Dipstick Test
Definition
A format in which reagents are embedded in pads on a solid strip. The strip is briefly dipped into or pressed against the sample; the colour change on the pad is read against a reference chart. Hemastix is the standard forensic example for blood.
- Format
- Reagent pads on a solid strip
- Reading method
- Colour change against a reference chart
- Forensic example
- Hemastix, for blood detection
- Result type
- Presumptive
Common questions
What can cause a false positive on a dipstick blood test?+
Peroxidase-like activity from plant material, certain metals, or some cleaning agents can trigger the same colour change as blood, which is why a positive dipstick result is treated as presumptive and followed by a confirmatory test before it is reported as blood.
Why choose a dipstick test over a spray-based presumptive test at a scene?+
A dipstick reads a small, targeted sample directly and gives a quick colour result without aerosolising reagent across a wider area, which suits testing a discrete stain rather than screening a large surface for latent bloodstaining.
Related terms
- Bluestar
- A proprietary reformulation of luminol (brand name: Bluestar Forensic) that uses a modified buffer and reagent concentration to produce chemiluminescent detection of...
- Buffer System
- The pH-controlling salt mixture in a spray reagent. The buffer in Bluestar is designed to maintain an alkaline pH for the luminol...
- Chromogenic Pad
- The reactive zone on a Hemastix strip impregnated with a reduced chromogen (tetramethylbenzidine in some formulations) and a peroxide source. Contact with...
- Haematuria
- The clinical term for blood in urine. Hemastix was developed as a urinalysis tool to detect haematuria and was later adopted by...
- Hemastix
- A commercial peroxidase test strip (Siemens/Bayer) containing a chromogenic pad that turns blue-green on contact with haemoglobin and hydrogen peroxide. Originally designed...