Comparative effectiveness of dried plasma HIV-1 viral load testing in Brazil using ViveST for sample collection.
BACKGROUND
Utilization of dried plasma for HIV-1 viral load testing would significantly decrease sample shipping costs.


OBJECTIVE
To describe the precision and reproducibility of ViveST(®) (ST) as a transportation method for shipping specimens for HIV-1 viral load (VL) testing.


METHODS
Thirty clinical plasma samples were used to generate replicate samples with HIV VL values of 4 log(10), 3 log(10) and 2 log(10) copies/mL for reproducibility testing and an additional 299 samples with HIV VL <50 copies/mL (99); 1.7 log(10) to 3.99 log(10) (100); and 4 log(10) to 5.99 log(10)/mL (100) were used to compare ViveST to frozen plasma samples using the VERSANT(®) HIV-1 RNA 3.0 Assay. Results were compared using Student t-test, Pearson correlation and Bland-Altman analyses.


RESULTS
Mean intra-assay variance among frozen and dried plasma triplicates was 0.15 log(10) and 0.09 log(10) copies/mL respectively (n=10, P=NS). Compared to frozen plasma, there was a mean reduction of 0.3 log(10), 0.27 log(10), and 0.35 log(10) copies/mL at the 4 log(10), 3 log(10), and 2 log(10) copy/mL samples respectively (n=30, all comparisons, P<0.01). Overall correlation between 299 frozen and ViveST samples was r=0.97, where 12 of 99 undetectable frozen VL were positive with ST, and 12 of 200 frozen detectable VL were undetectable with ViveST (mean VL 2.1, 1.9 log(10) copies/mL respectively).


CONCLUSIONS
HIV-1 viral load results using ViveST were reproducible, correlated well with frozen plasma, though yielding minimally lower values. Our data suggest that dried plasma for HIV-1 VL testing using ViveST has promise for use in HIV clinical practice.
Zanoni
Michelle
M
Retrovirology Laboratory, Federal University of Sao Paulo, Brazil.
Cortes
Rodrigo
R
Diaz
Ricardo S
RS
Sucupira
M Cecilia
MC
Ferreira
Denise
D
Inocencio
Lilian A
LA
Vilhena
Cintia
C
Loveday
Clive
C
Lloyd
R M
RM
Holodniy
M
M
D001938:Brazil; D003890:Desiccation; D015658:HIV Infections / Q000175:diagnosis* / Q000821:virology*; D015497:HIV-1 / Q000302:isolation & purification*; D006801:Humans; D010949:Plasma / Q000821:virology*; D015203:Reproducibility of Results; D013048:Specimen Handling / Q000379:methods*; D019562:Viral Load / Q000379:methods*