EXAMINATION FOR THE PRESENCE OF SEMEN IN MEDICOLEGAL CASES

Published in Forensic Pathology
Sunday, 13 August 2017 17:08
This includes examination of material obtained from vagina, stains from clothing, skin, hair, or other body parts for semen. This is carried out in cases of alleged rape or sexual assault.
 
Collection of Sample
 
  • Vagina: Direct aspiration or saline lavage
  • Clothing: When scanned with ultraviolet light, semen produces green white fluorescence. A small piece (1 m2) of clothing from stained portion is soaked in 1-2 ml of physiologic saline for 1 hour. A similar piece of clothing distant from the stain is also soaked in saline as a control.

LABORATORY PROCEDURES
 
1. MICROSCOPIC EXAMINATION FOR SPERMS
 
Presence of motile sperms in vaginal fluid indicates interval of < 8 hours. Smears prepared from collected samples are stained and examined for the presence of sperms.
 
2. ACID PHOSPHATASE
 
Acid phosphatase is determined on vaginal or clothing samples. Due to the high level of acid phosphatase in semen, its presence indicates recent sexual intercourse. Level of ≥50 U/sample is considered as positive evidence of semen.
 
3. DETERMINATION OF BLOOD GROUP SUBSTANCES
 
When semen is positively identified in vaginal fluid or other sample, test can be carried out for the presence of blood group substances in the same sample. The ‘secretor’ individuals (80% individuals are secretors) will secrete the blood group substances in body fluids, including semen.
 
4. FLORENCE TEST
 
This test detects the presence of choline found in high concentration in semen. To several drops of sample, add equal volume of reagent (iodine 2.54 g, potassium iodide 1.65 g, distilled water 30 ml); in positive test rhombic or needle-like crystals of periodide of choline form. False-positive tests can occur due to high choline content of some other body fluids.

Color Atlas of Forensic Medicine and Pathology

Published in Downloads
Saturday, 07 May 2016 00:27
Description: New York City has the largest medical examiner’s office in the United States, and the Brooklyn division is the busiest of the five boroughs. Charles A. Catanese received his Forensic Pathology fellowship training in New York, and then worked full time as a Medical Examiner in the Brooklyn office for more than 10 years. He has personally performed more than 4000 autopsies, including over 400 homicides.

Dr. Catanese has worked through several disasters, including TWA Flight 800, AA Flight 587, and more than nine months on the World Trade Center fatalities. He is currently the Chief Medical Examiner of Orange County, New York. Drawing on his wealth of knowledge and experience in solving some of the most difficult cases a forensic examiner could encounter, he assembles hundreds of images from his own work experience to present the Color Atlas of Forensic Medicine and Pathology.

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