Question

Which is the microbiological test for diagnosing Leptospira infection?

• A. Cold agglutination
• B. Standard agglutination
• C. Microscopic agglutination test (MAT)
• D. None of these

Hint:

The gold-standard serological test for leptospirosis uses agglutination viewed under the microscope.

Answer 1

The Correct Option is C

Step 1: Confirming leptospirosis in the laboratory uses either direct visualisation of the spirochaete or a serological assay.
Step 2: The benchmark serological method is the microscopic agglutination test, in which patient serum is reacted against live Leptospira serovars - it is regarded as the gold standard.
Step 3: Direct methods such as dark-field microscopy, immunofluorescence and stained light microscopy support diagnosis, but MAT remains the reference test.
Step 4: Cold agglutinins relate to Mycoplasma and standard agglutination to typhoid, so neither fits Leptospira; MAT is the answer.
\[\boxed{\text{Microscopic agglutination test (MAT)}}\]