Page 701 - Clinical Hematology_ Theory _ Procedures ( PDFDrive )

CHAPTER 32 ■ Laboratory Manual: Manual Procedures in Hematology 685

SPECIAL HEMATOLOGY PROCEDURES (continued)

Clinical Applications type. T e basic principle o the absorption steps in this proce-

It is important to recognize an istinguish between the vari- ure is comparable to that originally escribe by Davi sohn

ous types o malaria to properly treat the patient. reatment is in his sheep agglutinin test. Serum or plasma is absorbe with

important because plasmo ia in ect an estroy erythrocytes. both guinea pig ki ney an bee erythrocyte stroma. Guinea

pig ki ney contains only the Forssman antigen, an bee eryth-
Limitations rocytes contain only the antigen associate with in ectious

T e proce ure is te ious, an it is requently very i cult to mononucleosis. Guinea pig ki ney will absorb only heterophile

locate in ecte erythrocytes. antibo ies o the Forssman type, an bee erythrocytes will

absorb only the heterophile antibo y o in ectious mononucleo-

BIBLIOGRAPHY sis. Agglutination o horse RBCs by the absorbe patient speci-
men is in icative o a positive reaction or heterophile antibo y.

Provi e on this book’s companion Web site at http://thepoint. Tis proce ure, in CLSI ormat, is provi e on this book’s

lww.com/ urgeon6e. companion Web site at http://thepoint.lww.com/ urgeon6e.

OSMOTIC FRAGILITY OF ERYTHROCYTES:

MONOSPOT TEST (ORTHO DIAGNOSTICS, DACIE METHOD

RARITAN, NJ) Principle

Principle In the osmotic ragility test, whole bloo is a e to varying

T is proce ure is base on agglutination o horse erythrocytes concentrations o so ium chlori e solution an allowe to

by heterophile antibo y present in in ectious mononucleosis. incubate at room temperature. T e amount o hemolysis is

Because horse RBCs exhibit antigens irecte against both then etermine by examining the supernatant ui either

Forssman an in ectious mononucleosis antibo ies, a i eren- visually or with a spectrophotometer.

tial absorption o the patient’s serum is necessary to istinguish I erythrocytes are place in an isotonic solution (0.85%)

the specif c heterophile antibo y rom those o the Forssman o so ium chlori e, water molecules will pass in an out o

Incubated Os motic Fragility

100
Positive osmotic
90 fragility

80

70

Normal
% 60

s Control
i
ys 50
l
o
m
e 40
H

30

20

10

0

0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03

NaCl (M)

Control Patient

FIGURE 32.10 Osmotic ragility plot. T e solid line epicts a le -shi e curve characteristic o here itary spherocytosis.

However, other con itions such as immune hemolytic anemias characterize by increase numbers o spherocytes may

also emonstrate a positive osmotic ragility result. T e osmotic ragility test measures the in vitro lysis o re cells sus-
pen e in solutions o ecreasing osmolarity. T e re cell is reely water permeable, an thus, when re cells are place

into a hypotonic solution, water is osmotically rawn into the re cell. As the cell swells, it becomes spherical. A er the

critical volume o the cell is reache , the membrane begins to leak large molecules such as hemoglobin. T is release o

hemoglobin into the supernatant is measure spectrophotometrically. As a result o membrane loss, spherocytes have

less capacity or a itional swelling an thus are more ragile than normal re cells when place into hypotonic solu-
tion. (Pereira I, George I, Arber DA. Atlas of Peripheral Blood. Phila elphia, PA: Lippincott Williams & Wilkins, 2011.)

(continued)