Dr Justin Saya MD
Moderator
When evaluating ratios, one must always take into account the units of measurement of the two components of the ratio (which will typically be different units). For example, through LabCorp, free T3 is reported in units of pg/mL (range 2.0 - 4.4 pg/mL) and reverse T3 is reported in units of ng/dL (range 9.2 - 24.1 ng/dL).
So, when saying, as the STTM folks always tout, that a 20:1 ratio is ideal folks have to make sure to convert to the same units. However, the "calculator" on the STTM site ( http://www.stopthethyroidmadness.com/rt3-ratio/ ) that calculates these ratios is flawed (it doesn't calculate correct ratios...it even states it is a beta calculator...I've had some patients rely on that calculator and come to false conclusions). You can even verify it miscalculates by converting units manually and calculating the ratios or by using the conversion calculator they suggest:
http://www.mens-hormonal-health.com/hormone-unit-conversion-calculator.html
Jackie Treehorn - your Free T3 : 4.0 pg/mL -- (upper end of range 2.0-4.4 pg/mL) compared to your reverse T3 : 10.6 ng/dL (lower end of range 9.2 - 24.1 ng/dL) is indeed a GOOD ratio...you want free T3 upper range with reverse T3 lower range.
HOWEVER, when converting units:
Free T3 4.0pg/mL converts to 0.4 ng/dL, then when plugged in to a ratio with reverse T3 at equivalent units (pg/mL) one gets:
Free T3: reverse T3 = 0.4 ng/dL : 10.6 ng/dL = ratio of 0.037.
Works the same if you just convert the units to both be pg/mL --> reverse T3 10.6 ng/dL converts to 106 pg/mL. And recall free T3 is already in pg/mL units at 4.0 pg/mL. Thus, the ratio:
Free T3: reverse T3 = 4.0pg/mL : 106 pg/mL = ratio of 0.037.
I think the ratio "theory" (and especially the faulty calculator) along with the complexity of unit conversion cause many folks more confusion than good when attempting to evaluate these numbers.
For sanity's sake, when evaluating these ratios, follow this principle:
You want Free T3 on UPPER end of range generally, with reverse T3 on LOWER end of range generally...but there are MANY other layers of complexity just as with the sex hormones.
So, when saying, as the STTM folks always tout, that a 20:1 ratio is ideal folks have to make sure to convert to the same units. However, the "calculator" on the STTM site ( http://www.stopthethyroidmadness.com/rt3-ratio/ ) that calculates these ratios is flawed (it doesn't calculate correct ratios...it even states it is a beta calculator...I've had some patients rely on that calculator and come to false conclusions). You can even verify it miscalculates by converting units manually and calculating the ratios or by using the conversion calculator they suggest:
http://www.mens-hormonal-health.com/hormone-unit-conversion-calculator.html
Jackie Treehorn - your Free T3 : 4.0 pg/mL -- (upper end of range 2.0-4.4 pg/mL) compared to your reverse T3 : 10.6 ng/dL (lower end of range 9.2 - 24.1 ng/dL) is indeed a GOOD ratio...you want free T3 upper range with reverse T3 lower range.
HOWEVER, when converting units:
Free T3 4.0pg/mL converts to 0.4 ng/dL, then when plugged in to a ratio with reverse T3 at equivalent units (pg/mL) one gets:
Free T3: reverse T3 = 0.4 ng/dL : 10.6 ng/dL = ratio of 0.037.
Works the same if you just convert the units to both be pg/mL --> reverse T3 10.6 ng/dL converts to 106 pg/mL. And recall free T3 is already in pg/mL units at 4.0 pg/mL. Thus, the ratio:
Free T3: reverse T3 = 4.0pg/mL : 106 pg/mL = ratio of 0.037.
I think the ratio "theory" (and especially the faulty calculator) along with the complexity of unit conversion cause many folks more confusion than good when attempting to evaluate these numbers.
For sanity's sake, when evaluating these ratios, follow this principle:
You want Free T3 on UPPER end of range generally, with reverse T3 on LOWER end of range generally...but there are MANY other layers of complexity just as with the sex hormones.