Pituitary adenoma or incidentaloma, anterior pituitary insufficiency (suspected)
BioMG follows French guidelines. Adapt it to the guidelines and the tests available where you practise.
Pituitary adenoma or incidentaloma found on imaging
Laboratory tests in the morning, between 8 am and 9 am
- Serum prolactin (macroadenoma: ask for an assay after dilution, hook effect)
- IGF-1
- TSHif neededTests for deficiency are recommended above all for macroadenomas and microadenomas of 6 to 9 mm, not necessarily for smaller ones [1]. TSH and free T4 are measured together: a normal or low TSH with a low free T4 indicates a pituitary origin [1,2]. The NABM covers TSH + free T4 straight away when suspected central hypothyroidism is stated on the prescription [3].
- Free T4 (write "suspected central hypothyroidism")if neededTests for deficiency are recommended above all for macroadenomas and microadenomas of 6 to 9 mm, not necessarily for smaller ones [1]. TSH and free T4 are measured together: a normal or low TSH with a low free T4 indicates a pituitary origin [1,2]. The NABM covers TSH + free T4 straight away when suspected central hypothyroidism is stated on the prescription [3].
- 8 am serum cortisol (if macroadenoma (10 mm or more), microadenoma of 6 to 9 mm, or sign of deficiency)if neededCorticotroph deficiency in up to 18% of incidentalomas [1]. Baseline serum cortisol between 7 and 8 am; threshold values indicative, dependent on the assay [4].
- LHif needednon-French guidelineGonadotroph deficiency in up to 30% of incidentalomas [1]. Low gonadotrophins in a postmenopausal woman indicate pituitary deficiency; in men, they distinguish central from primary hypogonadism [1].
- FSHif needednon-French guidelineGonadotroph deficiency in up to 30% of incidentalomas [1]. Low gonadotrophins in a postmenopausal woman indicate pituitary deficiency; in men, they distinguish central from primary hypogonadism [1].
- Morning total testosterone (men, if macroadenoma (10 mm or more), microadenoma of 6 to 9 mm, or sign of deficiency)if needednon-French guidelineThe minimum screen proposed by some experts includes free T4, morning cortisol and testosterone [1].
- Oestradiol (premenopausal woman with irregular or absent cycles)if needednon-French guidelineIn the non-menopausal woman, gonadal function is first assessed from the history (cycles) and examination [1].
- Overnight dexamethasone suppression test (if signs of hypercortisolism)if needednon-French guidelineScreening for cortisol excess is suggested in case of clinical suspicion, not routinely, because of many false positives [1]. See the page “Cushing's syndrome”.
Also consider
Do not order
- Routine ACTH: the Endocrine Society expert panel does not recommend routine measurement in an incidentaloma [1].
- TSH alone to look for thyrotroph deficiency: it may be normal; TSH and free T4 are measured together [2].
- Free T3: an isolated low T3 points to non-thyroidal illness, not to central hypothyroidism [2].
Suspected anterior pituitary insufficiency (low free T4 with non-raised TSH, postpartum haemorrhage, head injury, radiotherapy, immunotherapy)
Laboratory tests in the morning, between 8 am and 9 am, without hydrocortisone since the day before
- 8 am serum cortisol
- TSH
- Free T4 (write "suspected central hypothyroidism")
- LH
- FSH
- Morning total testosterone (men)if needednon-French guidelineIn men, a low testosterone with LH and FSH not raised points to pituitary deficiency [1]. See the page “Testosterone deficiency in men”.
- Oestradiol (premenopausal woman, menstrual disorders or amenorrhoea)if needednon-French guidelineAmenorrhoea or failure of the return of periods after delivery is among the signs of Sheehan syndrome [6]; in the non-menopausal woman, cycles first inform on the gonadotroph axis [1].
- Serum prolactin
- IGF-1
- Serum electrolytes (sodium)if needednon-French guidelineIn acute Sheehan syndrome, adrenal insufficiency may present as hypotension, hypoglycaemia and hyponatraemia [6].
Do not order
- TSH alone to screen for or follow central hypothyroidism: TSH may be normal; measure TSH and free T4 together [2]. On levothyroxine, TSH is no longer used to adjust the dose: aim for a free T4 in the upper half of normal [2].
- Free T3: an isolated low T3 does not indicate central hypothyroidism [2].
- Routine hormonal screening after mild head injury without suggestive symptoms [7].
Sources (9)
- Freda PU, Beckers AM, Katznelson L, Molitch ME, Montori VM, Post KD, et al. Pituitary incidentaloma: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011;96(4):894-904.
- Persani L, Brabant G, Dattani M, Bonomi M, Feldt-Rasmussen U, Fliers E, et al. 2018 European Thyroid Association (ETA) guidelines on the diagnosis and management of central hypothyroidism. Eur Thyroid J. 2018;7(5):225-37.
- Assurance maladie. Nomenclature des actes de biologie médicale (NABM), version 105 : actes 1208 (TSH), 1211 (TSH + T4 libre), 0462 (cortisol), 0343 (prolactine), 0780 (IGF-1).
- Chanson P, Guignat L, Goichot B, Chabre O, Samara Boustani D, Reynaud R, et al. Groupe 2 : Comment dépister et confirmer le diagnostic d'insuffisance surrénale ? Consensus SFE/SFEDP sur l'insuffisance surrénale (version française de : Ann Endocrinol (Paris). 2017;78(6):495-511).
- Fleseriu M, Gurnell M, McCormack A, Fukuoka H, Glezer A, Langlois F, et al. Pituitary incidentaloma: a Pituitary Society international consensus guideline statement. Nat Rev Endocrinol. 2025;21(10):638-655.
- Karaca Z, Kelestimur F. Sheehan syndrome: a current approach to a dormant disease. Pituitary. 2025;28(1):20.
- Quinn M, Agha A. Post-traumatic hypopituitarism: who should be screened, when, and how? Front Endocrinol (Lausanne). 2018;9:8.
- National Institute for Health and Care Excellence (NICE, Royaume-Uni). Adrenal insufficiency: identification and management. NICE guideline NG243, 28 août 2024.
- National Institute for Health and Care Excellence (NICE, Royaume-Uni). Head injury: assessment and early management. NICE guideline NG232, 18 mai 2023.