remains the most frequent transfusion-transmitted viral infection; thus, the term occulthepatitis B virus infection (OBI) was introduced. OBI is simply defined as serologically undetectable hepatitis Bsurface antigen (HBsAg-ve), despite the presence of circulating HBV DNA with or without the presence of HBVantibodies.GoalTo determine the prevalence of occult hepatitis B among blood donors and evaluate the presence of HBV DNAin HBsAg negative plasma samples.Materials and MethodsIt includes 16700 samples which donated in NCTM in Ulaanbaatar in 2013. We used to “triplex” PCR assay thatincluded the detect of hepatitis B virus HBV-DNA in addition HCV-RNA and HIV1/2-RNA for whom with absenceof serological markers of infection. The studies used molecular biology methods were performed with the help ofequipment (ROCHE COBAS S 201) and technology based on Real Time PCR (pool size: 6 donation) Then wechoose HBsAg negative, DNA positive samples and determined, anti-HBc and anti-HBs by serological methods,of ELISA Wantai HBc and HBs 3.0 tests.ResultsThe 14948 samples were detected serological negative in the total of 16700 samples. PCR test results show 35(0.23%) positive by HBV-DNA 29 (82.9%) of the 35 DNA positive blood donors were alone anti-HBc positive and3 (8.6 %) were anti-HBs, anti-HBc positive. 7(17.1%) were seronegative. Of the 35 OBI cases, 28 (80%) weredetected the first time they were screened for HBV DNA while 7 (20%) gave one more HBV PCR-nonreactiveresults before detection. Callback studies we determined 2 cases were pre-HBsAg window period.Conclusion:The prevalence of HBV DNA positive in HBsAg negative blood donors is found 0.2%. HBV NAT needs eitherextreme sensitivity or to be performed on individual donations to eliminate HBV DNA-containing units.

The result of this study show that the determination rate of the first screening test of Rhesus group D antigens negativity was 1.2%, where as the confirmation analysis decreased this rate to 1.18%. Similarly, the determination rate of the Kell K-antigen positivity rate was 0.9%. where as the confirmation test decreased this rate up-to ().X5%. These result show, that it is necessary to use confirmation test in routine diagnosis of blood sub-group determination. The Rh blood group system is of considerable importance in transfusion and clinical medicine. We have determined some clinically important red cell antigens such as C,c I), E,e in 97 Rh (+) blood donors, using the monoclonal antibodies "Erithrotest-Tsoliclon", produced at the Hematology company. Russian Federation. Among these Rh (•) blood donors prevail RIR2, R1R1 .R2R2 phenotypes accounting for 36.1%, 27.X% and 11.3% respectively. Among these Rh (-) blood donors prevail rr. rr'.rr" phenotypes accounting for 74%, 16% and 4% respectively.

Background: Healthcare works are high risk of infection through occupational exposure that contact with blood and other body fluids, including infected person, uses needles, syringes, equipment or exposures to sharp instruments. The World Health Organization (WHO) estimates, approximately 66,000 health workers are infected with the hepatitis B virus (HBV) and 200-5000 workers arc infected with human immunodeficiency virus (HIV) each year due to carelessness. HBV infection is a global health problem that remains to preventive. Hepatitis B can be prevented by vaccines that are safe, available and effective. In our country, which has a high prevalence of hepatitis B virus infection, it has been concluded that the coverage of hepatitis B vaccination and the level of immunity of health workers are insufficient. Aim: To evaluate post vaccination immunity against HBV in the staff of National center for transfusion medicine Methods: 63 workers with negative surface antigen of hepatitis B (HBsAg) and absent anamnesis of infection were selected for this study. In 2019 and 2020 all 63 workers were evaluated post vaccination immunity against HBV. Analysis done by Sysmex HSCL800 that is an automated immune assay system. Results and discussion: This center was begun to conduct the vaccination of workers from 2011. Among total 63 individuals involved in this study 53 (84.1%) were vaccinated against hepatitis B and 10 (15.9%) were not vaccinated. From the vaccinated 53 workers, 47 (88,7%) have immunized (anti-H Bs > 1 Ou/ml) but 6 (11.3%) of them were not immunized (anti-HBs <1 Ou/ml).
Therefore 1(1,9%) worker of them received just first dose, 14 (26.4%) workers were injected second dose, whereas 38 (71.7%) workers were vaccinated with third dose. The study shows that 12 (85.7%) workers after second dose and 34 (89.5%) workers after third dose were immunized. Conclutions As a result of hepatitis B vaccination, 88.7% of workers of the NCTM have had immunized against HBV. The final evaluation shows that 36 (57%) of workers had stable, 17 (27%) increased, and 10(16%) decreased level of immunization than the previous year.