Page 688 - Clinical Hematology_ Theory _ Procedures ( PDFDrive )

672 PART 8 ■ Fundamentals of Hematological Analysis

HEMATOLOGY PROCEDURES (continued)

Clinical Applications

In most cases, leukocyte counts are only per orme manu-

ally when there are extremely low total leukocyte counts.

T e total leukocyte count in whole bloo specimens can be

ecrease or increase ue to a variety o isor ers.

Selecte quantitative leukocyte isor ers

Decrease leukocytes (leukopenia) FIGURE 32.2 T e metho o sli e examination in the leukocyte

Viral isor ers i erential count.

Ra iation- or chemotherapy-in uce leukopenia

Aplastic anemia Reagents, Supplies, and Equipment

Megaloblastic anemia 1. A manual cell counter esigne or i erential counts

Increase leukocytes (leukocytosis) 2. Microscope, immersion oil, an lens paper

Bacterial in ections Quality Control

In ammation

Leukemias raining an experience in examining immature an abnor-
mal cell morphology are essential. A set o re erence sli es

CORRECTION OF TOTAL LEUKOCYTE COUNT with establishe parameters shoul be establishe to assess

FOR NUCLEATED RED BLOOD CELLS the competence o an in ivi ual to per orm i erential an

I more than 10 nucleate erythrocytes are seen on a i - morphological i entif cation o leukocytes an erythrocytes.

erential bloo smear, the total leukocyte count shoul be Participation in a quality assurance program continues to

correcte . ocument the expertise o the hematologist in microscopy.
Questionable or abnormal smears shoul be re erre to a

Averagetotal WBC count ×100 supervisor or verif cation.
Correcte WBC =
100 + number o nucleate RRBCs/ Procedure

100 WBCsin i erential count
1. Begin the sli e examination with a correctly prepare an

staine smear (see Chapter 2 or specimen preparation).

REFERENCES 2. Focus the microscope on the 10× objective (low power).

Scan the smear to check or cell istribution, clumping, an
Henry JB (e .). Clinical Diagnosis and Management by Laboratory abnormal cells. A a rop o immersion oil an switch

Methods, Phila elphia, PA: Saun ers, 1984:1444. to the 100× (oil immersion) objective. Begin the count by

urgeon ML, Ben er J. Hematology and Coagulation Laboratory etermining a suitable area (Fig. 32.2). Exten the exami-

Manual, Corning, NY: Corning Community College Press, 1985.
nation rom the area where approximately hal o the

LEUKOCYTE DIFFERENTIAL COUNT erythrocytes are barely overlapping to an area where the

Principle erythrocytes touch each other. It is important to examine

A staine smear is examine to etermine the percentage cellular morphology and to count leukocytes in areas that
are neither too thick nor too thin. In areas that are too thick,
o each type o leukocyte present an assess the erythrocyte cellular etails such as nuclear chromatin patterns are i -

an platelet morphology. Increases in any o the normal leu- fcult to examine. In areas that are too thin, istortion o

kocyte types an the presence o immature leukocytes or cells makes it risky to i enti y a cell type.

erythrocytes in peripheral bloo are important iagnostically 3. Count the leukocytes using a tracking pattern. Each cell

in a wi e variety o in ammatory isor ers an leukemia. i entif e shoul be imme iately tallie as a neutrophil

Erythrocyte abnormalities are clinically important in various (ban ), neutrophil (segmente ), or polymorphonuclear

anemias. Platelet size irregularities are suggestive o particu- neutrophil (PMN); lymphocyte; monocyte; eosinophil;

lar thrombocyte isor ers.
or basophil. A brie leukocyte morphology re erence is

Specimen inclu e ( able 32.1); however, re er to specif c chapters in

Peripheral bloo , bone marrow, or bo y ui se iments, the text or a complete iscussion o leukocyte an eryth-

such as spinal ui , are appropriate specimens. Whole bloo rocyte cellular morphology.

smears may be ma e rom ED A-anticoagulate bloo or 4. Abnormalities o leukocytes, erythrocytes, an platelets

prepare rom ree- owing capillary bloo . Smears shoul shoul be note . Normally, 8 to 20 platelets are present in

be ma e within 1 hour o bloo collection rom ED A speci- an oil immersion f el in a properly prepare smear (where

mens store at room temperature to avoi istortion o cell the RBCs barely touch each other). A er examining at least

morphology. Unstaine smears can be store or in ef nite 10 i erent f el s, the average number o platelets can be

perio s, but staine smears gra ually a e. multiplie by a actor o 20,000 to arrive at an approximate