engleski

The importance of using multiplt types reagents considering to the specifity in the daily process control

The principles of the use of control reagents in tests based on indirect antiglobulin reaction are the same for both automatic and manual performance. In daily process control they are used to control the critical points of the process. That may be reagents, equipment and competence of employees. It can also be used to verify the sensitivity of the method. Knowing the characteristics of the blood group antigens on red blood cells in terms of stability, antigenicity, and then the clinical significance of the corresponding antibodies, leads us to the use of several types of control reagent. The incidence and clinical significance of anti-D antibodies are reasons of the application of anti-D control. Fy antigen instability, during storage, requires the application of ant-Fy control. The lability of the S antigen due to the effect of the solution for decontamination, which may remain in the tube system on automatic and semi-automatic systems, is the reason for the application of anti-S control reagent. The stability of Fy antigens affects primarily Neomycin sulfate which is most commonly used as a stabilizer in the medium for test erythrocytes. On the other hand, Hypochlorite is often an integral part of the solution for decontamination of tube system and can affect the stability of the S antigen. Aim was to show the importance of applying the optimally prepared control reagents for daily process control. The source material was obtained from voluntary blood donors who have positive IAT. Their plasma, according to the algorithm for immunohaematological tests, is separated from clinical use and is applicable for the preparing of control reagents. Croatian Institute of Transfusion Medicine (CITM) uses in-house technology, which provides stability, low concentration or antibody levels and low biohazards risk of control reagents. In CITM, for years we apply anti-D and anti-Fy control reagents in daily process control. More recently we also use and anti-S control reagents.The main characteristic of control reagents is their low level of antibodies. Anti-D it is about 0.05 IU / mL. The optimum concentration of anti D antibodies is achieved by correlating the NIBSC standard 95/784. Anti-Fy and anti-S titer does not exceed 1:4 in reaction with homozygous status of the corresponding antigen. The reaction at a dilution of 1:1 must be ≥ 2 +. The stability of those reagents is not less than one year on -20°C. The result of this mode of operation is reliable interpretation of test results in the screening and identification of clinically relevant antibodies. Use of controls we were able to detect weak status of Fy antigen on the test erythrocytes, insufficient calibration of manual pipettes and pipetting errors with automated system.

daily process control

DOI: 10.1111/vox.12155