Sample collection and storage
An inappropriate collection, storage and transport of samples can influence or even destroy a subsequent hormone analysis. Therefore, collecting and storing samples properly is extremely important for generation of reliable hormone data. The procedure and frequency of sample collection depends on the type of sample to be collected, the type of study, the species involved and the conditions under which the animals live (e.g. zoo or wild). Therefore, no detailed rules about which and how samples should be collected can be given here. This needs to be discussed individually between you and us.
Important aspects to consider when collecting and storing samples:
- A reliable assessment of endocrine state cannot be made by a single analysis. Thus, usually samples have to be collected over longer time periods (the frequency depending on the research question) to ensure reliable interpretation of the hormonal data. For example, a single elevated progestogen concentration in a blood, urine or faecal sample does not necessarily indicate pregnancy; it may as well indicate that the female is in the luteal phase of her ovarian cycle.
- Make sure that each sample is collected properly (and is of sufficient size and quality) and stored in an appropriate way. For example, cross-contamination of samples (e.g. urine with feces or vice versa) and inappropriate storage (i.e. faecal sample stored in alcohol for longer periods) may both render hormone results unreliable. Generally, collection of large sample volume/mass should be avoided (see Service: Options, costs, limitations).
- Freezing samples (at -10°C or below) is the most suitable and preferred method for storage of all types of samples. Where this is not possible (e.g. at remote field sites), alternative methods, such as simple extraction of faeces directly in the field and storing faecal extracts rather than neat faeces should be used. We have tested and established such methods and can provide the protocols for them after consultation.
- Sample containers should be appropriate for the type and amount of the sample collected (we can provide suitable containers upon request) and must be labeled properly (e.g. using resistant sticky labels and a pencil for labeling) in order to avoid loss of information on sample identity (usually happening during transport and freezing/thawing processes), rendering analysis meaningless. In this respect, preparation of a sample collection list (preferably an excel file) for crosschecking purposes and recording of relevant information and notes is highly recommended.
- For transport of biological samples (potentially harmful material) from non-EU countries to Germany an export and import permit are usually required. The specific permits you need and the specific regulations to be followed depend on factors such as type of sample, how samples were treated, the species from which samples have been collected, the country of origin etc. Since the procedures of applying for and issuing permits usually take several weeks, it is strongly recommended that you inform yourself well in advance of the transport and, in case samples should be send to us, contact us early enough for discussing the issue.
More information on aspects of sample collection, handling, storage, analysis and applications of non-invasive hormone measurements in studies under both captive and wild conditions can be found in the following papers:
Kalbitzer U; Heistermann M (2013). Long-term storage effects in steroid metabolite extracts from baboon (Papio sp.) faeces - a comparison of three commonly applied storage methods. Methods Ecol Evol 4: 493-500.
Hodges JK, Heistermann M (2011): Field endocrinology: guidelines, methods and applications for monitoring hormonal changes in free-ranging primates. In: Field and Laboratory Methods in Primatology: A Practical Guide. J. M. Setchell, D.J. Curtis, eds. Cambridge, Cambridge University Press, pp 353-370.
Hodges, J.K.; Brown, J.L. & Heistermann, M. (2010): Endocrine monitoring of reproduction and stress. In: Wild Mammals in Captivity: Principles and Techniques for Zoo Management. Kleiman, D.G., Thompson, K.V., Kirk Baer, C., eds. Chicago: The University of Chicago Press, pp 447-468.