Research

Hormonal

The BodyTime assay, which estimates internal circadian time from a single blood sample using a small set of transcript biomarkers, achieves accuracy comparable to the gold standard dim-light melatonin onset (DLMO) method while being significantly less costly and time-consuming.

If you are interested in optimizing the timing of medications or health interventions (chronotherapeutics), you can now determine your internal circadian phase with a single blood test (BodyTime assay). This test is as accurate as the traditional gold standard (melatonin testing) but is much faster, cheaper, and does not require special lighting conditions. This allows for personalized timing of treatments based on your unique biological clock.

GoodSupportsHIGH confidence
Our BodyTime assay uses a small set of blood-based transcript biomarkers to compute internal time with an accuracy equaling that of the current gold standard method at a smaller monetary and time cost.
Nicole Wittenbrink et al. · Journal of Clinical Investigation · 2018

Why this rating

The study uses a rigorous 3-stage biomarker development strategy with internal cross-validation and external validation on an independent cohort of 28 subjects, showing high correlation (r >= 0.9) with DLMO.

Source

High-accuracy determination of internal circadian time from a single blood sample

Nicole Wittenbrink et al. · Journal of Clinical Investigation · 2018

DOI 10.1172/jci120874

cohort · n=40Cited 267×
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DOI resolved against Crossref · corpus check 2026-06-10

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