Christmas tree staining
Definition
A two-step differential stain using Nuclear Fast Red (Kernechtrot) to stain the sperm head red/pink and Picroindigocarmine to stain the midpiece and tail blue-green. The red-green contrast makes spermatozoa immediately recognisable at 400x.
Related terms
- Acrosome
- A cap-like organelle covering the anterior half of the sperm head. It contains hydrolytic enzymes used in oocyte penetration. Forensically it appears...
- Azoospermia
- The absence of spermatozoa in ejaculate, whether due to obstructive causes (post-vasectomy) or non-obstructive causes (spermatogenic failure). Affects roughly 1% of men...
- Ghost head (decapitated spermatozoon)
- An isolated sperm head separated from its tail, commonly found in aged or dried stains. The head retains its oval morphology and...
- Sperm reporting conventions
- Standardised ways to record microscopy results: some labs report a count per high-power field (HPF), others report as present/absent, and some use...
- Spermatozoon (pl. spermatozoa)
- The mature male gamete: an oval head (4-5 microns) containing condensed nuclear DNA and an acrosomal cap, a short midpiece containing mitochondria...
Explained in
- Spermatozoa Identification by MicroscopyA two-step differential stain using Nuclear Fast Red (Kernechtrot) to stain the sperm head red/pink and Picroindigocarmine to stain the midpiece and tail blue-...