Thursday, June 30, 2011

Q & A: Trouble Converting Cortisol Units

Cortisol
I am having the hardest time converting units for cortisol measurement. Can you help me with this conversion?

If the laboratory is reported the cortisol results in ng/ml, how do I convert to μg/dl? For example, if the lab has reported a cortisol measurement of 28.2 ng/ml, is that result equal to 2.82 μg/dl?

My Response:

Your conversion is correct. If you are interested, the  mathematical formula for future conversions is as follows:
  • 28.2 ng/ml x 1 µg/1000 ng x 100 ml/1 dl = 2.82 µg/dl

There are many online sites that can help us do these conversions. Here's a web site that I have found helpful.

Personally, I had more difficulty in remembering how to convert traditional endocrine units commonly used in the UA to Standard International (SI) or molar units that some laboratories use to report hormone results. The calculator offered by Veterinary Information Network (VIN) is by far the best I've found (click here to use their calculator).

2 comments:

Anusha G K said...

How can I convert reports on cortisol level expressed in micrograms/dl in terms of nmol/l?

Dr. Mark E. Peterson said...

Multiply the cortisol units in µg/dl by 27.59 to get the result expressed as nmol/L.