In the laboratory analysis of a stain suspected to contain semen, which finding is regarded as CONFIRMATORY proof of the presence of semen?
- A Positive acid phosphatase reaction
- B Positive Florence test for choline crystals
- C Demonstration of spermatozoa or prostate-specific antigen (PSA, p30) ✓
- D Fluorescence of the stain under ultraviolet light
Correct answer: C. Demonstration of spermatozoa or prostate-specific antigen (PSA, p30)
Explanation
Identification of intact spermatozoa microscopically, or detection of PSA (p30) and semenogelin in azoospermic cases, confirms semen conclusively. Acid phosphatase elevation, the Florence test, Barberio test, and UV fluorescence are only presumptive screening tests because acid phosphatase is present in other tissues and Florence crystals can appear with other body fluids. Vasectomised or oligozoospermic assailants produce semen without spermatozoa, which is precisely why PSA serves as the confirmatory marker in those cases.
Reference: Parikh's Textbook of Medical Jurisprudence, Forensic Medicine and Toxicology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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