LabCorp lowers Serotonin upper limit from 321 ng/mL to 207 ng/mL

[tastyfood]

LabCorp lowered the upper limit for blood serotonin, which I find surprising, knowing the trend is to make the ranges bigger.

Proof of the change from a recent test:

@haidut is this a rare case of a lab like LabCorp lowering the upper limit for one of the harmful hormones by so much?

 

[Elie]

How accurate would serum serotonin be?
Ray once replied to my question, suggesting testing plasma serotonin would be the way to go. Although, I am not aware of any labs that test plasma serotonin

 

[tastyfood]

How accurate would serum serotonin be?
Ray once replied to my question, suggesting testing plasma serotonin would be the way to go. Although, I am not aware of any labs that test plasma serotonin

Great question. What makes me wary about the results is the preparation required for the patient to test it. I did not stop coffee the days before the test, for example. I am not aware of any way to test using plasma either, can't find it. From the LabCorp site:

Preparation:

No fasting required. Avoid food high in indoles such as avocado, banana, tomato, plum, walnut, pineapple, and eggplant. Tobacco, tea and coffee should also be avoided three days prior to specimen collection. Serotonin levels may be affected by certain types of medications such as morphine, MAO inhibitors, methyldopa, and lithium. Check with physician before stopping any medications.

 

[Law]

My guess would be that the proportion of the population captured by the reference range (e.g., middle 95%) remains the same. For instance, the lab may use a different reagent to evaluate the lab specimen. I doubt the changed range reflects a new understanding of the role of serotonin in health.

 

[tastyfood]

My guess would be that the proportion of the population captured by the reference range (e.g., middle 95%) remains the same. For instance, the lab may use a different reagent to evaluate the lab specimen. I doubt the changed range reflects a new understanding of the role of serotonin in health.

Great take. Thanks for your comment!

 

[ironfist]

Like, I didn't even know there was a serotonin bloodtest.

 

[tastyfood]

It's one of the more expensive ones. They take almost a weel to give you the results.

 

[haidut]

While blood serotonin is what Ray recommended, I believe. He said serum serotonin is almost always normal unless somebody has carcinoid syndrome/tumor. The whole blood test is unfortunately usually even more expensive than the serum one since AFAIK the sample has to be frozen as soon as it is collected. and transported in frozen condition to the lab, which means much more expensive shipping.

 

[tastyfood]

While blood serotonin is what Ray recommended, I believe. He said serum serotonin is almost always normal unless somebody has carcinoid syndrome/tumor. The whole blood test is unfortunately usually even more expensive than the serum one since AFAIK the sample has to be frozen as soon as it is collected. and transported in frozen condition to the lab, which means much more expensive shipping.

The collection requirements for whole blood serotonin are wild, no wonder why the direct to consumer labs don't offer it:

From LabCorp:

Sample collection practices that prevent blood clotting and oxidation of serotonin are imperative. Collect three tubes (4 mL each) whole blood. Invert tubes at least ten times to ensure thorough distribution of EDTA. Immediately transfer 10 mL whole blood to transport tube containing 75 mg ascorbic acid. Thoroughly mix by inverting whole blood/ascorbic acid mixture another ten times. Freeze transport tube and send entire collection to the laboratory.