RESUMEN
OBJECTIVES: To validate a Gelatin Particle Agglutination (GPA) test for HIV using dried blood spots with a view to applying the test in large epidemiological studies. DESIGN: A method comparison study with standard enzyme linked immunosorbent assay (ELISA) using the Recombigen HIV-1/2 kit as the gold standard. SETTING: Blair Research Laboratory, Harare, Zimbabwe. SUBJECTS: Sera and dried blood spots samples were available from 379 women from Mbare, Harare and Mupfure, Shamva District, Zimbabwe who had participated in HIV studies conducted by Blair Research Laboratory. MAIN OUTCOME MEASURES: Results of the GPA and Recombigen HIV-1/2 ELISA using serum and dried blood spots. RESULTS: With the Recombigen HIV-1/2 ELISA as the gold standard, sensitivity and specificity of the GPA were 100% and 99.2% respectively using serum. With dried blood spots sensitivity and specificity of the GPA test were 100%. The cost of analysing one sample, based on cost of reagents and accessory materials only, was Z$300 for GPA compared to Z$1,200 for ELISA. Furthermore, hands-on time was significantly reduced with the GPA compared to ELISA. CONCLUSION: The GPA method is simple, less labour intensive and much cheaper, yet is equally sensitive when compared to standard ELISA. The high sensitivity with blood spots makes the test ideal for large-scale epidemiological studies in remote rural areas with no infrastructure for advanced diagnostic methods.