- Current experimental results show that fecal water is approximately 30-75% of the mass
of the fecal sample. Since we use mass as the basis for reporting hormone results, for example
as ng/g (nanograms of hormone per gram of feces), there is a great possibility of
error or uncertainty in the results if the fecal samples are not of the same
water content or consistency. The preferred method for ensuring all samples are of the same
consistency is lyophylization. Generally our lab prefers if fecal samples arrive
dry and free from external particle matter like seeds, stones, grass,
hay, and hair. It is more expensive and time consuming for our lab to dry (lyophylization)
fecal samples or do other sample preparation work.
- Consider the degree of water homogeneity acceptable for your analyis--from
watery to dry. It may be that the feces samples are uniform as to their moisture content so
analysis can begin without the drying step. If feces samples are not homogeneous, which is the
typical case, then drying is an option. Note that some steroids are water soluble and so
absorbing the water with a paper towel and throwing the paper towel away may also discard
your steroid. Dry feces can be obtained by lyophylization or air drying.
- Collect a fecal sample, we recommend gloves at all times.
- We only sample about 0.2 grams of feces so about 1 gram
is plenty for the lab --- 1 tablespoon of feces is all the lab needs but
you may want to collect and store more for your own needs or subsequent analyses.
- Collect a fecal sample as fresh and pure as possible, no hair or grass. Extract in
ethanol or freeze feces after collection and labelling. We prefer you label the samples
in sequential numerals (1,2,3...n).
- Ship fecal samples in dry ice or other cold medium.