Describe
Report colour, shape and arrangement before interpretation.
MEDIVEERSETHE PRACTICAL HUBOBSERVE / REASON / EXPLAIN
Gram-stain recognition
Describe staining reaction, morphology and arrangement on a validated teaching image.
MICROSCOPY REFERENCE1 / 1 reference
1
Gram-positive coccus
The rounded purple-staining organism in this reference.
Zoom in, then drag to inspect. Keyboard: + / − to zoom, arrows to pan, 0 to reset. Tap the numbered markers to explore parts.
gram stain — reference view
Image: Mikael Häggström, M.D. Author info - Reusing images- Conflicts of interest: None Mikael Häggström, M.D. · Source / original · CC0Resized and converted to WebP; original colours retained.
Recognise and interpret
Differential staining reflects cell-envelope behaviour under the method; appearance does not determine species alone.
- Compare purple and pink organisms
- Describe cocci or bacilli
- Note arrangement and specimen quality
Limitations
Mixed flora, ageing cultures, technique and sample quality can complicate results.
Correlate
Use the sample site, culture and other validated tests.
At the viva table
Try answering aloud, then open the suggested answer. Examiner questions vary.
01 / Does Gram reaction identify the species?
No. It is one preliminary characteristic.
02 / Why can decolourisation affect interpretation?
It changes retention of the staining complexes.
03 / Can a clinical sample contain more than one morphology?
Yes. Mixed specimens need careful interpretation.
04 / Is an unstained clinical smear automatically safe?
No. Follow the laboratory’s risk assessment and biosafety protocol.