Yes, no problem. Provided there is sufficient material (>200 µl), there is no need to collect several samples.

You make us happy when you send samples with a volume of 0.5 ml (or more). For single-hormone immunoassays, we like to receive at least 200 µl of sample. Add 50 µl for each additional hormone/biomarker. If less than 200 µl are available, please inform us upfront. For LC-MS/MS analyses, send us at least 200 µl of specimen if available. We can handle most assay requests with smaller sample volumes, but it is always good to have some spare material.

In singlet assays, your sample will be measured only once, with duplicate assays you will receive the results of two separate measurements of the same sample. For your publication(s) you would compute the mean of both values and use this value for statistical tests. Do you need duplicates? Some reviewers question the validity of singlet immunoassay. Which is fine, but not always warranted. The best immunoassays are very reliable (intraassay coefficient of variation, CV, less than 6%), so you do not necessarily gain significant reliability of your results. Also, LC-MS/MS results show very small variations with repeated injections/measurements. The intraassay CV is usually smaller than 5%. As a rule of thumb: The smaller the number of samples in your study is, the better it is to run duplicate assays. If your budget allows for duplicate assays, you may save yourself from annoying queries.

You do not have to add dry ice or cool packs if you only want cortisol and/or amylase assays from saliva samples. Also, no ice or cool packs needed for hair (nail, feather, fur) samples. If you are sending blood, urine, or CSF samples, please ship them on dry ice.

Unfortunately, no. We perform several hundred assays every day and, thus, the offered service fees are at a low, highly competitive rate already. For assay services of a very large number of samples (>2,000), let’s talk…

Depending on the number of samples and the number or requested parameters, you can expect to receive results within 1-2 weeks after sample receipt (up to 1000 samples assayed by immunoassay, up to 500 samples assayed by LC-MS/MS). Provided the backlog of samples in the lab is not very large, we can assay up to 2000-5000 samples per week. If your results even faster, please ask for Express Service. It is always a good idea to announce your shipment ahead of time. Give us 2-3 weeks to include your samples in the lab calendar for rapid assay. Note that due to nature of the assay, hair analysis takes two additional days.

We kindly ask you to email us an excel file with the sample IDs entered in a single column along with your shipment. The assay results will be pasted into your excel file and emailed back to you.

Yes and No – for salivary cortisol levels we have published ‘normal’ values from a large number of samples (>100,000). You can download the paper here. The Rotterdam lab of Yolanda de Rijk has published reference ranges for hair cortisol from a sample of 625 healthy children aged 0-18 yrs in their 2020 paper. In collaboration with other research groups, we have compiled hair steroid hormone data for 5 steroid hormones from over 10,000 hair samples, all assayed with the same LC-MS/MS protocol. The samples came from individuals between 4 and 80+ years of age. You can download a table with the unpublished data here.  Please refer to this as Kirschbaum, personal communication in your paper(s).

Unfortunately, there are no normal data for endocannabinoids available yet.

We usually first perform the assays, email the results to you, and then send an invoice to you or your financial administration. If you need to have a purchase order from your institution, email us the PO number along with your assay order. Payments can be made by money transfer, checks (not preferred), or credit card.

Sure, we can issue an invoice according to your order on short notice.

Sure, if you have received immunoassay salivary amylase and/or salivary cortisol results, feel free to use this paragraph.

If you had received LC-MS/MS analysis for your saliva/blood/urine samples, please cite this paper.

For hair analyses, please refer to the respective publication that describes and evaluates the methodology in greater detail. The LC-MS/MS protocol for endocannabinoid analysis can be found here.