You didn't mention your current med and dosage; however, just looking at your test results doesn't show any compelling reason to switch to NDT at this time. Your Free T4 is at 27% of its range and your Free T3 is at 25% of its range. The usual reason to switch to NDT type thyroid med is when the patient's body is not adequately converting T4 to T3. So far there is no evidence of that, even though one of the factors that affect conversion (ferritin) is way too low.
So, at this point I would look for an increase in your T4 med in order to get your Free T4 up to at least the middle of its range and then see if your Free T3 level increases accordingly. Optimal for most people seems to be for Free T4 at the middle of its range, at minimum and Free T3 in the upper third of its range, as needed to relieve symptoms. If you find that you need to raise your Free T3 separately you can just add some T3 to your med. That way they can be adjusted independently. NDT does not seem to offer anything special beyond using a combination of synthetic T4 and T3.
If for some reason you are completely sold on switching, make sure to substitute one grain of NDT for every 66 mcg of T4. And if you do that don't make the switch all at once. I say that because T4 has a much longer half life than T3. So your T4 med would dissipate over a 4 week period, but the T3 would reach full effect in about 4 days.
Also for optimum effect you need to supplement with D3 to raise your level to about 55 minimum. Also if fatigue is a symptom it would be good to raise your B12 into the very upper end of its range. Ferritin level is very important and should be about 70 minimum, so you need to supplement with a good form of iron like ferrous bisglycinate, or ferrous fumarate, or ferrous sulfate. I would start with about 25 mg daily, along with some Vitamin C or magnesium to prevent stomach issues. Then you will need to increase your dosage to probably 50 or 75 mg to adequately raise your ferritin level.
Thanks for your reply. I put the reference range in brackets.
fT4 = 10.4 (8-17)
fT3 = 2.6 (2.0 -4.4)
Anti-TPO = 139 (Negativ 60)
Tg-AB = 63 (Negativ 115)
TSH = 0.82 (0.35 – 4.5)
Vit D3 = 27 (20 – 150)
B12 = 618 (211 – 911)
Ferritin = 13 (13 – 150)
Please post the reference ranges shown on the lab report for those test results.