Brentamine fast violet B test
Definition
A two-component spot test in which sodium alpha-naphthyl phosphate (substrate) is hydrolysed by AP to alpha-naphthol, which couples with fast violet B diazonium salt to produce a purple-violet azo dye. A strong colour change within 30 seconds is presumptive positive for semen.
Related terms
- Acid phosphatase (AP)
- A group of phosphomonoesterase enzymes that catalyse the hydrolysis of phosphate esters at acid pH (optimum around pH 5). Multiple isoenzymes exist;...
- False positive
- A test result indicating diatoms consistent with ante-mortem aspiration in an organ sample when the diatoms actually arrived by contamination, post-mortem diffusion,...
- Fluorescent AP assay
- A more sensitive format using 4-methylumbelliferyl phosphate (4-MUP) as substrate. AP cleaves 4-MUP to 4-methylumbelliferone, which fluoresces under UV. Useful on aged...
- Prostatic acid phosphatase (PAP)
- The AP isoform secreted by acinar epithelial cells of the prostate gland, found in seminal plasma at concentrations of 25-1,000 U/mL, orders...
- Quantitative AP threshold
- A numerical activity level, expressed in units per litre of extract, above which a result is treated as semen-positive. Common thresholds range...
Explained in
- Acid Phosphatase Screening for SemenA two-component spot test in which sodium alpha-naphthyl phosphate (substrate) is hydrolysed by AP to alpha-naphthol, which couples with fast violet B diazoniu...