Objectives: The aim of this study was to determine the prevalence of hepatitis B surface antigen (HBsAg), hepatitis B core antibodies (anti-HBc) and hepatitis B virus (HBV) DNA among a selected group of Omani blood donors. Materials and Methods: Two hundred HBsAg-negative donors were screened for anti-HBc. Those found to be positive were investigated for HBV DNA by polymerase chain reaction. HBsAg was retested on these sera following an immune complex dissociation technique. Results: HBsAg was present in 2.8% of the donors. Forty-one out of 200 (20.5%) HBsAg-negative donors were positive for anti-HBc. Eleven were positive for HBsAg after dissociation, whereas 8 gave readings just over the cutoff. HBV DNA was not detected in this group. Conclusion: Findings indicate that testing donors for HBsAg alone is not sufficient to eliminate HBV from the blood supply in Oman.

Objective: To detect hepatitis C virus (HCV) antibodies in seronegative donors by disruption of the immune complexes (ICs). Subjects and Methods: HCV antibody detection was carried out on 600 seronegative donors following an IC dissociation assay. Reverse transcription polymerase chain reaction (RT-PCR) was then performed on the positive results. Results: Nine of the 600 samples (1.5%) were positive for IC-dissociated HCV antibodies. Of the 9 only 3 antibody-positive samples had detectable HCV RNA. Conclusion: Screening for antibodies to HCV in combination with PCR appears to be the safest way to reduce the residual risk of HCV in blood transfusion.

Nucleic acid amplification tests (NAATs) are the most sensitive method for diagnosing chlamydia and gonorrhoea. We use the COBAS 4800 CT/NG combined assay (Roche Molecular Diagnostics, CA, USA), and whilst the majority of samples yield definitive results, a small proportion are reported as indeterminate. In these instances, it is usual practice to request repeat samples which delays diagnosis. This audit was twofold: first to establish the proportion of indeterminate results with current NAAT testing requiring re-sampling. Second, to determine whether a second NAAT such as Cepheid GeneXpert CT/NG assay (Cepheid, CA, USA) could be used on initial indeterminate samples to resolve indeterminate results, therefore reducing need for repeat sampling. During 2012, 144/21,931 (0.66%) samples were indeterminate for Neisseria gonorrhoeae, Chlamydia trachomatis or both, and a repeat sample was received in only 51.77% of patients with final results being delayed for more than 24 h. Over the next six months, there were 77/9472 (0.81%) indeterminate results. After an evaluation and introduction of the Cepheid assay, the number of indeterminate results fell to 9 (0.10%). Thus, use of the Cepheid assay significantly reduced indeterminate results, reduced reliance on a repeat sampling and significantly improved turnaround time, laboratory workflow and patient experience.

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