Hi all,
In my previous post I pointed out my Thriva TSH and FT4 blood test result was much higher than the NHS venous blood test done week before.
Thriva TSH 2.19 (0.27-4.20), NHS 0.76 (0.35-4.78)
Thriva FT4 14.4 (12-22), NHS 16.3 (10-20)
Here is their response to my email where I raised this.
We have previously spoken to our laboratory about the difference in TSH results. (I assume it happens regularly)
The lab we use explained that different laboratories, may use different testing platforms so the mean values of TSH can vary however they should be consistent and reproducible. They explained that the laboratories need to maintain the standards set out in ISO15189 if the lab is accredited. They suggested that check the status of the NHS laboratory, as many are struggling to get ISO15189. Certainly TSH levels can vary, so only two tests done together within a day of each other are comparable.
The laboratory also mentioned that the of day that the sample is taken can have a big impact but I can see that you're aware of this as you mentioned running the tests under the same conditions.
Our labs also suggested that it might be helpful to find out what testing platform the NHS lab uses to see how if it does run lower than the one they use. For reference your blood was tested by County Pathology on our behalf.
What would you infer from this? What does testing platform mean? I am not sure of validity and accuracy of Thriva test. However, I am having a free re-test so shall see.