What this test measures
A malaria antigen rapid diagnostic test (RDT) is a small lateral-flow card that detects two parasite proteins in a drop of blood: HRP-2 (histidine-rich protein 2, specific to Plasmodium falciparum) and pLDH (parasite lactate dehydrogenase, common to all Plasmodium species, with species-specific bands available). A positive band line appears within 15–30 minutes if the relevant parasite protein is present.
Most Indian labs run a combo card that distinguishes P. falciparum from non-falciparum (mostly P. vivax). It does not replace microscopy — it complements it by giving a fast preliminary answer, especially after hours or in outpatient and emergency department settings.
Why it matters
In high-malaria-burden Indian states (Odisha, Chhattisgarh, Jharkhand, the Northeast, parts of Maharashtra), rapid antigen tests have transformed front-line malaria management. They can be done in clinics without a microscopist, give an answer in 20 minutes, and identify P. falciparum — the species responsible for almost all severe malaria deaths — at the point of care.
Known limitations: the HRP-2 band can stay positive for weeks after successful treatment (so it cannot be used to monitor cure), some P. falciparum strains in eastern India and Africa have HRP-2 deletions and give false negatives, and very low parasitaemia (<100 parasites/µL) may not register. For all these reasons, a peripheral smear is usually done alongside the RDT.
How to prepare
No fasting or special preparation required. Like the MP smear, sampling during a fever spike maximises sensitivity. Inform the lab of any anti-malarial medication taken in the previous 4 weeks, as HRP-2 antigen can persist post-treatment.
Markers & reference ranges
Reference ranges below are typical adult values. Your lab's reported range may differ slightly based on the assay platform and patient demographics — always read your report against the range printed on it.
| Marker | Normal range | If low | If high |
|---|---|---|---|
| P. falciparum HRP-2 (—)[1] | Negative | — | Positive — indicates active or recent P. falciparum infection. Treat as falciparum malaria immediately. Note: HRP-2 can stay positive for 2–4 weeks after cure, so a positive result in a recently treated patient is not reliable. |
| Pan-malaria pLDH (—)[1] | Negative | — | Positive in pan band with negative HRP-2 = non-falciparum (most commonly P. vivax in India). Positive in both bands = P. falciparum (possibly with mixed infection). Treatment depends on species. |
Malaria antigen RDT vs peripheral smear
| Feature | Antigen RDT | Peripheral smear |
|---|---|---|
| Turnaround | 15–30 min | 1–2 h |
| Equipment | Card only, no microscope | Microscope + trained technologist |
| Species ID | Pf vs non-Pf (limited) | All 5 species |
| Quantifies parasites | No | Yes (% parasitaemia) |
| Use after treatment | Can stay positive 2–4 weeks | Clears within 2–7 days of effective Rx |
| Detection limit | ~100 parasites/µL | ~50 parasites/µL |
Frequently asked questions
Is the rapid antigen test as good as the smear?
For making a fast clinical decision, yes — especially for P. falciparum. But it does not measure how heavy the infection is, may miss low-density infections, and can stay positive after cure. Most Indian doctors order both.
My antigen test is positive but the smear is negative. What does that mean?
A few possibilities: very early infection (parasites too few to see on smear), recent treatment (parasites cleared but HRP-2 still circulating), or rarely a false positive. Your doctor will take the antigen result seriously and either treat or repeat the smear in 12–24 hours.
How long does HRP-2 stay positive after treatment?
Typically 2–4 weeks after successful treatment of P. falciparum malaria. This means the RDT cannot be used to confirm cure or to diagnose a relapse within that window — a smear or pLDH-based test is needed instead.
Are there malaria strains the RDT misses?
Some P. falciparum strains in eastern India, parts of Africa and South America have deletions of the HRP-2/HRP-3 genes and give false-negative RDT results. If your doctor suspects malaria despite a negative RDT, a smear or PCR is essential.
Should I use a home malaria self-test?
Self-tests sold online are not a substitute for laboratory diagnosis. Malaria can progress to severe disease within hours, so any fever after travel to an endemic region needs prompt medical evaluation and a lab-quality test.
Does the antigen test work for P. vivax (the common species in Mumbai)?
Yes — combo RDTs detect pLDH from all Plasmodium species, and the non-falciparum band picks up P. vivax. Sensitivity for vivax is slightly lower than for falciparum, so a smear is run in parallel when vivax is suspected.
How fast will I get the report?
The card reaction itself takes 15–30 minutes. With sample collection and reporting, most Mumbai and Thane labs deliver a digital report within 1–2 hours.
Related Infectious Disease tests
Tests commonly ordered alongside MALARIAL ANTIGEN, or that help interpret an unexpected result.
Sources & references
- WHO — Malaria Rapid Diagnostic Test Performance · accessed 2026-05-30T00:00:00.000Z
- CDC — Malaria Diagnosis (Rapid Diagnostic Tests) · accessed 2026-05-30T00:00:00.000Z
- NVBDCP India — Diagnosis and Treatment of Malaria · accessed 2026-05-30T00:00:00.000Z
- NCBI StatPearls — Malaria · accessed 2026-05-30T00:00:00.000Z
Book with Zelnoo
Get your MALARIAL ANTIGEN test done at home — transparent prices, NABL-accredited labs.
Zelnoo lets you compare diagnostic test prices across NABL-accredited labs in Mumbai & Thane, book a free home phlebotomist visit, and receive digital reports in 24–48 hours into a consent-first report vault. No subscriptions, no membership fees — pay only for the test you book.
Book MALARIAL ANTIGEN now