Which test is used to diagnose dengue fever?

Which test is used to diagnose dengue fever?

• A. Dengue serology
• B. Malaria smear
• C. CBC
• D. Blood culture

Answer: (A)

Dengue fever is diagnosed by laboratory tests that detect either the virus itself or the body's immune response to it. Dengue serology is the best answer among the options because it directly detects antibodies against the dengue virus (IgM indicates a recent infection and IgG can indicate past or secondary infection), providing confirmation of dengue. In the earliest days of illness, direct viral detection like NS1 antigen testing or RT-PCR can identify the virus, but among these choices serology is the most straightforward confirmatory test. The other tests are not specific for dengue: a malaria smear looks for malaria parasites, a CBC shows non-specific blood cell changes and is not diagnostic for dengue, and a blood culture searches for bacterial sepsis.

Dengue fever is diagnosed by laboratory tests that detect either the virus itself or the body's immune response to it. Dengue serology is the best answer among the options because it directly detects antibodies against the dengue virus (IgM indicates a recent infection and IgG can indicate past or secondary infection), providing confirmation of dengue. In the earliest days of illness, direct viral detection like NS1 antigen testing or RT-PCR can identify the virus, but among these choices serology is the most straightforward confirmatory test. The other tests are not specific for dengue: a malaria smear looks for malaria parasites, a CBC shows non-specific blood cell changes and is not diagnostic for dengue, and a blood culture searches for bacterial sepsis.