Hair Collection: Samples and Segments

Samples & Segments

Samples are sent to us as the un-trimmed lock of hair,  there is no need to trim before sending.We offer the option to analyse one or more separate hair segments. Segment sizes of 1 cm or 3 cm are the most popular choices, representing an average 1 month or 3 months of growth, respectively. There is no difference in price for assaying different lengths of segment.

If you wish to analyse segments separately, each segment would be analysed and charged as an individual sample. ARU Biomarker Laboratory quote for a full service – the labour cost involved in cutting your sample to size, or into segments as you request will be included in your quote.

Sample Analysis

When testing saliva samples, you have the choice to analyse your samples either “in singlet” or “in duplicate”. In duplicate analysis, one sample is assayed twice, and the results are used to produce a coefficient of variability (%CV) value that acts as a quality control check for the assay. For more information on coefficients of variability see Salimetrics.

Whilst ELISA is generally a reliable assay, it is possible to get variable results between assay duplicates for a number of reasons, and %CV values are usually required for publication. ARU Biomarker Laboratory will usually quote for 100% of your assays to be performed in duplicate as standard.

Hair cortisol analysis creates an additional area of potential variability due to fact that hormones must first be extracted from the hair before they can be assayed. Our lab’s extraction method has been optimised to produce low variation between extractions from the same sample of hair. However, information on this variability may be needed for publication. To obtain this measurement of extraction variability, a subsample of hair is extracted in duplicate. Duplicate extractions are labour intensive to perform and are therefore expensive, so as a cost-saving measure, we quote for extraction of 10% of your samples in duplicate, and the remaining 90% of extractions to be performed in singlet.

As standard we quote for single or 10% duplicate initial hormone extraction from the hair sample, with 100% duplicate ELISA analysis. Although, we can perform any percentage or number of duplicate extractions or assays in duplicate as you require though, so if you want a different number or to discuss duplicates please contact the technical team.  Below is a graphical representation of our standard extraction and analysis method and the results provided:


Your results will be emailed to you within 40 working days (~8 weeks) of arrival at our laboratory. The data will be emailed to you in a convenient Microsoft Excel format that includes mean cortisol concentrations and inter and intra assay coefficients of variability. We can provide additional data if required, and if so please let us know at the time of quoting.