Help with interpreting reverse T3

I have received my Free T3 and Reverse T3 and would appreciate some help in understanding the ratio.

Free T3 5.8 (3.1 - 6.8 pmo1/L)

Reverse T3 27.9 (9 -35 ng/dl)

Using this calculator: (Stop the Thyroid calculator did not have the conversion I needed)

My result came back as 0.013516599782802224

What does this mean? I have read 2 is meant to be a healthy ratio?

Any suggestions?

Thank you

6 Replies

  • Sorry I can't help you but thinking of having the same test. How/where did you get yours done?

  • I see a doctor who practises functional medicine. My bloods were sent to "The Doctors Laboratory" but I think Genova would run this test

  • Thanks Nik07

  • The STTM book gives this advice:

    1. If both RT3 and Free T3 are in pmol/L or pg/mL, multiply the free T3 by 1000, divide the Free T3 by the RT3.

    2. If theRT3 is nmol/L and Free T3 is pmol/L, divide the Free T3 by the RT3.

    3. If the RT3 is ng/dL and Free T3 is pg/dL, divide the Free T3 by the RT3.

    4. If the RT3 is pg/mL and Free T3 is pg/dL, multiply the Free T3 by 100, then divide Free T3 by RT3.


  • Thanks Hypoteq, it seems that the measurements used by the lab do not feature in the STTM which is most frustrating.

  • You can get a conversion calculator for just about anything at

    or just type the conversion you want into a search engine and it'll take you there

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