I have a question on how to correctly diagnosis an abnormal TSH level. EX: we order a GHP and if the TSH comes back abnormal we then order a Free T4 , what would we use for the Free T-4 (the patient does not have hyper or hypo thyroidism or the GHP dx would not qualify for the Free T4 dx ) . I've been looking at 790.99 or V77.0 ; I've read other posts that were related this question and they suggested 790.6 saying its part of a blood chemistry-which i think is incorrect because the ICD 9 book states the blood chemistry levels, and 794.5 / 794.6 is for function studies. Can I get other peoples' input? Thank you very much in advance!