Cross Match Procedure in Blood Bank (Manual Method)

Written by 
Published in Microbiology
Sunday, 26 June 2016 12:26
Rate this item
(9 votes)
Sponsored Links
When the recipient’s ABO and Rh blood groups are determined, the donor blood unit that is ABO and Rh compatible is selected, and compatibility test is carried out. The purpose of compatibility test is to prevent the transfusion of incompatible red cell units and thus avoidance of hemolytic transfusion reaction in the recipient. Compatibility test detects (i) major ABO grouping error, and (ii) most clinically significant antibodies reactive against donor red cells.

There are two types of cross-match: major cross-match (testing recipient’s serum against donor’s red cells) and minor cross-match (testing donor’s serum against recipient’s red cells). However, minor cross-match is considered as less important since antibodies in donor blood unit get diluted or neutralized in recipient’s plasma. Also, if antibody screening and identification is being carried out, minor cross-matching is not essential. Therefore, only the red cells from the donor unit are tested against the recipient’s serum and the name compatibility test has replaced the term cross-matching.

For transfusion of platelets or fresh frozen plasma, cross-matching is not required. However, fresh frozen plasma should be ABO-compatible.
A full cross-matching procedure consists of:
 
  • Immediate spin cross-match at room temperature, and
  • Indirect antiglobulin test at 37°C.

IMMEDIATE SPIN CROSS MATCH
 
The purpose of this test is to detect ABO incompatibility. Equal volumes of 2% saline suspension of red cells of donor and recipient’s serum are mixed, incubated at room temperature for 5 minutes, and centrifuged. Agglutination or hemolysis indicates incompatibility.
 
Causes of False-negative Test
 
  1. A2B donor red cells and group B recipient serum.
  2. Rapid complement fixation of potent ABO antibodies with bound complement interfering with agglutination.
 
Causes of False-positive Test
 
  1. Rouleaux formation
  2. Cold-reactive antibodies: If agglutination disappears by keeping the tube at 37°C for 10 minutes, presence of cold agglutinins is confirmed.
 
INDIRECT ANTIGLOBULIN TEST
 
Saline-suspended red cells of the donor after being incubated in patient’s serum are washed in saline and antiglobulin reagent is added. Following re-centrifugation, examine for agglutination or hemolysis. This test detects most of the clinically significant IgG antibodies.

If agglutination or hemolysis is not observed in any of the above stages, donor unit is compatible with recipient’s serum. Agglutination or hemolysis at any stage is indicative of incompatibility.
 
EMERGENCY CROSS-MATCH
 
If blood is required urgently, ABO and Rh grouping are carried out by rapid slide test and immediate spin cross match (i.e. the first stage of cross match) is performed (to exclude ABO incompatibility). If the blood unit is compatible, then after issuing it, remaining stage of the cross-match is completed. If any incompatibility is detected, the concerned physician is immediately informed about the incompatibility detected.
 
ANTIBODY SCREENING AND IDENTIFICATION
 
Screening for unexpected or irregular antibodies is done during pre-transfusion testing in recipient’s serum and in donor’s blood. In this test, serum of the recipient is tested against a set of three group O screening cells of known antigenic type. If unexpected antibodies are detected, then they are identified and blood unit that lacks the corresponding antigen is selected for compatibility test.
 
REFERENCE
Lewis SM, Bain BJ, Bates I. Dacie and Lewis Practical Hematology (9th Ed). London: Churchill Livingstone, 2001.


Sponsored Links

Additional Info

Last modified on Tuesday, 25 July 2017 11:24
Facebook Google Plus Twitter LinkedIn
Dayyal Dg.

Clinical laboratory professional specialized to external quality assessment (proficiency testing) schemes for Laboratory medicine and clinical pathology. | Author/Writer/Blogger

RELATED ARTICLES

Advertisement
Advertisement

Featured

CHOLERA: CAUSES, SYMPTOMS, DIAGNOSIS AND TREATMENT

CHOLERA: CAUSES, SYMPTOMS, DIAGNOSIS AND TREATMENT

CHOLERA is a specific infectious disease that affects the lower portion of the intestine and is char...

Useful Sites

  • NCBI

    National Center for Biotechnology Information
  • LTO

    Lab Tests Online® by AACC
  • ASCP

    American Society for Clinical Pathology
  • ASM

    American Society for Microbiology
  • The Medical Library®

    Project of BioScience.pk
Advertisement

Connect With Us

Contact Us

All comments and suggestions about this web site are very welcome and a valuable source of information for us. Thanks!

Tel: +(92) 302 970 8985-6

Email: This email address is being protected from spambots. You need JavaScript enabled to view it.

Website: https://www.bioscience.pk


This website is certified by Health On the Net Foundation. Click to verify. This site complies with the HONcode standard for trustworthy health information:
verify here.

Our Sponsors

InsightGadgets.comPathLabStudyTheMedicalLibrary.orgThe Physio Club

By using BioScience.pk you agree to our use of cookies to enhance your experience on this website.