Forward and reverse grouping by Negash Alamin
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This document describes the forward and reverse blood grouping method used to determine a patient's blood type. The method involves separating a patient's blood into plasma and red blood cell components, mixing them in test tubes with known antibodies and blood cells, and observing for agglutination to identify reactions. If agglutination occurs, the corresponding antibody has detected the patient's blood type antigen. This method allows determining a patient's ABO blood group but not other minor blood types. It is routinely used in medical labs to identify a patient's blood type for transfusion compatibility testing.
Forward and reverse grouping by Negash Alamin
- 1. Title: Forward and Reverse blood grouping method Author: Negash Alamin Occupation: Clinical labscientist E-mail: [email protected] Date: August 30, 2018
- 2. Test: Forward and Reverse blood grouping Sample: Anticoagulated blood Principle: Patient’s blood components namely plasma and pellets (RBC sediments) are mixed in five different test tubes and the blood compatibility is determined. Materials: 1-Test tubes 2-Micropippette 3-Normal saline 4-Test tube rack 5-Anti-A, anti-B, and anti-D vials Procedure: 1- Collect 3-5 ml of venous blood 2- Centrifuge 5000 rpm for 5 minutes and separate the plasma 3-Wash the pellet 2xs: meaning the sedimented RBC part 4- Prepare 3-5 % cell suspension i.e. 250 microliters cell plus 5 ml normal saline Note: 3-5% of your concentrated RBC without plasma is 250 microliters of RBC concentrate mixed with 5 ml saline. 5-Prepare 5 test tubes and label 6-Add anti-A and anti-B to 1 and 2 tubes 7-Add known A and B cell concentrates to 3 and 4 8-Add one drop anti-D to test tube 5 and 1 drop of pellet to it 9- Centrifuge all tubes for 1 minute and read results for any agglutination in any tube
- 3. 10. Designate the blood type of patient according to the agglutinated tubes. Clinical significance: Forward and reverse grouping are routinely used in lab medicine to determine patient’s blood group; differently from the slide blood grouping test. If we want to conduct compatibility testing we use other three methods called rapid cross matching, emergency cross matching and standard cross matching. To determine compatibility; but in Forward and reverse grouping we determine what blood type the patient has. Whereas, in cross matching together with IAT (indirect antiglobulin test), DAT (direct antiglobulin test), & elution testing we specifically look for various antigens and antibodies in general. N.B The above picture depicts reactions in ABO blood group only. It cannot indicate Lewis, Duffy, Kidd, Lutheran or any other minor blood grouping.