A positive ELISA means the test detected antibodies or antigen, suggesting current or prior infection, but it is not definitive. Clinicians order confirmatory tests (for example, Western blot or PCR) and interpret results with symptoms and exposure history. Because false positives occur, avoid assuming diagnosis until confirmation. If confirmed, you'll receive treatment, monitoring, counseling and advice to reduce transmission risk.

ELISA (enzyme-linked immunosorbent assay) is widely used to detect antibodies or antigens for several infections, most commonly HIV. An HIV ELISA screens for HIV antibodies/antigens and a reactive result prompts confirmatory testing (e.g., Western blot or nucleic acid tests). ELISA is also used for hepatitis B/C, dengue, and Lyme disease, but positive results usually need confirmatory tests.

There is no single universal "normal range" for ELISA; values depend on the specific assay and manufacturer. Many antibody ELISAs use optical density (OD) ratio cutoffs such as: <0.9 negative, 0.9–1.1 equivocal/borderline, and >1.1 positive. Laboratories report qualitative interpretations (negative/indeterminate/positive) based on validated kit reference ranges and clinical context.

Common diseases tested using ELISA include HIV infection (antibody/antigen detection), hepatitis B (HBsAg and anti-HBV antibodies), and hepatitis C (anti-HCV antibodies). ELISA is widely used for screening, diagnosis, and monitoring immune responses because it detects specific antibodies or antigens with high sensitivity and specificity, often as part of confirmatory testing alongside molecular methods.

An ELISA run in the laboratory typically takes a few hours, but real‑world turnaround depends on sample transport and batching: most results are reported the same day to within 1–3 days. If an initial result is reactive and requires confirmatory testing (for example, Western blot or PCR), final confirmation can take several additional days to a couple of weeks. Check with your clinic for exact timing.

ELISA test costs vary widely by country and purpose. In clinical labs, individual ELISA diagnostics typically cost about $10–$200 (roughly ₹300–₹1,500 in India). Research‑grade ELISA kits (96‑well) cost about $200–$600 per kit, making per‑sample reagent costs around $2–$10, plus technician and lab charges. Final price depends on test type, lab accreditation, and confirmatory testing.