AEGiS-13IAC: Dried blood spots (DBS) : a valuable tool for HIV surveillance in developing or tropical contries.

13th International AIDS Conference

Durban, South Africa - July 9-July 14, 2000

Dried blood spots (DBS) : a valuable tool for HIV surveillance in developing or tropical contries.

Int Conf AIDS 2000 Jul 9-14; 13:(abstract no. ThOrC668)

Solomon SS, MCGarvey S, Rodriguez I, Amalraj E, Ganesh AK, Mayer K
S.S. Solomon, 1, Raman Street Tnagar, Chennai 600 017, India, Tel.: +91 44 626 3106, Fax: +91 44 825 6900, E-mail: yrgcare@vsnl.com

BACKGROUND: We undertook a research to study the stability of Dried Blood Spots collected in the hot and humid field conditions of Southern India and compared their sensitivity and specificity to that of Serum ELISA and Western Blot.

METHODOLOGY: Study comprised of 12 blood spots each of 59 known HIV+ and 30 known HIV- samples of clients who attended the YRG medical centre, dried and left at ambient conditions. We refrigerated two cards of each sample every 24 hours. We eluted the dried blood spots and performed an ELISA test (Orgnanan) and Western Blots (BIORAD).

RESULTS: DBS elutes for ELISA identified correctly, on days 1 to 6 both the positive and negative samples. The mean é SD of the Optical Density (OD) of HIV+ samples for day 1-6 ranged from 1.031 é 0.058 to 1.024 é 0.55. The mean é SD of the OD of HIV- samples for day 1-6 ranged from 1.414 é 0.241 to 1.274 é 0.100. The serum samples by ELISA however gave three false positives. The DBS elutes for Western Blot were indeterminate in case of 5 positive samples on each of days 1-6, giving a sensitivity of 91.5%. The serum Western Blots had a sensitivity of 100%. The OD difference between day 1-6 in both positive and negative samples were statistically significant (P = 0.001) using repeated measures ANOVA.

CONCLUSION: National AIDS Control Organization, India, recommends use of a single ELISA for surveillance. These results demonstrate the reliability and stability of DBS stored in tropical humid environmental condition upto duration of 6 days. DBS emerges as a convenient, cost effective and powerful tool for sero-surveillance in areas that lack refrigeration or sample processing facilities. The indeterminate results by Western Blot in DBS elute for the known HIV +ve samples requires further study.

Keywords: AEGIS, HIV, HIV Infections, HIV Seropositivity, HIV Antibodies, Acquired Immunodeficiency Syndrome, Blotting, Western, Exanthema, Enzyme-Linked Immunosorbent Assay, HIV Seroprevalence, HIV Seronegativity, India, Sensitivity and Specificity, Blood Stains, Human, blood, epidemiology, immunology
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ThOrC668