in methanol and air-dried
- stain in Giemsa (diluted in ph buffer) = nuclear detail
- rinse and air dry
supravital stains
- new methylene blue (retics, Heinz)
- Brilliant cresyl Blue (retics, Heinz)
- methyl violet (Heinz)
- crystal violet (H)
- brilliant green (H)
principle of supravital stains
- used to stain living and unfixed cells in vitro to demonstrate Heinz and retics
- 1:1 ratio ; inc at RT for 15mins)
Prussian Blue Iron stain
- slides incubated in HCl and potassium ferricyanide after fixing in methanol
- HCl splits ferric iron from hemosiderin
- ferric iron combines with potassium ferricyanide = blue complex
- ferritin cannot be demonstrated as it is too small
- stains counterstained w safranin to increase contrast
T or F. In Prussian Blue Iron stain, any blue around there cells is considered an artifact
T! iron deposits must be inside cells
- iron stores may be increased in: megaloblastic anemia, hemolytic, sideroblastic, ACI, leads poisoning, hemosiderosis
- decreased in IDA and PV
LAP stain increased in
leukemoid
Multiple myeloma
Hodgkin’s disease
PV
aplastic anemia
LAP stain
- higher in bands and neuts and increases in activity with inflammation
- contains naphthol phosphate, fast red violet salt, fast blue salt
- requires acetone, hematoxylin solution for counterstain
AP scores are decreased in
CML
PNH
sickle cell anemia
MDS
pH too high
- increase dissociation of methylene blue causing the stain to be too blue
- RBC stain green/blue
- neuts appear toxic
pH too low
- increased dissociation of eosin causing the stain to be very pink
- RBCs stain red-orange
- WBC nuclei will be pale
- eosin granules will be increasingly bright orange
what is a miller occular lens used for?
retic counts and malarial parasitemia levels
- sq A = larger
transudate
accumulation of fluid caused by non-inflammatory circulatory disturbance (systemic disease)
disorders that result in transudates
- congestive heart failure (fluid backs up into tissues due to bad pumping)
- liver disease (decreased albumin = decreased oncotic pressure)
- renal disease (albumin loss = decreased oncotic pressure)
- obstructive tumors (poor lymph drainage)
exudates
- accumulation of fluids caused by an inflammatory condition such as infection, malignancy, SE, or rheumatoid arthritis
- accumulation of fluid in association with vascular wall damage
lab examination of bodily fluids except CSF:
- gross appearance (spun and unspun)
- WBC count (TNC; RBC only reported if requested)
- cytospin differential (if indicated by # of WBC present)
- crystals (if ordered)
lab examination of CSF
- gross examination spun and unspun)
- cell counts (WBC & RBC)
- cytospin differential as indicated by number of WBC
how many tubes are collected for CSF collection
3-4
- numbered
- cell count is done on the last tube
- physicians may request cell count on first and last tube to see if traumatic collection (only RBC count on the first tube)
time best to do cell count on CSF sample
within 30 mins
xanthochromia
- orange/yellow colour indicating a breakdown of Hb to bilirubin after a cerebral hemorrhage
- any degree of orange/yellow in supernatant = xanthochromia
- spun appearance is used
crystal examination in bodily fluids
aliquot of sample is spun down = sediment is analyzed
increase in retics can be due to
blood loss or hemorrhage
hemolysis
hypoxia
hematinic injury
when is a manual retic done?
- present with an interference flag
- relative result >30%
- absolute result >90 x 10^9/L
when is a manual retic done?
- present with an interference flag
- relative result >30%
- absolute result >90 x 10^9/L
manual retic count
miller occular is preferred
otherwise; 500 ciunted on each side buy 2 separate techs
#retics/500 + #retics/500
keep counting on last field even if it goes over 500
describe principle of ESR
normal situations = RBCs take time to rouleaux due to zeta potential
but if inflammation = excess proteins minimize repulsion interactions so RBCs form rouleaux and fall quicker than normal
abnormally shaped RBCs ESR
decreased (slower settling)
increased number of red or white cells ESR
decreased (more crowding; thicker blood)
