Se me ocurrió de "raspar" = "scrape" y después encontré esto:

Definiciones de scraping en la web en inglés:

(usually plural) a fragment scraped off of something and collected; "they collected blood scrapings for analysis"


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Note added at 8 mins (2008-01-21 14:36:21 GMT)
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This is the link:

http://wordnet.princeton.edu/perl/webwn?s=scraping

In keeping with the "easy-to-understand" language of the rest of the document...

Skin Scrapings

Skin scraping examinations are used to identify fungal infections of the skin, mouth and nails. Fungus lives in the stratum corneum layer of the skin. KOH is used to digest this layer of skin so that the fungal growth with its visible hyphae and spores is exposed. Skin scraping examinations are indicated in areas of broken hair or baldness, presence of scaly lesions on the skin, crumbling or scaly nails or nail beds, and white plaque in the mouth.

a possibility

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Note added at 1 hr (2008-01-21 15:41:37 GMT)
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I cannot say for certain whether 'swab' is the correct term in this case, but it is used in this context:
Diabetic foot infection: dispelling the myths from Diabetic Foot, ... Myth 5: Diabetic foot infections do not always need investigation with wound swabs and ...
findarticles.com/p/articles/ mi_m0MDQ/is_1_8/ai_n13496111

Odor can also be a sign of foot infection. Infections do not usually occur without a ... Culture swabs are a way of identifying the germs in an infection. ...
www.bcfootandankle.com/footnfct.htm