ISIL&TIFIL
Member Since 2011
I guess we are going good....knock on wood.... :mrgreen:
The question this vet was responding to involved a low T3 but T4 and free T3 and free T4 were all normal.Christopher A. Lee said:Certain diseases can lead to a reduction in thyroid levels while the thyroid gland itself is functioning normally. How this works: Illness leads to decreased binding of the protein to T4 and T3. With less bound, the free portion increases. As the free form is the biologically active form, the body will then have a "feedback loop" to decrease production of the hormones till the free portion is "normal". This is why dogs with a low T4 but a normal FT4 are not hypothyroid. The diseases possible range from stress, to dental disease, to drugs, to more serious situations.
In this case, the T3 may be artifact (lab error). It just doesn't really fit. Either way, I think your plan of just retesting is a great one. At this point, I wouldn't be too concerned over these values.