Test for the virus in the first week, for antibodies after it

**Chikungunya virus infection should be considered in patients with acute
onset of fever and polyarthralgia** — joint pain in multiple joints —
**especially travellers who recently returned from areas with known
transmission.**

Fever plus joint pain plus a recent trip is the trigger.

Which test depends on the timing

The virus is present in blood early and gone later; antibodies are absent
early and present later. A test chosen for the wrong week returns a negative
that means nothing.

Laboratory diagnosis is generally done on serum or plasma, to detect virus,
viral nucleic acid, or virus-specific IgM and neutralising antibodies.

The confirmation step

**A positive chikungunya virus-specific IgM antibody test result should be
confirmed by neutralizing antibody testing at a state public health
laboratory or CDC.**

IgM tests cross-react between related viruses — dengue and Zika circulate in
the same places and are carried by the same mosquitoes. A positive IgM is a
strong signal and not a diagnosis, and the neutralising antibody test is what
separates them.

Reporting

Chikungunya virus disease is a nationally notifiable condition. Providers
are encouraged to report suspected cases to their state or local health
department **to facilitate diagnosis and mitigate the risk of local
transmission**.

Both halves of that matter. The health department is the route to the
confirmatory testing above — and an imported case in a place where the
mosquito lives is how local transmission starts.

**Contact your state or local health department for assistance with
diagnostic testing**, and note that some tests are not currently available at
the CDC.

Source: Centers for Disease Control and Prevention.