Table 1. Summary of samples used in the study, including plasma and dried blood spots (DBS).
| Origin | No. of samples | Type of sample | Collection year | ART status | Median VL log10 (range) | Storage condition | VL measurement | |
| Samples For validation (N = 151) | ||||||||
| Cameroon | 38 | Plasma | 2007 | Experienced | 4.05 (2.60–5.57) | −70°C | Roche Amplicor v1.5 | |
| Thailand | 31 | Plasma | 2006 | Naïve | 4.65 (3.14–5.58) | −70°C | Roche COBAS TaqMan | |
| Zambia | 27 | Plasma | 2006–2007 | Experienced | 4.26 (3.34–5.88) | −70°C | Roche Amplicor v1.5 | |
| 30a | DBS | 2005–2006 | Not applicable | Not applicable | −70°C | Not applicable | ||
| PT panels | 15 | Plasma | 2009–2010 | NAd | 4.13 (3.93–4.75) | −70°C | NA | |
| 10 | DBS | 2010 | NA | 3.78 (3.23–4.29) | −70°C or 5 DBS shipped at ambient | NA | ||
| Samples for application (N = 230) | ||||||||
| Vietnam | 72 | Plasma | 2007–2008 | Naïve | Not done | −70°C | Not done | |
| 72b | DBS | 2007–2008 | Naïve | Not done | −70°C | Not done | ||
| Malawi | 34 | Plasma | 2009 | Experienced | 4.07 (2.25–5.89) | −70°C | Abbott m2000rt | |
| Nigeria | 26 | Plasma | 2009 | Experienced | 4.02 (2.18–6.41) | −70°C | BioMerieux EasyQ | |
| 26c | DBS | 2009 | Experienced | 3.97 (2.18–5.64) | Room temperature for an average 85 days | BioMerieux EasyQ | ||
a
HIV negative specimens collected from pregnant women in Tanzania used for assay specificity analysis; b Plasma-matched DBS samples collected from voluntary counseling and testing (VCT) sites in Ho Chi Minh City enrolled in an HIV-1 threshold survey; cPlasma-matched DBS samples collected from patients enrolled in the Nigeria HIVDR perspective monitoring survey at 12-15 months after commencement of first line antiretroviral therapy; d Not available.