Limitations of Lab Testing


I have three important educational videos to share with you. You will definitely learn some things you didn’t know about each of these tests if you work through this 3-video series.

  • Dutch and 24hr Urine Testing Caveats
  • Saliva Testing Caveats
  • Serum Testing Caveats

We spend a lot of effort conveying the strengths of our dutch testing model to you. In this series we want to focus on the limitations of lab testing. To be fair to other types of testing, we will start with our own. This three part series will help you understand the limitations of urine (including dutch), saliva and serum testing for hormones. This is an attempt to be as transparent and thorough as possible on this topic. We are calling this “The Caveat Series.” Every lab test has some caveats to them. Some are obvious and some are subtle (yet very important). The information below is a written overview of dutch and 24hr urine testing limitations. Two following posts will similarly break down the limitations of saliva and serum hormone testing. If you have any questions on this information, please let me know. Cheers!

An overview of dutch and 24hr urine caveats

Dutch and 24hr Urine Testing Caveats

Urine testing has significant benefits

  • Averages hormone levels of far more time than serum or saliva
  • Offers more metabolites (estrogen, cortisol, DHT, etc.)

What are the disadvantages of urine hormone testing? (watch the video above as these issues can be complex)

  • The methods matter (some methods used are not optimal and quality may differ significantly from lab-to-lab)
  • Testosterone can be falsely low, especially in Asian individuals (complex issue…watch the video for details)
    • Dutch testing improves the detection of this issue, but for those who have it, urine testing is not effective for testosterone monitoring
  • Is difficult to use effectively with oral estrogens and all sublingual hormones due to 1st-pass metabolism

What are the specific disadvantages to 24hr urine collections that can be overcome by dutch testing

  • Patient compliance is an issue because it is so cumbersome (go DUTCH!)
  • One study showed up to 40% of people did the collection wrong
  • Patients must accurately measure the 24hr sample once they are done
  • The diurnal pattern of cortisol is lost
  • Many labs test “total” cortisol, not “free”
  • Melatonin is better measured in our overnight sample (this is a minor distinction)
  • Not effective for oral progesterone. This has nothing to do with the collection. The labs must measure alpha metabolites, not just the standard metabolite.
  • Not effective for vaginal estrogens or testosterone (contamination…dutch removes this!)

What are the specific disadvantages to dutch (as compared to 24hr urine collections)

  • Results are dependent on creatinine excretion being appropriate
    • Not appropriate for people with significant kidney issues
    • If patients excrete creatinine differently than expected levels (for their age, height, weight), it can introduce bias to the testing
  • Collection does not cover the entire 24hrs as with a 24hr collection
    • Results correlate strongly to a 24hr collection, so this is typically not a problem
    • This can be a problem with very specific supplementation scenarios (see video for details) but the issue can be overcome with proper timing of supplementation.

You may notice I did not mention transdermal hormones. I find transdermal to be difficult to monitor well by any method, but that is a long, complex issue that I am still sorting out personally. I did not address it in detail here. I hope you found this information useful in knowing the limitations of urine testing and specifically our dutch testing model. Look for analogous future posts on saliva and serum testing.