Teichmann Test
Definition
Confirmatory crystal test. Glacial acetic acid and sodium chloride convert haem to brown, rhombic haemin (ferriprotoporphyrin chloride) crystals. Older, less reliable on aged stains than Takayama.
- Type
- Confirmatory crystal test
- Reagents
- Glacial acetic acid, sodium chloride
- Product
- Brown, rhombic haemin (ferriprotoporphyrin chloride) crystals
- Reliability note
- Less reliable than Takayama on aged stains
Common questions
How does the Teichmann test compare to the Takayama test in current casework use?+
Both are confirmatory microcrystal tests for blood, but the Teichmann test's crystals form less reliably on old or degraded bloodstains, so where a choice exists, Takayama is generally preferred for aged evidentiary stains, with Teichmann more commonly used as a secondary or historical comparison test.
Does a positive Teichmann test identify the species the blood came from?+
No. The reaction confirms the presence of haemoglobin-derived haemin and works across species, so a positive result establishes blood is present but a separate species-specific test, such as an immunological or antibody-based method, is required to determine whether it is human.
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