RSID-Semen
Definition
Rapid Stain Identification of Semen: an immunochromatographic lateral-flow strip from Independent Forensics that detects semenogelin I and II with sensitivity to approximately 1 in 10,000-100,000 dilution of semen. Remains positive on aged and degraded samples independently of PSA results.
- Full name
- Rapid Stain Identification of Semen
- Manufacturer
- Independent Forensics
- Targets
- Semenogelin I and II
- Sensitivity
- Roughly 1 in 10,000 to 100,000 dilution
- Format
- Immunochromatographic lateral-flow strip
Common questions
Why is RSID-Semen used alongside a PSA test rather than instead of it?+
PSA (p30) is a widely used marker but can occasionally give a false positive from certain non-seminal sources and can decline with sample degradation. RSID-Semen targets a different protein, semenogelin, and remains positive on aged or degraded samples independent of the PSA outcome, so running both increases confidence in body-fluid identification.
Does a negative RSID-Semen result rule out semen on a sample?+
Not definitively. Very low sperm counts, vasectomised donors, or heavily degraded stains can fall below the assay's detection threshold, so a negative result is interpreted alongside other presumptive and confirmatory findings rather than treated as conclusive absence.
What makes semenogelin a good confirmatory target for semen?+
Semenogelin I and II are seminal vesicle proteins present at high concentration in seminal fluid and are more stable over time than sperm cell morphology, which is why the strip continues to detect semen in samples too degraded for microscopic sperm identification.
Related terms
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- Semenogelin I and II
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