What samples are used in Zika testing?

What samples are used in Zika testing?

• A. Saliva/Urine: days 3-5, Serum: days 1-3
• B. Serum: days 1-3
• C. Saliva only
• D. Urine only

Answer: (A)

Testing Zika relies on detecting viral RNA in different fluids at different times after onset because the virus appears in each fluid on a distinct schedule. Early after infection, the virus is most reliably found in the blood, so testing serum in the first couple of days is most sensitive for RT-PCR. As the illness progresses, viral RNA can be detected longer in other fluids such as saliva and urine, so collecting saliva or urine a bit later increases the chance of detection. Therefore, testing serum during days 1–3 captures the initial viremia, while testing saliva or urine around days 3–5 broadens the window to catch ongoing viral shedding. This combined approach maximizes diagnostic yield across the typical infection timeline. Antibody (serology) testing, which isn’t the focus of this timing pattern, is usually done on serum as well, but detects the immune response rather than the virus itself. That’s why the best answer pairs serum testing early with saliva or urine testing a little later.

Testing Zika relies on detecting viral RNA in different fluids at different times after onset because the virus appears in each fluid on a distinct schedule. Early after infection, the virus is most reliably found in the blood, so testing serum in the first couple of days is most sensitive for RT-PCR. As the illness progresses, viral RNA can be detected longer in other fluids such as saliva and urine, so collecting saliva or urine a bit later increases the chance of detection.

Therefore, testing serum during days 1–3 captures the initial viremia, while testing saliva or urine around days 3–5 broadens the window to catch ongoing viral shedding. This combined approach maximizes diagnostic yield across the typical infection timeline. Antibody (serology) testing, which isn’t the focus of this timing pattern, is usually done on serum as well, but detects the immune response rather than the virus itself.

That’s why the best answer pairs serum testing early with saliva or urine testing a little later.