Russell County Hospital
1610 Dowell Road
Russell Springs, KY 42642
270-866-4141
DEPARTMENT:
Laboratory
POLICY/PROCEDURE TITLE
Antibody Screening - Screening Cells
POLICY/PROCEDURE NUMBER:
400-PE-BB-137
Issued: 10/5/02
Revised: 2/2/03, 5/10/06
Supercedes:
Prepared by: R. Johnson
Approved:
Reviewed:
Medical Director
Approved:
Reviewed:
Laboratory Director
__________________________________________________________________________________________________
I.
II.
POLICY/PROCEDURE. The antibody screen test is used in the detection of unexpected blood group antibodies.
In this test, the reagent red blood cells (Screening Cells I, II, and III) are combined with patient serum to allow
antigen/antibody interaction. Either bovine albumin or LISS may be used to enhance the reaction. Bovine
albumin has traditionally been used, but the use of LISS, a low ionic strength solution, reduces the ionic strength
of the test system, which promotes antibody uptake and reduces incubation time.
SPECIMEN.
A.
No special patient preparation is required before specimen collection.
B.
Collect a full red top tube serum specimen in accordance with standard laboratory technique, ensuring
patient and specimen are identified as specified in the BB specimen collection policy, PE-BB-104.
C.
Store the sample at 1-8C for at least one week after patient testing has been performed.
D.
Age of sample intended for compatibility testing:
1.
Collect sample no more than three days prior to the intended transfusion unless the patient has not
been pregnant or transfused within the preceding three months.
2.
If the patient’s transfusion or pregnancy history is uncertain, perform compatibility tests on samples
collected within three days of the intended RBC transfusions.
III. EQUIPMENT AND REAGENTS.
A.
Antibody screen cells composed of three vials of human red blood cells.
B.
LISS or bovine albumin.
C.
Anti-human globulin, anti-IgG, -C3d; polyspecific.
D.
Coombs control reagent red blood cells sensitized with IgG antibody.
E.
Do not use reagents beyond expiration date. Store at 2-8C. May be stored at room temperature (2030C) while in use.
F.
12 X 75 mm glass test tubes.
G. Normal saline.
H.
37C heat block.
I.
Automatic cell washer/centrifuge.
Page 1 of 3
Russell County Hospital
Policy/Procedure Title: Antibody Screening - Screening Cells
Policy/Procedure Number: 400-PE-BB-137
Issued: 10/5/02
Revised: 5/10/06
__________________________________________________________________________________________________
J.
Light with concave mirror or microscope to read results.
K.
Disposable BB pipettes.
IV. QUALITY CONTROL.
V.
A.
All reagents must be tested each day of use with appropriate control materials. See BB QC policy.
B.
An auto control is performed with each screen, using patient’s serum and cells. See procedure below. The
auto control tube should show no hemolysis or agglutination until after the Coomb’s control cells are added.
C.
Do not report out patient test results without valid QC results.
PROCEDURE.
A.
Label three test tubes 1, 2, 3, and 4.
B.
With a clean pipette, add two drops of the serum to be tested to each tube.
C.
For an auto-control, add one drop of a 2% suspension of the patient’s red cells to tube #4. See procedure
400-PE-BB-134.
D.
Thoroughly mix each of the bottles of screen cells by gentle inversion and by flushing of the dropper in each
bottle to ensure uniform suspensions of cells.
E.
Add one drop of cell 1 to tube 1; one drop of cell 2 to tube 2; one drop of cell 3 to tube 3.
F.
Do ONE of the following:
1.
Add two drops of LISS to each tube and mix well. Incubate in the heat block at 37C for 10-30 minutes.
2.
Add two drops of bovine albumin to each tube and mix well. Incubate in the heat block at 37C for 30
minutes.
G. Centrifuge tubes and examine supernatant for hemolysis.
H.
Completely resuspend the cells by gentle agitation. Examine for agglutination and record results.
I.
Wash the serum/cell mixture carefully with tubes full of saline a minimum of three times. Decant completely
after the last wash.
J.
Add two drops of AHG to the dry cell button in each tube.
K.
Mix well and centrifuge.
L.
Resuspend the cells by gentle agitation. Examine for agglutination and record results.
M. To all negative tests, add one drop of Coombs reagent control cells. Centrifuge, read, and record results.
VI. RESULTS.
A.
Hemolysis or agglutination in any of the screen cells indicates the presence of an antibody directed against
the corresponding antigen that is present on the cell.
Page 2 of 3
Russell County Hospital
Policy/Procedure Title: Antibody Screening - Screening Cells
Policy/Procedure Number: 400-PE-BB-137
Issued: 10/5/02
Revised: 5/10/06
__________________________________________________________________________________________________
B.
No agglutination or hemolysis of the screen cells is a negative test result and indicates the absence of an
antigen/antibody reaction.
VII. PROCEDURE NOTES.
A.
No agglutination after addition of Coombs control cells to a negative test indicates the AHG was inactivated,
neutralized, or omitted. The negative test result is invalid and the entire antibody detection test must be
repeated.
B.
Agglutination after the addition of Coombs control cells to a negative test indicates that the AHG added was
capable of reacting and the negative test result is valid.
C.
Refer all positive indirect antibody tests and positive antibody screens to CKBC for identification. If blood
products (packed cells) are ordered at the same time, send an additional request to CKBC for crossmatch
studies. Complete the CKBC Reference Laboratory Request form (CKBC-144) for Antibody Identification.
Complete the CKBC Compatibility Testing and Transfusion Record form (CKBC-102) for crossmatch
studies.
VIII. LIMITATIONS.
A.
Antibodies specific for low-incidence factors not represented on the test cells will not be detected.
B.
False-positive results may occur if antibodies to components of the preservative solution are present in the
serum tested.
C.
The ionic strength of the test system is dependent on the amount of serum used. The use of excess serum
should be avoided, as it will increase the ionic strength of the mixture.
IX. REFERENCES.
A.
AABB Standards, 17th edition, 1996.
B.
AABB Technical Manual, 13th edition, 1999.
C.
Package insert, Reagent Red Blood Cells, Surgiscreen, Raritan, NJ; Ortho-Clinical Diagnostics, rev. 8/2000.
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