Manual Methods Flashcards
PB smears need at least _ identifiers
PB smears need at least TWO identifiers: name and accession
T or F: WBC diff and RBC morph is performed on albumin smears
FALSE; only WBC diffs are performed on albumin smears
Samples with __ Hgb should dry longer to prevent water artifact
Samples with LOW Hgb (thin blood) should dry longer to prevent water artifact
For malarial studies on a PB smear, what is checked when samples is received ?
- patient history to check previous positives / abnormal results
- determine whether initial exam or follow-up of treatment
- new positive= PATHOLOGIST NOTIFIABLE
MALarial protocol requires what/ how many smears ?
- 4 thin smears; 2 stained/ unstained
- 4 thick smears; all two-drop smears, unstained
What is a buffy coat smear for ?
- a concentrated cell prep when WBC count is too low for routine
- evaluates WBC cell morph + bacteria/ parasites queried on the PB smear
Tube used for buffy coat smears
Wintrobe tube
T or F: It is acceptable if buffy coat smear has RBCs
TRUE; It is acceptable if buffy coat smear has RBCs
Which stain is used for malaria ?
Giemsa stain
Which stain is used to demonstrate iron stores in bone marrows smears ?
Prussian Blue Iron stain:
- iron deposits are inside cells; extracellular iron is considered artifacts
Wright-Giemsa Stain (Romanowsky)
- methylene blue + azure B (basic dyes) stain acidic RNA + DNA
- eosin (acidic dye) stains basic Hgb + eosinophils
Formula: WBC correction for presence of nRBC
[Automated WBC x 100] / (100 + nRBC)
Formula: Relative Retic Count
[#retics on slide 1 + #retics on slide 2]/ (500 + 500)
NOTE: up to ~500 RBCS are counted for each slide by separate techs
How is a fluid count performed when there are crystals present?
- Interfering substances requires a manual fluid cell count
- Sample can be diluted using acetic acid to lyse all RBC as only WBC are reported (unless RBC are specified on requisition)
Which of the following can be used to demonstrate heinz bodies?
a.
Prussian blue stain
b.
Brilliant green stain
c.
Wright’s stain
d.
May-Grunwald-Giemsa stain
b.
Brilliant green stain
ESR Principle
- non-specific test for inflammation (Acute Phase Reactants; APR)
- increased APR (proteins) = reduced zeta potential = RBCs stack faster
- blood settles in Westergren tubes for 1 hour
- measures distance from bottom of plasma meniscus to the sedimented RBCs (mm)
NOTE: ESR is now replaced with CRP testing