Week 12: MANUAL DIFFERENTIAL WBC COUNT

MANUAL DIFFERENTIAL WBC COUNT

PRINCIPAL (TURGEON)

● A stained smear is examined to determine the

percentage of each type of leukocyte present and

assess the erythrocyte and platelet morphology.

Peripheral blood, bone marrow, or body fluid sediments

Manual differential WBC count specimen are obtained from?

Ethylenediaminetetraacetic acid tube

manual differential blood should be collected in what container?

within 1 hour

Smears should be made how long from collection in ETA specimens?

room temperature/25 °C

what temperature should manual diff. count specimen be stored?

true

true or false: Unstained smears can be stored for indefinite periods, but stained smears gradually fade

Back-and-forth serpentine/battlement track pattern

pattern used to read WBCs

Oil immersion objective

best/preferred lens when counting WBCs

100 WBCs

Number of WBCs that are counted and classified through the use of pushdown button counters or newer computer interfaced keypads

Neutrophils

Majority of WBCs in adults are _

Lymphocytes

Majority of WBCs in children are _

SCHILLING’S HEMOGRAM

In this method, all the leukocytes (granulocytes and agranulocytes) are classified and grouped into: (according to maturity).

Polymorphonuclear neutrophils

What are these?:
○ Myelocytes (if seen, possible of cancer)
○ Metamyelocytes (if seen, possible of cancer)
○ Bands or stabs (normal in peripheral blood)
○ Segmenters

Neutrophils, Eosinophils, Basophils

Enumerate granulocytes from most to least

Lymphocytes, monocytes

Enumerate agranulocytes from most to least

Myelocytes, Metamyelocytes

Polymorphonuclear neutrophil that if seen, possible indication of cancer

Bands/stabs

Polymorphonuclear neutrophil that is normally seen in peripheral blood

Myelocytes
Metamyelocytes
Bands/stabs
Segmenters

Enumerate Polymorphonuclear neutrophil according to maturity of cells

ARNETH’S CLASSIFICATION

● In this method, Polymorphonuclear neutrophils (PMNs) are classified according to the number of lobes which their nuclei possess.

● The more lobes, the older the cells.

From Discussion:

● >5 lobes are hypersegmented neutrophils (olds cells)

● 2–5 lobes are normal lobes

HADEN’S CLASSIFICATION

This method classifies the neutrophils according to the presence of filaments. And classifies under FILAMENTED more mature vs NON-FILAMENTED cells or blast/immature cells

Filamented

more mature classification under Haden’s classification

Non-filamented

immature cells using Haden’s classification

Monocytes

have irregular cytoplasms and are sometimes vacuolated (because they phagocytes)

True

True of false: To increase accuracy, it is advisable to count at least 200 cells when the WBC count is higher than 40 x 109 /L.

● If the WBC count is 100 x 109 /L or greater, it would be more precise and accurate to count 300 or 400 cells.

Formula: (Total count / total cells counted) x 100

Poor staining

MOST COMMON ERROR IN DIFFERENTIAL WBC COUNT

Sampling error, Inadequate mixing, Poor staining, Errors in cell identification

enumerate: ERRORS IN DIFFERENTIAL WBC COUNT

(SeIm PEid)

Flow cytometry

Electronic counting WBC most common principle employed in machines

Speed of performance, Elimination of visual fatigue, Improved precision

Enumerate electronic counting advantages

nucleated RBC, unlysed RBC, cryoglobin, platelet clumping, heparin, Monoclonal CHON

ERRONEOUS RESULTS IN AUTOMATED CELL COUNTS (WBC COUNT): Causes of Suprious INCREASE

clotting of specimen, smudge cells, uremia

ERRONEOUS RESULTS IN AUTOMATED CELL COUNTS (WBC COUNT): Cause of Spurious DECREASE

(CS, SC, U)

Cryoglobin

atypical proteins in blood

Platelet clumping

occur as EDTA induced: EDTA causes platelet aggregation

● Recollection using heparin tubes

50-70%

Reference intervals for Neutrophils %

18-42%

Reference intervals for Lymphocytes %

2-11%

Reference intervals for Monocytes %

1-3%

Reference intervals for Eosinophils

0-2%

Reference intervals for Basophils

Shift to the left

Increase in young forms of cells and has 2 types: Degenerative shift to the left & Regenerative shift to the right

Degenerative shift to the left

● Increase in the number of young forms

● Cause: Normal or decreased WBC count

Regenerative shift to the left

● Increase in the number of young forms

● Cause: Increased WBC count

● Occurs mostly in cancer patients

Shift to the right

Increase in the number of old forms of cells