Manual Methods—Bench Questions Flashcards by Samantha Boyer

WBC dilution

1:20
3% acetic acid
1.9 mL + 100 uL

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procedure for WBC estimate

average WBCs in 1/4 field on 10x

manual count if >20% discrepancy from analyzer

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WBC correction for NRBCs

wbc(100)/(nrbc + 100) = corrected wbc

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how closely should sides on hemacytometer match?

<25 cells: ±5 cells
>25 cells: within 20%

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normal wbc ranges for adult and newborn

adult: 4.3-10.0
newborn: 5.0-30.0

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causes of increased wbc

infection
leukemia
pregnancy
exercise

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causes of decreased wbc

chemo
viral infection
myelodysplastic syndrome

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plt dilution

1:100
ammonium oxalate

lyses rbcs, but not retics

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area to count for plts

<200: 1 large square
>200: 5 small squares

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normal plt
critical plt

normal: 140-400
critical low: <30
critical high: >800

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plt estimate procedure

average plts on 100x * 15 and 20 to give range value should fall in

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why isn’t MPV calculated from manual count?

no way to calculate; derived from plt histogram

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increased MPV

younger plts being released; thrombocytopenia

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causes of thrombocytopenia

ITP
HIT
DIC
TTP
ALL
aplasic anemia

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causes of thrombocytosis

IDA
CML
essential thrombocytosis

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normal retic adult and newborn

adult: 0.5-2.0%
newborn: 2.5-6.5%

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main causes of elevated retic

hemolytic anemia
blood loss
thalassemia
response to therapy for anemia

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Miller Ocular calculation

cells counted out of 112/10 = %

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corrected retic takes into account…

calculation

smaller pool of rbcs in pts with low hct

corrected retic = retics(hct/45)

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retic index takes into account…

calculation

premature release of retics during anemia

retic index = [retics(hct/45)]/maturation time

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shift/stress retic

retics released early when H&H are low to compensate

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principle of sickle solubility

saponin lyses rbcs
Na hydrosulfite reduces released Hgb
reduced Hgb S is insoluble in phosphate buffer, so suspension is cloudy

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—–% sickling Hgb must be present for positive sickledex

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sickling hemoglobins other than Hgb S

Bart
C Harlem
C Georgetown

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Hgb S mutation

Chromosome 11 glutamic acid replaced by valine

Hgb S disease & trait on electrophoresis

- disease: mostly Hgb S, some F and A2 - trait: 60% Hgb A, 40% Hgb S, small amount of F and A2

possible causes for false negative sickledex (2)

- pt too young, <10% Hgb S - total Hgb <8 g/dL

sickledex procedure if Hgb <8

add 40 uL, not 20

seen on smear of sickle disease & trait

- disease: sickles, targets, nrbcs, HJ bodies, pappenheimers, poly - trait: targets

best sample for OF test

Na heparin

why are OF samples incubated 24 hours?

detect subtle abnormalities in OF that would not show up immediately

normal beginning and ending OF hemolysis values

begins at 0.45% ends at 0.35%

HS rbc defect

spectrin membrane defect

why do thal pts have ↓ OF?

targets and hypos can take in more water before lysing

procedure for making KB control slides

- negative control: normal male blood - 1:20: 1 drop cord + 19 drops male blood - 1:10: 1 drop cord + 9 drops male blood 6 drops saline + 4 drops control blood; make 20 thin slides

reasons for performing KB

- determine necessary RhIg dose - check for thalassemia (moth-eaten HgbF distribution) - check for hereditary persistence of Hgb F

methodology of monospot

latex particles or rbcs coated with Ag specific to heterophile Ab in dipstick dipstick is immunochromatographic

samples for monospot

serum preferred EDTA plasma acceptable if tested within 24 hours

is monospot specific for infectious mono?

yes

seen on smear of EBV pt

atypical lymphs, often >20%

sx of EBV and other infections that cause similar sx

fever, malaise, sore throat, lymphadenopathy CMV toxoplasma

can cause false negative monospot

children <12yo and 10-20% of adults

reflex for negative monospot

EBV serology if negative, CMV serology

normal CSF rbc and wbc for adult and newborn

**WBC** adult: 0-10 baby: 0-30 **RBC** 0 for both

tube order for CSF

1. chemistry 2. micro 3. hematology

distinguish bloody tap from hemorrhage

- distribution of blood in tubes - macrophages with hemosiderin/rbcs - clot formation(tap) - xanthochromic

causes of xanthochromia

- rbc degradation - bilirubin - increased protein - melanoma pigment

lining cells seen in CSF

- ependymal - choroid plexus

bacterial infection CSF effects on glucose, protein

↓ glucose ↑ protein

corrective action for nrbcs found in CSF

WBC correction formula

what do we do with CSF of ALL children?

look at cytospin smear regardless of WBC count, to check for blasts

cause for a BF to be rejected for count

clot

lining cells

- mesothelials (serous) - synoviocytes (joint) - ependymal/choroid plexus (csf) - epithelials (amniotic)

synovial fluid cannot be diluted with...

acetic acid (clot)

components of semen analysis and normal values (8)

- pH: 7-8 - count: >20 mil/mL - motility: >50% motile - liquefaction: liquefied - viscosity: not viscous - volume: 1.5-5 mL - morphology: <30% abnormal - vitality: 3+ to 4+

no sperm procedure

azospermia fructose test; check for bilateral aplasia of seminal vesicles or obstruction of ejaculatory ducts

sites for BM collection

- posterior iliac crest (adult) - tibia (child)

BM aspirate used for...

- cytogenetics - flow - molecular - cultures

BM core biopsy used for...

- architecture - cellularity

handling for each type of BM test

- aspirate smear (EDTA, bedside) - flow (Na hep) - genetics (Na hep) - PCR (EDTA) - culture (SPS, or Na cit for viral) - biopsy (sent to histology in jar of fixative)

BM diff procedure

- count every other field - count 200 cells (100/slide) - differentiate nrbcs - assess cellularity, megakaryocyte, presence of malignants, M:E ratio

normal BM diffs show...

pyramid form of full range of maturation ME: 2:1 to 4:1 normal cellularity: 100-pts age, ± 10% 5-10 megakaryocytes per 10x field

2 conditions causing hypersegmented neutrophils

- megaloblastic anemia - myelodysplastic syndrome

signs of wbc dysplasia

- hyper/hyposegmented - agranular - asynchrony

signs of rbc dysplasia

- multinucleated nrbcs - fetal traits - asynchrony - karyorrhexis - ringed sideroblasts

signs of plt dysplasia

- giant - micromegakaryocytes - agranular

leukemoid rxn

- left shift - increased wbc - toxic changes

CLL on smear

lymphs smudgs high wbc

myelodysplastic syndrome on smear/bm

- dysplasia - PB cytopenia in 1+ lines - BM hypercellularity

leukoerythroblastosis associated with...

myelophthisis (crowding out)

toxic changes to neutrophils

- dohle bodies - toxic gran - vacuolization