Page 703 - Clinical Hematology_ Theory _ Procedures ( PDFDrive )

CHAPTER 32 ■ Laboratory Manual: Manual Procedures in Hematology 687

SPECIAL STAINS (continued)

Leukocyte Alkaline Phosphatase

TABLE 32.3 (LAP) Cytochemical Stain

Scoring Characteristics

3+
Cell Amount Size of

Rating (%)* Granule Stain Intensity
2+

0 None — None

1+ 50 Small Faint to moderate

2+ 50–80 Small Moderate to strong

3+ 80–100 Medium to large Strong

FIGURE 32.12 Leukocyte alkaline phosphatase (LAP) stain. Cell 4+ 100 Medium to large Brilliant
type: Granulocytes; istinguishes leukemoi reaction rom chronic

myelogenous leukemia. Description: LAP is an enzyme associate *Percent volume of cytoplasm occupied by dye precipitate.

with the specif c granules; presence o activity in icates intracellular

metabolic activity; positivity is in icate by either a ruby re color or Example:
a blue-purple color; positivity is quantitate ; 100 consecutive ban s

or segmente neutrophils are score using the ollowing criteria: 0, 50 cells with a 4 rating 200

colorless; 1, i use positivity, occasional granules; 2, i use posi- 30 cells with a 3 rating 90

tivity, mo erate numbers o granules; 3, strong positivity, numer- 20 cells with a 2 rating 40
ous granules; 4, very strong positivity, ark, con uent granules. T e otal 100 cells 330 LAP score

scores o the 100 cells are summe . Clinical conditions: Increase

leukemoi reactions in polycythemia vera, pregnancy, in ections, Reporting Results

CML blast crisis, myelof brosis. Decrease leukemoi reactions in T e normal range epen s on the type o azo ye use . I ast
chronic myelogenous leukemia, paroxysmal nocturnal hemoglo- blue RR is use , the normal range is 32 to 182. I ast violet B

binuria, some myelo ysplastic syn romes, i iopathic thrombocy- is use , the normal range is 12 to 180.

topenic purpura. (Reprinte rom An erson SC. Anderson’s Atlas

of Hematology, Phila elphia, PA: Wolters Kluwer Health/Lippincott Clinical Applications
Williams & Wilkins, 2003, with permission.) T is test is clinically most use ul in i erentiating chronic

myelogenous leukemia rom leukemoi reactions. Leukemoi

T is proce ure is requently use to istinguish between leu- reactions may result rom in ections, toxic con itions, an neo-

kemoi reactions an chronic granulocytic (myelogenous) plasms as well as miscellaneous con itions such as the treatment

leukemia. o megaloblastic anemia, acute hemorrhage, an acute hemolysis.

Peripheral bloo or bone marrow smears are f xe an Alkaline phosphatase activity can be associate with vari-

incubate in an alkaline- ye solution o naphthol AS-MX ous con itions an isor ers. Postsurgical patients experience

phosphate an ast blue RR salt or ast violet B salt. As the a rise in activity with a peak 2 to 3 ays postoperatively an a

result o phosphatase activity, naphthol AS-MX is liberate gra ual return to normal values within 1 week. Persisting ele-

an imme iately couple with a iazonium salt, orming an vation o the LAP score is strong evi ence o an active in am-

insoluble, visible pigment at the sites o phosphatase activity matory process. LAP scores are use ul in iagnosing ectopic

(Fig. 32.12). T e ollowing reactions occur at cellular sites o pregnancy an an anovulatory menstrual cycle. T e LAP score

alkaline phosphatase activity: is also use ul in i erentiating choriocarcinoma rom hy ati i-

Naphthol AS-MX phosphate-alkaline phosphatase → orm mole because the test score is normal in choriocarcinoma

naphthol AS-MX an high in cases o hy ati i orm mole.
T is proce ure in CLSI ormat is provi e on this book’s
+
Napphthol AS-MX ast blue RR salt → blue pigment companion Web site at thepoint.lww.com/ urgeon6e.

or

Naphthol AS-MX astt violet Bsalt → violet pigment ESTERASE (ALPHA-NAPHTHYL ACETATE
+
ESTERASE) IN LEUKOCYTES: CYTOCHEMICAL

Obtaining Results STAINING METHOD

o obtain the LAP activity score, the number o cells counte Principle

in each category (0 to 4+) is multiplie by the value or that Esterases are ubiquitous in nature an encompass a variety o

category. T ese scores are summe or the cumulative total i erent enzymes acting on selective substrates. In this proce-

(see able 32.3) ure, bloo or bone marrow smears or touch preparations are

(continued)