ating to an 86% success rate for full, single source profiles.
Two toenail samples returned profiles with greater than 100%
completeness (cases 8 and 26). Both profiles contained additional
alleles compared with those of the conventional samples of each
case. The additional alleles observed were much lower in height
than the major profiles of the samples. In both toenail samples, the
major profile matched that of the conventional sample (data not
shown). The additional alleles are suspected to be as a result of a
contamination event. As the extraction and amplification blanks
were negative for these samples, the source of contamination is
likely to be from the nail sample itself. Re-extraction ofthe samples
using the same method resulted in similar levels of profile
contamination (data not shown). One of the samples was rewashed
using the washing steps from the optimised organic
extraction protocol, followed by extraction with the QIAGEN
method. The resulting profile did not show contamination and
contained a full profile matching that of the conventional sample
for that case (data not shown). This finding indicates the wash
procedure employed for the QIAGEN method may not always
remove all contaminating material from the toenail sample and
that a more rigorous sample wash (such as that used in the
optimised organic extraction) may be required. None of the minor