Delays in HIV-1 infant polymerase chain reaction testing may leave children without confirmed diagnoses in the Western Cape province, South Africa

Background: Early diagnosis and confirmation of HIV infection in newborns is crucial for expedited initiation of antiretroviral therapy. Confirmatory testing must be done for all children with a reactive HIV PCR result. There is no comprehensive data on confirmatory testing and HIV PCR test request rejections at National Health Laboratory Service laboratories in South Africa.Objective: This study assessed the metrics of routine infant HIV PCR testing at the Tygerberg Hospital Virology Laboratory, Cape Town, Western Cape, South Africa, including the proportion of rejected test requests, turn-around time (TAT), and rate of confirmatory testing.Methods: We retrospectively reviewed laboratory-based data on all HIV PCR tests performed on children ≤ 24 months old (n = 43346) and data on rejected HIV PCR requests (n = 1479) at the Tygerberg virology laboratory over two years (2017­2019). Data from sample collection to release of results were analysed to assess the TAT and follow-up patterns.Results: The proportion of rejected HIV PCR requests was 3.3%; 83.9% of these were rejected for various pre-analytical reasons. Most of the test results (89.2%) met the required 96-h TAT. Of the reactive initial test results, 53.5% had a follow-up sample tested, of which 93.1% were positive. Of the initial indeterminate results, 74.7% were negative on follow-up testing.Conclusion: A high proportion of HIV PCR requests were rejected for pre-analytical reasons. The high number of initial reactive tests without evidence of follow-up suggests that a shorter TAT is required to allow confirmatory testing before children are discharged.

Hepatitis B virus infection confirmation and infection status identification in blood donors without serological markers / 中国输血杂志

【Objective】 To confirm Hepatitis B virus (HBV) infections and identify infection status by excluding false positive in blood donors reactive to nucleic acid testing (NAT) but without serological markers (Seroneg-NAT). 【Methods】 Seroneg-NAT yields were selected among blood donors in Dalian Blood Center from November 1, 2010 to February 28, 2021, and their HBV DNA was further confirmed with TaqMan HBV DNA quantification or virions concentration by polyethylene glycol (PEG) precipitation combined with in-house nested PCR targeting the S, BCP, PreS/S and Precore/core regions of the viral genome, and follow-up test was carried out, including blood routine screening and HBsAg, anti-HBs and anti-HBc testing. HBV infection was confirmed by HBV DNA yielding and anti-HBs/anti-HBc seroconversion in follow-up testing, and HBV DNA was further sequenced if necessary. 【Results】 During the period of 10 years and 4 months, 0.03% (126/466 911) Seroneg-NAT yields were selected, of which 46.8% (59/126) were HBV DNA+ and 53.2% (67/126) were unconfirmed. Among 126 Seroneg-NAT yields, 40.5% (51/126) were involved in follow-up test, of which 28 were HBV DNA+ and 23 were unconfirmed. HBV infections were confirmed in 48% (60/126) of Seroneg-NAT yields. Of follow-up donors, 54.9% (28/51) were identified as early infection before seroconversion, 2.0% (1/51) seronegative occult HBV infection (OBI), and 37.3% (19/51) NAT false positive. There were still 5.9% (3/51) classified as the indetermination. 【Conclusion】 Nearly half Seroneg-NAT yields in Dalian blood donors were infected with HBV and more than 50% were early infections before seroconversion. The majority of HBV DNA unconfirmed without serological markers were false positives.