For more information of Thyroid in Pregnancy please see Thyroid Conditions and Pregnancy
Interpretation of Thyroid Function Tests – CHANGES OCTOBER 2021.
Following the transition to Roche automated laboratory equipment there has been associated changes in reference values for all thyroid function tests. Based on comparative studies, clinical biochemistry predict there may be a greater instance of patients with apparent high free T4 but normal TSH, particularly in patients treated with thyroxine.
Roche themselves indicate a separate free T4 reference range for ‘patients on thyroxine treatment with euthyroid TSH’ of 14-28 pmol/L. Please consider this and interpret the results of free T4 and TSH measurements together alongside clinical findings before considering referral to endocrinology.
Information
General thyroid disease will be seen in the endocrine clinics at RIE, WGH and SJH. Please see the Referral guideline Section for information on who should be referred for specialist care and who is appropriate for management in primary care. Advice can be sought on any thyroid question by selecting the ‘Advice only’ option on SCI Gateway
Patients with suspected thyroid cancer and euthyroid patients with goitres should be referred to the thyroid nodule clinic at RIE via SCI Gateway.
Patients with suspected thyroid eye disease should be referred to the joint thyroid eye clinic via Dr Justine McKee at PAEP. They will receive both ophthalmic and endocrine follow-up at this clinic, but if the patient requires endocrine input, it is advisable to send a duplicate referral to RIE endocrinology selecting the ‘Advice only’ option and marking the referral for the attention of Dr Anna Dover or Dr Nicola Zammitt. Please see resources and links for information on how urgently they should be referred depending on their signs and symptoms.
Please note that none of the endocrinologists in the Edinburgh Centre for Endocrinology will prescribe desiccated thyroid extract (also known as DTE, natural desiccated thyroid, NDT or Armour thyroid), in line with advice from the British Thyroid Association. Please see the British Thyroid Association statement on the management of hypothyroidism.
Who to refer:
Thyrotoxicosis
All cases of thyrotoxicosis should be referred to an endocrinologis
- The lab will automatically add TSH Receptor Antibodies (TRAbs) to all new thyrotoxic bloods
- No further investigations are needed prior to referral
- If patients are very symptomatic, consider treatment with propranolol 40mg tds, or with a rate-limiting calcium channel blocker, such as verapamil, if beta-blockade is contraindicated.
- Many consultants will provide advice on treatment when triaging a new patient with Graves’ disease. However, if there is concern that the patient is significantly unwell (e.g. significant tachycardia, uncontrolled AF) advice on initial management can be provided by paging the on call endocrine registrar at RIE or WGH.
Hypothyroidism
Straightforward hypothyroidism can usually be managed in primary care but we are happy to offer advice (select ‘Advice only’ on SCI Gateway) or see cases that may not be straightforward, for example:
- Hypothyroidism during or within 12 months of pregnancy (this may be a transient thyroiditis)
- Cases where there is diagnostic uncertainty
- History of neck pain, systemic upset or earlier thyrotoxic symptoms suggesting transient thyroiditis
- TSH <20, particularly if there is a suspicion of pituitary pathology
- Cases associated with amiodarone or lithium therapy
Goitres and nodules
Thyroid nodules, particularly when solitary and clinically obvious should be investigated, as they carry a small but significant malignant potential (up to 10%). Thyroid function tests should be requested by the GP and appended to the referral letter. Hyper– or hypothyroidism associated with a nodular goitre are unlikely to be thyroid cancer; these patients should be referred to a general endocrine clinic. Initiation of other investigations (such as ultrasound scanning or autoantibodies) are unnecessary and may cause delay in making the diagnosis of cancer. Please see the primary care guidance on thyroid nodules.
Immediate (same day) referrals: Patients with stridor associated with a thyroid swelling should be referred immediately to the Thyroid Surgery Service (Call 0131 242 1715/4).
Urgent referrals for suspected cancer: The presence of the following symptoms or signs in association with a thyroid swelling may indicate more aggressive or advanced disease and should be referred urgently:
- Unexplained hoarseness or voice change
- Thyroid Nodule/goitre in a child
- Cervical lymphadenopathy associated with a thyroid lump (usually deep cervical or supraclavicular).
