Page 689 - Clinical Hematology_ Theory _ Procedures ( PDFDrive )

CHAPTER 32 ■ Laboratory Manual: Manual Procedures in Hematology 673

HEMATOLOGY PROCEDURES (continued)

TABLE 32.1 A Comparison of Normal Leukocytes in Peripheral Blood

Segmented Band

Neutrophil Neutrophil Lymphocyte Monocyte Eosinophil Basophil

Nuclear shape Lobulated Curved Round Indented or twisted Lobulated Lobulated

Chromatin Very clumped Moderately Smooth Lacy Very clumped Very clumped

clumped

Cytoplasmic color Pink Blue, pink Light blue Gray-blue Granulated Granulated

Granules Many Many Few or absent Many Many Many

Color of granules Pink, a few blue Pink Red Dusty blue Orange Dark blue

Average percentage 56% 3% 34% 4% 2.7% 0.3%

total circulating platelet concentration. Nucleate eryth- bu y coat. I this layer o concentrate cells is remove by

rocytes are not inclu e in the total count but are note pipetting, push-we ge–type smears can subsequently be pre-

per 100 white bloo cells (WBCs). A total o at least 100 pare an staine or microscopic examination. T is tech-

leukocytes shoul be counte . Express the results as a per- nique is use ul in the per ormance o leukocyte i erential

centage o total leukocytes counte . counts on patients with extremely low total leukocyte counts

or in special testing proce ures.

Reporting Results

Re erence values, particularly the ban neutrophil percent- Specimen

age, may vary. Values or chil ren i er rom a ult re erence A reshly rawn specimen o ED A-anticoagulate whole

values. See insi e back cover or a ull iscussion o re erence bloo is nee e .

values.
Procedure

Procedure Notes 1. Centri uge the specimen o whole anticoagulate bloo

A well-ma e an well-staine smear is essential to the accu- or at least 5 minutes at 2,000 to 2,500 rpm.

racy o the i erential count. T e knowle ge an ability o 2. With a Pasteur pipette, remove most o the top plasma

the cell morphologist are critical to high-quality results. layer an iscar .

A minimum o 300 leukocytes must be within the accept- 3. T e inter ace layer along with a small amount o plasma

able working area, when the total leukocyte count is no less an a small volume o erythrocytes can then be remove

than 4 × 10 /L. T e neutrophils, monocytes, an lymphocytes using a Pasteur pipette.
9
shoul appear evenly istribute in the usable f el s o the 4. A rop o this suspension can be place on a microscope

f lm. Less than 2% o the leukocytes shoul be isrupte or sli e an a push-we ge smear prepare . Air- ry an stain.

noni entif able orms except in certain orms associate with Alternative Technique

pathological states. I a isrupte cell is clearly i entif able,

inclu e it in the i erential count. Classi y noni entif able A ref nement o the classic bu y coat technique has been

isrupte cells (smu ges or baskets) as “other,” an note them evelope or use with automate bloo smear equipment.

on the report i more than a ew are observe . In this technique, saline solution an 22% albumin are

Te bloo smear preparation techniques escribe in a e to the inter ace layer. T is enhancement pro uces bet-

Chapter 2 are commonly use in the laboratory or the prepa- ter cell separation on the peripheral smear an minimizes

ration o bloo smears. In certain circumstances, the prepa- the sprea ing arti act uring centri ugation. o a this

ration o a bu y coat peripheral bloo smear increases the enhancement to the basic technique:

accuracy o the leukocyte i erential count. 1. Procee rom step 3 above by trans erring the inter ace

layer to a isposable Wintrobe (ESR) tube. T is tube is

Preparation of Buffy Coat Smears place into a 16 × 100-mm test tube an centri uge or a

Principle minimum o 5 minutes at 2,000 rpm.

An anticoagulate specimen o whole bloo is centri uge to 2. A er centri ugation, the top plasma layer is remove with

physically separate the bloo into three layers: plasma, leu- a Pasteur pipette an iscar e . Remove approximately

kocytes an platelets, an erythrocytes. T e inter ace layer 0.03 mL o the inter ace layer an a small volume o eryth-

between the plasma an erythrocytes is re erre to as the rocytes an trans er to a 20-mL test tube or plastic vial.

(continued)