FaridabadBy Dr B.C. Gupta, MD · 2026-09-15
Ask the Pathologist - MCQ of the Week. A short question to test how well you know common laboratory tests, with a plain-English explanation from Dr B.C. Gupta, MD (Pathology).
Q. A patient comes on day two of fever with body ache. Which dengue test is most likely to give a positive result at this stage?
- A. Dengue NS1 Antigen
- B. Dengue Serology (IgM antibody)
- C. Widal test
- D. Peripheral blood smear for malaria
Answer: A. Dengue NS1 Antigen
The NS1 antigen appears in the blood very early in dengue, from the first day of fever and usually up to about day five. This makes it the test of choice when a patient comes early. Dengue serology looks for antibodies, which the body takes longer to produce, so it is more useful from around day five onwards and can be negative if done too early.
The Widal test is for typhoid and the blood smear is for malaria. Both are useful in fever, but neither detects dengue. Because fevers can look alike in the first few days, your doctor may order more than one test or ask you to repeat a test later.
If you have fever with body ache, call the centre to confirm which test suits your day of fever before you visit.
