Hantavirus Test and Diagnosis: ELISA, PCR, and Serology

Hantavirus diagnosis is straightforward when the clinician thinks of it. Without exposure history, the disease is easy to miss in its early phase. This article explains the three main test types and when each is used.

Quick answer

Most hantavirus cases are confirmed by an ELISA detecting IgM and IgG antibodies. RT-PCR detects viral RNA and is most useful in the first week of illness. Plaque reduction neutralization tests are reference-grade and used for strain confirmation. Ask for hantavirus testing explicitly if you have had rodent exposure and develop relevant symptoms.

When to test

A clinician will consider hantavirus when these features align:

• Fever, muscle pain, and either acute respiratory distress (HPS suspicion) or acute kidney injury with thrombocytopenia (HFRS suspicion)
• Recent rodent exposure or residence in an endemic region
• No alternative explanation after standard workup

ELISA: the workhorse

Enzyme-linked immunosorbent assays detect IgM and IgG antibodies against hantavirus nucleoprotein. IgM is detectable from symptom onset and peaks at 1 to 2 weeks. IgG appears within 2 to 3 weeks and persists for years.

A positive IgM result with compatible clinical features is diagnostic in most settings. Some commercial assays are strain-specific. Reference labs run pan-hantavirus assays followed by strain typing if needed.

RT-PCR: viral RNA detection

Reverse transcription PCR detects hantavirus RNA in blood and, in some protocols, in urine. PCR is most useful in the first 7 to 10 days of illness, when viremia is highest. It is the test of choice in fatal HPS cases for postmortem confirmation.

PCR is not available in every hospital. In Europe, regional reference centers run the test. In the United States, state public health labs and the CDC handle confirmation. Turnaround time depends on transport.

Neutralization assays: the reference

Plaque reduction neutralization tests (PRNT) and focus reduction neutralization tests (FRNT) measure functional antibodies. They distinguish closely related hantavirus strains and are used in research and outbreak investigation. PRNT is not a routine clinical test.

Imaging and supportive labs

For HPS, chest imaging shows bilateral interstitial infiltrates and pleural effusions. Hematology shows hemoconcentration, thrombocytopenia, and the appearance of immunoblasts in the peripheral smear. These features in the right context support the clinical picture.

For HFRS, urinalysis shows proteinuria and hematuria. Serum creatinine rises in the oliguric phase. Platelet counts are typically low.

What to do if you suspect hantavirus

Tell your doctor explicitly: when you may have been exposed, what activity caused the suspected exposure, and which region. The exposure history is what triggers the right test order. Hantavirus testing is a separate request and is not part of routine fever workup outside endemic regions.