Abstract
Abstract
Background
Accurate Human Immunodeficiency Virus (HIV) viral load (VL) testing is essential for monitoring antiretroviral therapy (ART) and detecting treatment failure. In resource-limited settings such as Njombe Region, Tanzania, laboratories often face prolonged turnaround times (TAT) and suboptimal sample transport and storage. While HIV Ribonucleic Acid (RNA) degradation during extended storage of VL samples is well documented, its impact on routine, high-volume VL testing remains unclear. This study quantified the association between laboratory processing delays and reported HIV VL results.
Methods
We conducted a cross-sectional secondary analysis of VL data from Njombe Town Council Hospital Laboratory (October 2024–March 2025,
N
= 18,271). After excluding 246 records with missing dates, 18,025 samples were analyzed. Three TAT intervals—collection-to-reception (clinic to lab), reception-to-registration (lab receipt to system entry), and registration-to-testing (system entry to assay performance)—were categorized into quartiles. Multivariable multinomial logistic regression with predictive margins estimated associations between specific interval TAT delays
across quartiles
and VL categories.
Results
Median TAT from sample collection to result release was 22 days (IQR 13–36), exceeding the recommended ≤ 14 days. Only the slowest registration-to-testing quartile (Q4, 21–76 days) compared to the fastest quartile (Q1, 0–1 days) showed consistently fewer detectable VL results. Adjusted probability of Target Not Detected (TND) increased from 71.2% (fastest quartile) to 85.8% (slowest quartile) (RR = 1.205; 95% CI 1.196–1.214;
p
Conclusion
Prolonged registration-to-testing delays were strongly associated with lower reported HIV VL results. Consistent with time-dependent RNA degradation, this negative association demonstrates a distinct pre-analytical bias that may compromise patient care and clinical program monitoring. Therefore, interventions targeting workflow and laboratory system optimization are warranted—a conclusion likely generalizable to similar centralized HIV VL laboratories across low- and middle-income countries.