In this section
Katharine Hayden, Consultant Clinical Biochemist
September 2024
Following GIRFT (Getting It Right First Time) recommendations and discussions with the Associate Medical Directors from Manchester and Trafford localities, we have introduced a new TSH-only profile in ICE from the beginning of September, for use in adult patients on levothyroxine treatment for primary hypothyroidism. For these patients, there is no need to measure FT4, as the goal of therapy is to restore well-being and normalise the serum TSH (NICE guideline NG145 (2019) Thyroid disease: assessment and management).
Background
GIRFT is a national NHS England programme designed to improve the treatment and care of patients through in-depth review of services, benchmarking and the use of a data-driven evidence base to support change. Clinically-led reviews of specialties combining Model Hospital data aim to identify areas of unwarranted variation in clinical practice and/or divergence from best evidence.
The GIRFT Pathology Deep Dive took place at Manchester University NHS Foundation Trust and was attended by clinical representatives from the Emergency Department and General Practice/MHCC/Trafford in addition to laboratory representatives. One of the actions for Biochemistry was to review GP test profiles for thyroid function tests, which then included both TSH and FT4 as first line tests.
GIRFT data showed that a median of 20% GP thyroid profiles nationally contained both a FT4 and TSH compared to 80% TSH-only or a combination of the two testing profiles.
Some centres across England use a TSH-only first line test of thyroid function for all patients in primary care. A number of papers have identified that this approach will miss patients with hypopituitarism and other, albeit rare, conditions such as TSH-oma.
Change to requesting
To remove the risk of missing these potential diagnoses, but to move in line with best practice across the country, it was agreed that a new thyroid function test profile would be created in ICE to include TSH-only for use in monitoring of adult primary hypothyroid patients on levothyroxine replacement.
The existing GP thyroid function test profile including TSH and FT4 as first line tests will continue to be available on ICE for diagnosis as well as for on-going management of hyperthyroidism, hypopituitarism and thyroid cancer, and for children taking levothyroxine for primary hypothyroidism, in line with NICE guidance.
In ICE, when thyroid function testing is requested in an adult patient, a series of pop-up questions now follows to determine whether the TSH-only profile is suitable for your patient.
• Is the patient known to have hypothyroidism Yes/No
• Is the patient pregnant Yes/No
• Does the patient have thyroid cancer Yes/No
• Does the patient have secondary hypothyroidism (hypopituitarism) Yes/No
Stating YES that the patient is known to have Hypothyroidism and NO to the following questions will enable the TSH-only profile to be requested.
The additional questions should not be answered YES if these clinical scenarios do not apply as these questions form part of the patient record and can lead to the incorrect interpretation of results which could cause confusion and distress for patients.
This should not be used as a route to obtain the TSH and FT4 result on a patient undergoing levothyroxine monitoring for primary hypothyroidism. Any clinical concerns regarding testing for a patient can be discussed with the duty biochemist as required.