Читать книгу Fundamentals of Analytical Toxicology - Robin Whelpton - Страница 72

 The ideal sample is collected from the vertex (the crown) of the head by cutting approximately 2 mm from the scalp

 Take a sample of hair about the thickness of a pencil (100–200 hairs)

 Pinch the hair tightly with the fingers and tie with cotton thread at the root end before cutting

 Cut the sample as close as possible to the scalp, making sure the scissors are level with the scalp

 Still holding the sample tightly, align the cut root ends of the sample and carefully place flat on a piece of aluminium foil with the cut root ends projecting about 15 mm beyond the end of the foil

 Mark the root end of the foil and fold the foil around the hair and pinch tightly to keep in place

 Fold the foil again in half lengthwise

 Place the sample in a tamper-proof envelope. Complete and sign the request form, making sure that the donor also signs if necessary. If there are special instructions that do not appear on the form, but are felt relevant, make a note on a separate sheet and enclose with the sample

Nail clippings may be used to monitor uptake of antifungal drugs such as itraconazole and terbinafine (Leyden, 1998). In post-mortem work, whole nails should be lifted from the fingers or toes. This provides an even longer potential window for detecting exposure than hair. However, relatively little is known about the mechanisms of uptake and retention or drugs and metabolites in nail. In addition, the slower growth rate of nail, especially toe nail, as compared to hair makes segmental analysis, and hence interpretation of quantitative results, virtually impossible (Krumbiegel et al., 2016; Solimini et al., 2017).

Figure 2.2 Schematic of head hair collection