Preparation and storage stability of virtual serum for antibody screening by conventional tube test and column agglutination test

Abstract

This article is a study on the topic of the antibody screening requirements when preparing negative and positive samples for testing at the transfusion science laboratory at the Faculty of Medical Technology, Rangsit University. However, there is a limitation with regard to the need for a large quantity of patient blood samples in order to separate serum, so that there is sufficient for the students to use in their practices. In addition, serum samples have the risk of infectious diseases, such as hepatitis B virus, hepatitis C virus and human immunodeficiency virus. The purpose of this research is to examine the stability of virtual serum stored at temperatures of 2 - 8 and -20 ^OC for antibody screening. Preparing a virtual serum for both negative and positive antibody screening is conducted by using chrysanthemum powder, sodium chloride, albumin, and dissolving them in distilled water, then adding yellow coloring and finally mixing until the solution is well blended. Next, the serum is divided into two equal parts and anti-D (IgG) is added to the virtual serum at a dilution ratio of 1:8 to obtain a positive result, while the virtual serum that gives a negative result will not have any anti-D (IgG). The virtual serum was then aliquoted for storage at 2 - 8 °C and -20 ^OC. The physical examination, antibody screening using a conventional tube test (CTT) and a column agglutination test (CAT) were assayed every 3 days for 27 days (day 0, 3, 6, 9, 12, 15, 18, 21, 24, and 27) and then the results were compared with the baseline (day 0). The results showed that virtual serum stored at -20 ^OC had a greater physical stability than when it was stored at 2 - 8 ^OC. The storage of virtual serum at both temperatures gave true negative and true positive results for antibody screening with CAT and CTT on the day of the testing. This study may provide a way of preparing virtual serum for antibody screening that is safe, non-infectious, and suitable for students’ laboratory practice.