Researchers have shown that analyzing dried urine extracts with GC-MS/MS to assess levels of reproductive hormones in pre-and post-menopausal women provides similar results to radioimmunoassays using serum samples.
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They also showed that collecting four urine samples throughout the day (the 4-spot method) is a suitable substitute for a 24-hour urine collection. These findings could provide an alternative and more convenient collection method for the reproductive hormone analysis that is commonly carried out in epidemiological studies, clinical research and patient care.
The research was published February 4th in the open access journal BMC Biochemistry.
Measuring serum or plasma estrogen and progesterone levels provides similar information about ovarian steroid production to measuring metabolite levels of the hormones in urine.
For analysis of monthly hormone patterns (menstrual cycle mapping), analyzing the first urine sample of the day is usually sufficient, but to assess hormones that may have a circadian rhythm (changes over the course of a 24-hour period) a sample collection that is representative of the entire day is often needed.
Given that dried filter paper samples are easy to collect and transport, it has been suggested that using dried urine extracts as a sampling method could increase study participation rates, compared with conventional methods.
For the current study, lead author Mark Newman (Precision Analytical Inc.) tested whether the DUTCH method developed at his lab for analyzing urinary steroid metabolites from dried filter paper samples could provide comparable information to that obtained through standard radioimmunoassay (RIA) measurement of serum hormone levels.
Urinary assays are a viable alternative to serum analysis
The team used 52 stored blood and urine samples taken from four pre-menopausal and eight post-menopausal women that had previously been collected during a prospective observational study carried out between February and November of 2015.
Newman and colleagues report that measurement of estradiol and progesterone metabolites in dried urine samples using gas chromatography with tandem mass spectrometry (GC–MS/MS), provided similar menstrual cycle mapping to that obtained when serum hormone concentrations were measured using standard RIA.
In a second study involving 26 individuals, the team compared samples taken using the 4-spot method with those taken using a 24-hour collection. For the 4-spot method, samples were collected at four points during the day that spanned 10 to 14 hours of the 24-hour period.
The team found that evaluation of intraclass correlations (ICCs) indicated an almost perfect agreement between the 4-spot collection technique and the gold standard 24-hour urine collection.
The urine results showed substantial agreement with serum results based on intraclass correlations (ICC) for the group of premenopausal and postmenopausal women for all metabolites supporting use of the urinary assay as a substitute for serum analysis.”
Dried urine is a ‘good surrogate’ for serum testing
The authors say their data show that the dried urine assay is a good surrogate for serum testing of reproductive hormones in premenopausal and postmenopausal women. Furthermore, the 4-spot collection technique accurately represents results from a full 24-h urine collection and would, therefore, provide an alternative and convenient sampling method.
Newman and team also recommend that further validation studies of the dried urine method should include 24-h correlation and serum correlation for additional hormones or hormone metabolites.
Finally, they point out that the dried urine assay is useful for certain assessments of hormone disorders and that the ease of sample handling could be beneficial in large epidemiologic studies.
In a YouTube video, Mark says:
When you look at the landscape of hormone testing that’s available – saliva, serum or blood testing and 24-hour urine testing, they each have pieces of information about your reproductive or adrenal hormones that’s missing. The [DUTCH] testing model was developed to bring all of this into one test.”
Mark Newman, Precision Analytical