VHOSPITAL.CLINIC · Diagnostic Test
The malaria RDT (rapid diagnostic test) delivers a positive or negative result in 15–20 minutes from a finger-prick blood sample — enabling immediate treatment decisions without laboratory infrastructure.
RDTs detect Plasmodium-specific antigens (HRP2 for P. falciparum; pLDH or aldolase for other species) using lateral flow technology. The WHO recommends RDT-confirmed diagnosis before treatment in all settings.
A finger-prick blood sample (5 μL) is applied to the test cassette with buffer. Results appear as lines within 15–20 minutes. Two lines = positive; one line (control only) = negative; no lines = invalid. The HRP2 line persists for up to 4 weeks after successful treatment.
A positive HRP2 line indicates P. falciparum (or mixed infection). A positive pLDH-only line indicates non-falciparum malaria. All positive RDTs should trigger immediate treatment. False positives occur with rheumatoid factor; false negatives occur with HRP2-deletion P. falciparum strains (emerging in sub-Saharan Africa).
Sensitivity: 95–99% for P. falciparum (HRP2-based); 74–90% for non-falciparum species (pLDH-based). Specificity: 95–99%. Sensitivity decreases below 100 parasites/μL. HRP2 antigen persists 3–4 weeks post-treatment, causing false positives in treated patients.
For P. falciparum, HRP2-based RDTs achieve 95–99% sensitivity and specificity. They perform less well for non-falciparum species (74–90% sensitivity) and at very low parasitaemia. A negative RDT with high clinical suspicion should be followed by blood smear.
Yes. The HRP2 antigen from P. falciparum persists in the blood for 3–4 weeks after successful treatment. Do not use RDT to confirm cure — use blood smear or PCR for treatment response monitoring.
HRP2-deletion P. falciparum strains (increasingly common in parts of Africa) do not express the HRP2 antigen detected by most RDTs. Low parasitaemia early in infection, improper storage of test strips (heat/humidity), and technical errors can also cause false negatives.
Malaria RDT (HRP2/pLDH) helps confirm Malaria, which can cause these symptoms:
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