Seminal Stains | Medical Science Optional Notes for UPSC PDF Download

Seminal Stain Analysis

Tests for Detection of semen

Chemical Tests

Presumptive:

• Florence test
• Barberio's test
• Brentamine fast blue test (Seminal acid phosphatase test - qualitative)

Confirmatory:

• Acid phosphate test (quantitative)
• Identification of semen-specific glycoproteins (P30) of prostatic origin
• Microscopic examination, which includes assessing sperm motility after staining with dyes like hematoxylin and eosin or the 'Christmas tree' stain.

The detection of spermatozoa under light microscopy is regarded as the benchmark or gold standard.

Presumptive Chemical Tests

Florence Test: The stain is removed, dried on a glass slide, and covered with a coverslip. A drop of Florence solution (8% w/v iodine in water with 5% w/v potassium iodide) is introduced under the coverslip. If semen is present, dark brown rhombic crystals, resembling hemin but larger, will promptly emerge, arranged in clusters or rosettes of choline periodide.

Barberio's Test: When a saturated aqueous or alcoholic solution of picric acid is applied to a dried stain extract on a glass slide covered with a coverslip, it generates yellow, needle-shaped crystals of spermine picrate.

The acid phosphatase test is employed for seminal stain identification.

• Prostatic acid includes acid phosphatase.
• Acid phosphatase concentrations persist in semen recovered from the vagina for up to 36 hours after deposition.
• Results are quantified in Bodansky units.
• The acid phosphatase test is conclusive, particularly in cases where there are no demonstrable sperms or in instances of Aspermia.
• Definitive confirmation of semen involves discovering at least one intact spermatozoon or utilizing electrophoretic LDH isoenzyme detection for sperm identification.

Chemical Tests

• Ammonium molybdate test
• Choline and spermine test
• Creatine Phosphokinase

Serological Tests

• Precipitin test
• Grouping of seminal fluid (identifying specific agglutinable substances)
• Gel diffusion precipitate reaction
• Immunodiffusion
• Isoelectric focusing
• Identification of at least one intact spermatozoon
• Electrophoretic LDH isoenzyme detection of sperm

Seminal stains-Repeats 

1. Enumerate various physical and chemical tests to confirm the presence of semen in given sample (2000). 
2. Enumerate the tests performed for examination of suspected seminal stains. Describe confirmatory tests for seminal stains (2003). 
3. Describe the procedures of medical examination and methods of preserve trace evidences to detect semen as a proof of sexual offence of a 18 year's old female (2004). 
4. What are various tests to detect semen? Describe the confirmatory tests for seminal stains. (2013)
5. Define rape and write about various tests to detect semen. (2016)