Pre Lab 8and 9 - quality control and ABO/Rh testing PDF

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quality control and ABO/Rh testing...

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MLS 4424 / 5524 Medical Laboratory Fundamentals Quality Control & ABO/Rh Testing PreLabActivity #8 – Meridian and Idaho Falls – Due Oct 10th Lab Activity #9 – Pocatello – Due Oct 17th 1. What is the purpose of quality control? Quality control is necessary in order to ensure that every process or steps in the procedures are performed within established limits of acceptability so that the quality requirements are fulfilled.

2. Describe the QC done on blood bank reagents and antisera. The blood bank reagents are tested first and used daily so as to ensure that they are reacting according to the manufacturer’s direction. If there is any deviation in the procedure then the blood bank needs to validate and document the changes done in the procedure. The package insert must be checked so that there aren’t any changes in the procedure. Every new batch of reagents should be checked visually for any abnormal appearance, cloudiness or turbidity. While receiving the reagents, maintenance of cold chain while shipping should be checked and then storage should be done in accordance to the manufacturer’s direction. The QC testing done should include lot number, expiration date, date of testing, interpretation of the results and the initials of the MLS performing the test. Antisera and reagent cells should be tested daily with both positive and negative reaction before running various tests. Reagent cells are observed for hemolysis and tested against single antigen. Proper storage should be done in refrigerator when they are not in use and should be brought to room temperature before using them.

3. Describe the QC done on blood bank refrigerators and centrifuges. For the refrigerators, temperature is monitored in a chart for 24 hours. Alarm system should placed so that when temperature falls above or below acceptable range then the laboratorians are alerted by the alarm. These alarm systems should also be checked periodically by simulation of high or low temperature to verify its proper functioning. For the centrifuges, RPM should be checked with a tachometer at least every six months. The time of centrifugation which includes the time of acceleration can be checked with a stopwatch. The cell buttons can be checked for its consistency. For the refrigerated

centrifuges, temperature and speed must be noted daily. Maintenance of the calibration records along with repair, tachometer readings and temperatures is also required.

4. What are the daily QC checks? The reagents are tested daily for QC to ensure they are working fine. The antisera and reagent cells are tested before performing the tests. The temperature of refrigerated centrifuge, heating blocks, waterbath and incubators are monitored and recorded daily. The thermometers also need to undergo daily QC.

5. List the possible phenotypes and genotypes of the offspring from these moms and dads: a. A x B Possible genotypes : AB, AO, BO and OO Possible phenotypes : A, B, AB, O b. B x O Possible genotypes : BO and OO Possible phenotypes : B, O c. AB x O Possible genotypes : AO, BO Possible phenotypes : A, B

6. List the three lectins used in the blood bank and define their agglutination specificity. Dolichos biflorus - specific to antigen A Ulex europaeus – specific to antigen H Iberis amara – specific to antigen M

7. List the immunodominant sugar responsible for each antigen: a. A – N-acetylgalactosamine b. B – D-galactose c. O – L-fucose

8. In your own words, describe how to perform the ABO/Rh forward and reverse blood grouping test.

Prior to the test, prepare 2-5% cell suspension of the patient cells for forward grouping and 25% cell suspension of A cells and B cells for the reverse grouping Forward Grouping: i. label 4 tubes as >A, >B, >D and D control for forward grouping and add one drop of reagent antisera to each of the tubes. Label 2 tubes as A cell and B cell for reverse grouping and add 2 drops of patient’s plasma in each tube ii. Add one drop of patient’s cell suspension to each forward grouping tubes and add one drop of A cell and B cell to assigned tubes. iii. mix the tubes gently and centrifuge for specified time iv. read the results by gently resuspending the cell button. v. grade and record each reaction and interpret the blood group accordingly.

9. Describe what would happen if you mixed Group A RBCs with Group B plasma and why. There will be agglutination of the RBCs because anti A antibody present in Group B plasma will react with A antigens present in Group A RBCs

10. Describe what would happen if you mixed Group O cells with Group AB plasma and why. There will be no agglutination because Group O cells have no antigens in its surface and Group AB plasma has no antibodies

11. List the blood type for each reaction: >A 4+

>B 4+

>D 0

D Control 0

A Cells 0

B Cells 0

Blood Type AB

4+ 0 0

0 0 4+

4+ 0 4+

0 0 0

0 4+ 4+

4+ 4+ 0

negative A positive O negative B positive

12. What is the purpose of the D control? It serves two purpose: i. in case of AB positive blood group, it serves as a control for the immediate spin phase testing which ensures that the agglutination of test RBCs is not spontaneous.

ii. for the Rhesus negative patient, it serves as a control for the AHG phase of testing and helps to detect weak reaction which otherwise may be interpreted as D negative reaction....