Evaluation of the ap, psa and rsid tests compared to the dna typing for semen detection in forensic medicine

arezu Abdi,1,* Azam soleimani,2 Zohreh baratieh,3 Alireza saburi,4 Fardin mardani,5

1. Legal Medicine Research Center, Legal Medicine Organization, Tehran,Iran.
2. Legal Medicine Research Center, Legal Medicine Organization, Tehran,Iran.
3. Legal Medicine Research Center, Legal Medicine Organization, Tehran,Iran.
4. Legal Medicine Research Center, Legal Medicine Organization, Tehran,Iran.
5. Legal Medicine Research Center, Legal Medicine Organization, Tehran,Iran.

Abstract

Introduction

Serological typing for detection and identification of semen is typically done by using ap, psa, and rsid tests in forensic medicine. therefore, accurate identification of body fluid may provide crucial information about the events of crime scene. studies have shown that current methods do not provide the level of specificity or sensitivity required by the forensic field. therefore, the results of these methods are often incompatible with dna typing results. the purpose of this study was to evaluate the charactristics of ap, psa, and rsid tests compared with dna typing results.

Methods

A total of 43 samples of evidence related to sexual assault were evaluated with ap, psa and rsid, respectively.then, dna extraction from spots was performed with the qiaamp dna investigator kit. pcr amplification was performed using the ampflstr yfiler kit for total samples. raw data obtained abi 3130 was analyzed using genemapper (applied biosystems) software.

Results

Data of dna typing showed that, 93.33% of ap and psa positive response are true positive and 76.92 % of ap and psa negative response are false negative. also for rsid was 100% and 84.84% respectively. percentage of accuracy, specificity, sensitivity, pvc and nvc for both psa and psa were 72.9, 23, 93.33, 78.94 and 23.07, respectively, and for rsid 32.6, 15.1, 100, 26.31 and 15.1, respectively.

Conclusion

Use of both ap and psa for screening semen can increase the chances of obtaining a dna profile. also, the rsid alone does not have accuracy required for semen identification. so, results of dna typing is the ultimate valid respons.

Keywords

Screening, rsid, dna typing, ap, psa