The new Roche Elecsys TSH assay conforms with current IFCC C-STFT standards

[helvella]

If you have recently noticed a change in the TSH range used by the lab with which you are familiar, or do so in the near future, the reason just might be this attempt to standardise TSH tests - including reference intervals - across 14 manufacturers.

(Of course, the manufacturers have been selling their inconsistent tests for many years. So, whilst this might be welcome, I for one am hardly going to go and cheer them on.)

Unfortunately, I can only see the first page of the letter.

It is also unclear from what I can see whether, at long last, all TSH tests have been improved so as not to be affected by macro-TSH, biotin, etc. Nor how long from date of publication to when we can expect these standardised tests to become universal.

Nor is it clear whether we can expect similar standardisation of Free T4, Free T3 and antibody tests.

Letter to the Editor

Juergen Kratzsch, Nikola A. Baumann, Ferruccio Ceriotti, Zhong X. Lu, Matthias Schott, Antonius E. van Herwaarden, Jose Gilberto Henriques Vieira, Holger Lehmann, Dusanka Kasapic and Luca Giovanella*

The new Roche Elecsys TSH assay conforms with current IFCC C-STFT standards

doi.org/10.1515/cclm-2021-0352

Received March 23, 2021; accepted June 29, 2021; published online July 13, 2021

To the Editor, Thyroid-stimulating hormone (TSH) measurements provide a sensitive and specific means of detecting thyroid dysfunction and have a prominent role in the diagnosis and management of thyroid disorders [1]. Unfortunately, TSH results vary between assays from different manufacturers[2]. In addition, reference intervals also vary between assays and the variations are not in-line with the observed analytical differences [3–6]. An international reference preparation (IRP) standard for TSH already exists (WHO Reference Standard 80/558) [7] but a difference of up to20% can still occur in a given sample using different immunoassays. Hence, IRP-traceable TSH assays do not give equivalent or interchangeable results [6, 8, 9]. The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) Committee for Standardization of Thyroid Function Tests (C-STFT) developed a global harmonization approach for TSH measurements, in which14 manufacturers of TSH immunoassays recalibrated their assays in accordance with targets from the IFCC C-STFT [9].Following recalibration, the coefficient of variation of the assay means was reduced from 9.5 to 4.2%, showing a significant improvement in the alignment of results between the 14 TSH assays; furthermore, reference intervals also showed improved uniformity across assays [9]. The Elecsys® TSH Electrochemiluminescence (ECLIA) immuno-assay using the cobas e601 analyzer (Roche Diagnostics GmbH, Mannheim, Germany) was one of the assays included in the IFCC C-STFT Phase IV recalibration study [9]. The aim of this study was to assess the comparability of the current Elecsys TSH immunoassay standardization concept with the proposed IFCC C-STFT harmonization approach, and to evaluate lot-to-lot consistency. First, we evaluated 196 samples from two commercial sources (invent Diagnostica GmbH and Solomon Park Research Laboratories) and eight outpatient thyroid clinics in Belgium, Japan and Australia, provided by the IFCCC-STFT TSH harmonization committee. TSH levels were measured at the Roche Diagnostics Research and Develop-ment laboratory using an Elecsys TSH assay (Lot: 179690;Mat# 11731459122) and master calibrator (Lot: 178959; Mat#04738551190) with the PreciControl Universal V2 level 1 and2 (Lot: 179247/179255; Mat# 11731416190) on a cobas e601analyzer (Roche Diagnostics GmbH, Mannheim, Germany).Samples were first analyzed using calibrator values for the standard Elecsys TSH immunoassay, then using the harmonized target values provided by the IFCC C-STFT [9].The results from the two methods were compared using Passing and Bablok regression [10] with a Roche Diagnostics [available text ends there]

degruyter.com/document/doi/...

diogenes

[diogenes Remembering]

It's about time manufacturers paid attention to standardising assays. TSH was the first to have a rigorous programme of recalibration, but there has been a lot of foot dragging.

[helvella Administrator Thyroid UK in reply to diogenes]

It would also be good if the word "suppressed" were either properly defined or itself suppressed.

I'd prefer "below reliable detection limit" or something like that. Clearly relating it to the technology.

[tattybogle in reply to helvella]

i'm a great fan of the predictive txt version.. "my TSH is surprised"

[tattybogle]

hurray .... all the mapmakers have agreed on the same scale for measuring how flat the earth is ..... but they still haven' t noticed there's a big yellow thing in the sky called T3 that it goes round .. oh well , i suppose every little helps.

[helvella Administrator Thyroid UK in reply to tattybogle]

The single biggest reason to smile, at least a little, is that they can no longer deny the issue exists!

Until we see the results - as in nearly- or fully-standardised results coming out of labs - we have to continue with the same old, same old warning to all.

[jgelliss]

Thank you Helvella. A small dent . Does that Hopefully mean there is going to be work in progress? And benefits for thyroid patients down the pike? That would would be very welcome for

much needed

Improvement.

[helvella Administrator Thyroid UK in reply to jgelliss]

I think it implies they are working on FT4 and FT3.

[jgelliss in reply to helvella]

Even better. I must have miss understood. Now we need Dr's on board too. I guess that can take some time. The truth is Dr's should be taught in the Medical Academia about adding T3 with T4 for those who don't do well enough on T4 sole.