HIV infection in Xi’an, China: epidemic characterization, risk factors to false positives and potential utility of the sample-to-cutoff index to identify true positives using Architect HIV Ag/Ab combo

Abstract

BackgroundIn China, although tremendous efforts has been made, the HIV/AIDS is still not controlled.ObjectivesThe study was carried out to determine the epidemic of HIV infection in Xi’an, analyse false positives (FP) risk factors and potential utility of sample-to-cutoff index to identify true positives using Architect HIV Ag/Ab Combo.MethodsA retrospective review for HIV screening by Architect HIV Ag/Ab Combo was performed in a teaching hospital in Xi’an between 2015 and 2016. The prevalence of HIV, positive predictive value (PPV) at different cut-off indexices (COI) were calculated. The epidemic of infections and risk factors for FP results were investigated.ResultsIn the study, the HIV prevalence and FP rate of Architect HIV Ag/Ab Combo were 0.076 and 46.08%, respectively. The Han Chinese, males and people aged < 40 years accounted for the majority of infections (98.29, 76.07 and 73.5%, respectively). 85.47% of the infections were transmitted through sexual contact (35.04% of male homosexual and 50.43% of heterosexual). COI at 1–10, 10–30 and ≥ 30, the PPVs were 0, 50 and 100%, respectively. The independent risk factors for FP, i.e., pregnancy and malignancy had a statistically significant association with FP (p < 0.05), and age had a very strong statistically significant association with FP (p < 0.001).ConclusionsIn Xi’an, sexual contact was the most important transmission mode for HIV, and the infections were predominantly identified in Han Chinese, males, young and middle-aged people. For Architect HIV Ag/Ab Combo, it can achieve 100% of PPV with COI ≥30, and the age was strongly statistically associated with FP.

The evaluation of low cut‐off index values of Elecsys® HIV combi PT assay in predicting false‐positive results

“…Results also showed that most patients with false-positive results were elders and females, which was consistent with previous studies. 17,18 Recent studies revealed that many factors, such as cancers, rheumatoid factors, autoimmune diseases, and pregnancy, might lead to poor specificity in HIV screening by the 4th-generation assay and cause an indeterminate result for the WB test. [19][20][21][22][23][24] More elderly patients in the false-positive group are more likely to suffer from underlying diseases.…”

Shift in HIV/AIDS Epidemic and Factors Associated with False Positives for HIV Testing: A Retrospective Study from 2013 to 2018 in Xi’an, China

“…By the end of September 2018, there were 849,602 people living with HIV (PLWH) in mainland China [ 15 ]. The epidemic is severe in some midwest provinces (Sichuan, Chongqing, Guizhou, Hunan, Henan) and border communities (Xinjiang, Guangxi, Guandong), with annual new HIV/AIDS cases more than 5000 [ 16 - 18 ].…”

HIV false positive screening serology due to sample contamination reduced by a dedicated sample and platform in a high prevalence environment

“…Using a combination of independent sample testing and different platform testing, for confirmation, we found that 85% of LP&E results were FP and therefore, LP&E result prevalence can be used as an indicator of FP rate. In other settings, the PPV for this assay approached 100% when using a higher positive threshold than recommended by the manufacturer (S/CO over 30) in European and Asian populations [ 7 – 9 ]. Given the high proportion of FP results among LP&E (S/CO <30) in our setting, the use of a higher threshold for positivity helped to identify cases likely to be false positive in our context, whereas the high proportion that tested negative when testing an independent sample highlights the importance of confirming HIV serology on a separately collected sample.…”

“…FP results usually generate LP&E S/CO signals as seen by other centres [ 2 , 6 , 7 ]. Using a combination of independent sample testing and different platform testing, for confirmation, we found that 85% of LP&E results were FP and therefore, LP&E result prevalence can be used as an indicator of FP rate.…”