Comparison of dried blood spot (DBS) and plasma HIV-1 viral load measurements using Roche COBAS AmpliPrep/COBAS TaqMan assay, Northwest Ethiopia.

Abstract

Introduction: Quantitative determination of HIV-1 viral load measurements using plasma samples has been widely applicable for prompt monitoring at baseline and following initiation of highly active antiretroviral therapy (HAART). However, improper mixing of whole blood with anticoagulants during plasma sample processing, as well as limited access to specialized health facilities might hinder HIV diagnosis services. Considering its higher stability and increased accessibility in areas with poor laboratory settings, the dried blood spot (DBS) sample might be a suitable alternative approach for periodic monitoring of HIV-1 viral load measurements. Thus, in this study, we aimed to compare the quantitative determination of HIV-1 RNA levels using plasma and DBS samples among people living with HIV in Northwest Ethiopia.

Methods: An institutional-based analytical cross-sectional study was conducted from March to July 2020 using 48 paired plasma and DBS samples among people living with HIV at the HIV Treatment Center, Northwest Ethiopia. A total of four milliliters of venous blood was collected to harvest plasma and for DBS sample preparation. The HIV-1 RNA extraction, amplification, and quantification were performed using the Roche COBAS AmpliPrep/COBAS TaqMan version 2.0 assay. Data were managed and analyzed using SPSS version 26 software. Mean HIV-1 viral load measurements as well as the associations between plasma and DBS sample measurements were computed using a paired sample t-test and Pearson's correlation statistical tests, respectively. In addition, the level of agreement and the presence of proportional bias between sample measurements were performed using the Bland-Altman plot and linear regression models, respectively. A p-value of ≤ 0.05 with a 95% confidence interval was considered statistically significant.

Results: Among 48 people living with HIV, more than half (64.6%) of them were females. The minimum and maximum age of the study participants was 12 and 58 years, respectively. The mean difference with standard deviation (SD) of sample measurements (DBS minus plasma) HIV-1 viral load was 0.66 ± 0.70 log copies/mL. In the current study, a strong association with a significant linear correlation (r = 0.796) (p < 0.001) was obtained from Pearson's correlation analysis among HIV-1 viral load measurements between DBS and plasma samples. Moreover, the Bland-Altman plot also depicted a high level of agreement between the sample measurements.

Conclusions: The findings of the current study suggested that DBS samples could be considered as an alternative approach for periodic monitoring of HIV-1 viral loads to scale-up the HIV diagnosis and treatment coverage, particularly in areas with limited laboratory settings due to minimal invasive blood collection, higher stability at room temperature or ease of transportation, and decentralized sample collection approaches.