Field study to determine the reliability of HIV viral load results shows minimal impact of delayed testing in South Africa.

Background: Understanding factors that impact HIV viral load (VL) accuracy in resource-limited settings is key to quality improvement. Objective: We evaluated whether testing delay and specimen storage between 25 °C and 30 °C before testing affected results. Methods: Between November 2019 and June 2023, 249 individuals on antiretroviral therapy, or with newly diagnosed HIV, were recruited from clinics in Cape Town and Gqeberha, South Africa, and three plasma preparation tubes were collected. One tube was tested within 24 h, while the others were stored uncentrifuged at ambient temperatures before testing. Centrifugation and testing of matched samples were performed on Day 4 and Day 7 after collection. Results: Time delay and ambient storage had minimal impact in specimens with a Day 1 VL of > 100 copies/mL. When grouped by Day 1 VL range, 96% - 100% of specimens at Day 4 and 93% - 100% at Day 7 had VLs within 0.5 log copies/mL of the first result. The greatest variability at Days 4 and 7 was observed when the Day 1 VL was < 100 copies/mL. However, there was no trend of increasing difference over time. Of Day 1 specimens with undetectable VL, or VL < 50 copies/mL, 80% had concordant results at Day 4 and 78% at Day 7. Conclusion: These results show that VL is stable in plasma preparation tubes for 7 days when stored at room temperature. There is significant variability in specimens with low VL, but variability is not affected by testing delay. What this study adds: Ideal HIV VL testing conditions are frequently unachievable in resource-limited settings. Data are needed on whether this impacts on the validity of test results. Our results provide reassurance that storage at ambient temperature for up to 7 days before testing does not substantially affect the VL result.

Comparison of automatic and manual methods for preparation of leukocyte-reduced red blood cell and plasma / 医疗卫生装备

Objective To compare the leukocyte-reduced red blood cells and plasmas respectively prepared by automated blood components separator and manual method so as to provide theoretical basis for automatic and standardized flow of blood components preparation.MethodsThe prepared red blood cells and plasma were measured on the hemoglobin concentration,mean corpuscular volume (MCV),red blood cell count (RBC),haematocrit (HCT),mean corpuscular hemoglobin (MCH),mean corpuscular hemoglobin concentration (MCHC),average red blood cell volume distribution width,plasma weight and protein content after the first separation,preparation time and etc.These results obtained from different methods were compared and analyzed.Results The plasma weight after the first separation which was one-off prepared were (267.57 ±16.31) g (by automatic method) and (246.06±22.48) g (by manual method) (P＜0.05) respectively.The preparation time were (66.66±9.01) s (by automatic method) and (162.33±22.00) s (by manual method) (P＜0.05) respectively.Other results had no significant difference (P＞0.05).Conclusion All blood components products in this research meet the criterion of GB 18469-2012.However,the quality and separation efficiency of products made by automatic blood component separator are obviously higher than those by manual method.

Clinical implications of elevated HIV-1 viral load results obtained from samples stored frozen in vacutainer plasma preparation tubes.

Studies have demonstrated that plasma samples collected and stored frozen using vacutainer plasma preparation tubes (PPT) may result in falsely elevated viral load (VL) values with the Roche COBAS TaqMan HIV-1 v1.0 test. At the University of Connecticut Health Center, a total of 349 samples from HIV-1-infected patients on HAART were collected and stored frozen in PPT. Viral load (VL) results were obtained using the Roche COBAS TaqMan HIV-1 v2.0 test (CTM v2.0) and Abbott RealTime HIV-1 assay (RealTime HIV-1). Of the 349 samples, 260 (74.5%) had VL values that differed by >0.5log10copies/mL; 64 of these were quantified by both assays. The remaining 196 samples were detected by CTM v2.0 but not detected in RealTime HIV-1: 62 of the most discordant samples in this category (CTM v2.0 detected/RealTime HIV-1 not detected) were further analyzed using two nested RT-PCR assays targeting pol integrase: full-length (864nt) and a highly conserved subregion (134nt). No HIV-1 RNA was detected in the discordant samples, confirming RealTime HIV-1 results. The increase in VL reactivity with the CTM v2.0 assay was presumably due to proviral DNA captured by the CTM total nucleic acid extraction chemistry but not the RNA-specific extraction procedure used in RealTime HIV-1. These results suggest that using CTM v2.0 with samples frozen in PPT could have significant clinical implications for HIV-1 patient management.