- A rapidly enlarging painless thyroid mass over a period of weeks (a rare presentation of thyroid cancer and usually associated with anaplastic thyroid cancer or thyroid lymphoma).
Patients with a history of sudden onset of pain in a thyroid lump (likely to have bled into a benign thyroid cyst) or a thyroid lump that has newly presented or has been increasing in size over several months should be referred to the Thyroid Nodule Clinic.
Euthyroid patients with a goitre should also be referred to the ‘Thyroid Nodule Clinic.
Thyroid eye disease
If you think a patient has dysthyroid eye disease, they should be referred the joint thyroid eye clinic via Dr Justine McKee at PAEP. They will receive both ophthalmic and endocrine follow-up at this clinic, but if the patient requires endocrine input, it is advisable to send a duplicate referral to RIE endocrinology selecting the ‘Advice only’ option and marking the referral for the attention of Dr Anna Dover or Dr Nicola Zammitt. Please see advice on the urgency of referral depending on symptoms and signs in resources and links. advice on the urgency of referral depending on symptoms and signs. Patients in West Lothian should be referred to Dr Jan Kerr in ophthalmology. Prior to referral, please check TFTs (TSH, FT4 and TT3) and TRAb titres, stating the suspicion of thyroid eye disease on the request. Patients may have Graves’ eye disease despite being hypothyroid or even euthyroid. The referral can be sent before results are available.
Who not to refer:
Hypothyroidism
Patients with straightforward primary hypothyroidism with positive anti-thyroid peroxidase antibodies and none of the features of diagnostic uncertainty highlighted in the ‘Who to refer’ section do not need further investigation or referral to endocrinology. Treatment with levothyroxine can be managed in primary care.
Asymptomatic patients with subclinical hypothyroidism (FT4 normal and TSH <10) do not usually require treatment with levothyroxine. Advice can be requested using the ‘Advice only’ option on SCI Gateway. Please see guidance on TFTs in primary care.
Please see the Resources and Links page for advice about testing and management of nodules and eye disease in Primary Care.
Hypothyroidism
Patients with straightforward primary hypothyroidism with positive anti-thyroid peroxidase antibodies and no features of diagnostic uncertainty (see ‘Who to refer’) do not need further investigation or referral to endocrinology. Treatment with thyroxine can be managed in primary care. Please see resources and links for information on Thyroid function testing in primary care (including pregnancy)
Asymptomatic patients with subclinical hypothyroidism (FT4 normal and TSH <10) do not usually require treatment with levothyroxine. Advice can be requested using the ‘Advice only’ option on SCI Gateway. Please see resources and links for guidance on TFTs in primary care.
Goitres and nodules
Thyroid function tests should be requested by the GP and appended to the referral letter. Hyper– or hypothyroidism associated with a nodular goitre is unlikely to be thyroid cancer; these patients should be referred to a general endocrine clinic. Initiation of other investigations (such as ultrasound scanning or autoantibodies) are unnecessary and may cause delay in making the diagnosis of cancer. Please see resources and links for a primary care guide on Thyroid nodules.
2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum https://www.liebertpub.com/doi/pdfplus/10.1089/thy.2016.0457
Clinical Guidance
- Thyroid Function Testing in Primary Care Guidance
- Who to refer to Ophthalmology
- Picture guide to clinical activity in Thyroid Eye Disease
- BTA Hypothyroidism Statement
- BTA and BTF updated information on T3 plus T4
Thyroid Patient information leaflets
The ECED website has some patient information on Graves’ Disease. This can be accessed on the following link:
www.edinburghdiabetes.com/graves
Excellent patient information leaflets are provided by the British Thyroid Foundation (BTF). Patients can be directed to look at these on-line or individual leaflets can be printed from the website. The BTF will also send out larger volumes of specific information leaflets, although this requires a payment. Details are on their website and leaflets can be accessed on the following link:
http://www.btf-thyroid.org/information/leaflets
Patient information on thyroid eye disease can also be found on the Thyroid Eye Disease Charitable Trust (TED-CT) website, which can be accessed on the link below: