Manufacturer and FDA developments on re-calibra... - Thyroid UK

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Manufacturer and FDA developments on re-calibration of FT4 tests



In March Prof L Thienpont went to the USA Federal Drug Administration with the IVD manufacturers, to hear what the requirements will be for FDA clearance for FT4 test re-calibration and consistency after standardization. The requirements are:

1) -Establishment of new reference ranges

2) -Risk-Benefit assessment (to prevent patients being harmed after standardization)

3) -Education/information of clinicians.

We now have the regulatory demands clearly stated. It will take millions of £/$ to put right. Hasn't started yet, and I believe some manufacturers won't be able to comply because of cost.

FT3? The Thienpont group are developing the reference method so not there yet. It is more difficult than for FT4 so needs great care in establishing a good protocol. Watch this space.

9 Replies

I most certainly will watch this space Diogenes. Thank you for this information. Janet.

Hope yet.



Do you think this will cascade over the USA to the UK (and, indeed, the rest of the world)?

If this space gets much more watched it will start blushing. :-)


diogenes in reply to helvella

Yes they will do, especially as the drive for consistency is Europe-based. I'm sure Brussels will take up the cudgels, if only in its own time.

PR4NOW in reply to diogenes

Diogenes, I know Dr. Thienpont said the TSH was not that far out and would take less to harmonize but is the FDA involved in setting a standard or is she just working with the vendors. Are the FT4 and FT3 tests the only ones that the FDA will be involved with because they have the most variance? PR

diogenes in reply to PR4NOW

Prof Thienpont is entirely responsible for setting the standards. Her team is not connected with any manufacturer as a sponsor - the work is entirely independent. FT4 and FT3 tests are the only tests in real trouble because of inconsistency test method to method, FT3 the worst. Rationalizing TSH tests will cost a lot less than for FT4 and FT3. Frankly I feel the chemistry of the various detection methods used by manufacturers is getting in the way uniquely, because FT4/3 tests absolutely demand as natural an environment chemically as possible re Cl, bicarbonate, phosphate, pH, temperature etc. Sometimes the detection chemistry isn't compatible with that and unsatisfactory compromises are made. All other tests aren't as picky.

Something good to come out of Brussels at last! Janet.

Diogenes, I second Rod's question. Are the European regulators going to follow suit? Will they adapt the FDA's standards once they are established? Also what about the standards for TSH, TT4 and TT3? Has the FDA already worked on these? PR

diogenes in reply to PR4NOW

Re total T4 and T3, these have been better standardized quite early on. Reason is that they are easy to do like TSH - don't have the unique demands of chemical environment in which to do the test - as see above for FT4/3 tests

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