Question

Which of the following is used to evaluate disinfectant?

• A. $ \text{Widal test} $
• B. $ \text{VRDL test} $
• C. $ \text{Chick Martin test} $
• D. $ \text{None of these} $

Hint:

Remember: Chick Martin test evaluates disinfectants under real-use conditions; Widal test is for typhoid.

Answer 1

The Correct Option is C

The Chick Martin test is a classical method used to evaluate the efficacy of disinfectants in the presence of organic matter (e.g., yeast, proteins).

It improves upon the Rideal–Walker test by simulating more realistic conditions found in clinical and environmental settings.
This test involves the comparison of phenol coefficient of a disinfectant in the presence of organic load.

Widal test — Used for serological diagnosis of typhoid fever, not for disinfectants.

VRDL test — Refers to Viral Research and Diagnostic Laboratory tests for viral infections like HIV, hepatitis, etc.

Hence, both (A) and (B) are unrelated to disinfectant evaluation.

Answer 2

The question asks which test is used to check how well a disinfectant works. Let's look at each option:

1. Widal test: This is a serological agglutination test used to detect antibodies against Salmonella typhi and Salmonella paratyphi in a patient's blood, helping diagnose typhoid fever. It has nothing to do with testing chemical disinfectants.
2. VRDL test: The Venereal Disease Research Laboratory test is a flocculation test used to screen for syphilis by detecting antibodies against the bacterium Treponema pallidum. Like the Widal test, it is a diagnostic serology test, not a disinfectant evaluation method.
3. Chick Martin test: This is a standardized microbiological method used specifically to measure the germ killing power of a disinfectant in the presence of organic matter such as protein or yeast, which mimics real world conditions like wounds or feces. The result is expressed as a phenol coefficient, comparing the disinfectant's activity against standard phenol under identical conditions.
4. None of these: Since the Chick Martin test is a genuine, established method for disinfectant evaluation, this option cannot be correct.

Widal and VRDL both test for antibodies in human blood samples and belong to diagnostic microbiology, while the Chick Martin test belongs to a completely different area, disinfectant efficacy testing, which directly answers what the question is asking.

So the correct answer is Chick Martin test.