• Impression smears can be taken from any moist or greasy skin surface to see any inflammatory, neoplastic or other cellular infiltrates, also to look for acantholytic keratinocytes, bacteria and yeasts.
• They can also be taken from cut surface of a surgical specimen or post mortem specimen.

Uses

• Staphylococcal Staphylococcus spp, impetigo/folliculitis and furunculosis.
• Corynebacterial infections Corynebacterium spp, eg Ulcerative lymphangitis Ulcerative lymphangitis.
• Actinomycetic infections eg dermatophilosis, Actinomycosis Actinomycosis, Actinobacillosis Actinobacillosis and nocardiosis.
• Necrobacillosis.
• Botriomycosis.
• Clostidial infections Clostridium spp.
• Mycobacterial infections Mycobacterium spp.
• Suspected neoplasia.

Advantages

• Samples are easily and quickly taken and will allow immediate differentiation of neoplastic and infective disease in many cases.

Disadvantages

• Surface bacteria may not be causative as cattle lesions may be heavily contaminated with fecal bacteria.
• Although most neoplastic lesions will exfoliate cells, some (eg sarcomata) will not, so results may be erroneously negative.

Technical problems

• Impression smears will only be possible if intact skin is moist or greasy. Eroded skin may be secondarily infected.

Alternative techniques

• Skin biopsy with bacteriological culture from biopsy specimen. Skin biopsy
• Bacterial culture swab from skin surface. Skin swab
• Histopathology.

Time required

Preparation

• Clip hair - 2 minutes.

Procedure

• 5 minutes to take samples.
• 30 minutes laboratory time to stain and examine slides.

Decision taking

Criteria for choosing test

• Eroded skin surface or eroded surface to skin mass.

Risk assessment