Clinician reference tool — not medical advice. This is a clinical decision-aid intended for healthcare professionals: it gives deterministic suggestions to think with, not a diagnosis or a prescription. If you’re a patient, you’re welcome to look around — but please review anything here with your own doctor; it isn’t a substitute for personalized medical care.
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Prolactin

Sex hormones · specimen: blood

Indicated in specific situations

Also called: serum prolactin, PRL, prolactin level, hyperprolactinemia test

Chart note

Pick Ordered or Not ordered to see the note.

Indicated when

  • Irregular or absent periods, or other features prompting a PCOS work-up, where prolactin is checked to exclude hyperprolactinaemia as the cause of the same clinical picture before attributing it to PCOS [1]
  • Galactorrhea (spontaneous nipple discharge), or other symptoms that raise concern for a prolactin-secreting pituitary tumour, where the Endocrine Society's hyperprolactinemia guideline is the reference for diagnosis and management [2]

Not indicated when

  • Included in a general wellness or hormone panel with no menstrual, galactorrhea, fertility, or pituitary symptoms present

Why not

Outside these situations, prolactin has no established screening role, so testing it as part of a routine panel mainly risks finding a mildly elevated result that needs a repeat draw or further work-up to interpret, rather than changing management [2].

Better first step

Take a focused history for menstrual pattern, galactorrhea, fertility concerns, pituitary symptoms (headache, visual change), and medications known to raise prolactin, and order prolactin when one of these is present rather than including it in every hormone panel [2, 1].

Typical ND rationale

An ND may include prolactin in a hormone panel for a patient with irregular cycles, fertility concerns, or low libido, reasoning that an elevated prolactin is a treatable and easily missed cause of these symptoms that is worth ruling out early.

Where the ND is right

The ND is right to test prolactin in amenorrhea, irregular cycles, or galactorrhea: this is exactly the differential-diagnosis role prolactin plays before a PCOS diagnosis is made, and it is the recommended test whenever hyperprolactinaemia is a real possibility [1, 2].

Ontario coverage & CONO orderability

OHIP status
insured
Prolactin is listed by name (L332) in the 2026 Schedule of Benefits for Laboratory Services, insured when a physician who has clinically assessed the patient orders it. The same test ordered by an ND is patient-paid regardless (Reg. 552 s.22).
CONO orderable
Yes — CONO list #103
CONO list item 103, blood: 'Prolactin.'

Linked conditions

Counselling script

“If you have irregular or missing periods, nipple discharge, or another symptom that fits with a prolactin problem, checking prolactin is a sensible part of the work-up, so I'll order it today. Without those features, adding prolactin to a general hormone panel isn't something the evidence supports, so I won't order it just to be thorough. If it does come back high, we'll repeat it and look for a cause, including medications, before considering imaging.”

Revisit if

  • New irregular or absent periods
  • Galactorrhea (nipple discharge)
  • New headache or visual field change
  • Starting a medication known to raise prolactin (e.g. antipsychotics, metoclopramide)

References

  1. [1]International PCOS Network (2023). Recommendations From the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome. linkProlactin is one of the tests used to exclude other causes (hyperprolactinaemia) before diagnosing PCOS
  2. [2]Endocrine Society (2011). Diagnosis and Treatment of Hyperprolactinemia: An Endocrine Society Clinical Practice Guideline. linkolder guidelineThe Endocrine Society's clinical practice guideline for diagnosis and treatment of patients with elevated prolactin levels
  3. [3]Ontario Ministry of Health (2026). Ontario Health Insurance Plan: Schedule of Benefits for Laboratory Services (effective April 1, 2026) - L332 Prolactin. linkProlactin (L332) is listed by name in the 2026 OHIP Schedule of Benefits for Laboratory Services
  4. [4]Government of Ontario (e-Laws) (2026). Health Insurance Act, R.R.O. 1990, Reg. 552: General, s. 22 (insured laboratory services). linkA lab test is insured only when ordered by a physician, midwife, or NP who has clinically assessed the patient
  5. [5]Ontario Ministry of Health (2026). Ontario Health Insurance Plan: Schedule of Benefits for Laboratory Services (effective April 1, 2026). linkTests ordered by anyone other than an authorized provider, including NDs, are not insured services
Evidence notes

The Endocrine Society 2011 hyperprolactinemia guideline (Melmed) is not open access; only its PubMed abstract could be quote-verified this session (fetch of the full article returned HTTP 403). The abstract confirms the guideline's scope (diagnosis and treatment of elevated prolactin, including drug-induced hyperprolactinemia and management in pregnancy) but does not itself spell out the specific symptom trigger list used above (galactorrhea, amenorrhea, pituitary symptoms) or the macroprolactin/assay 'hook effect' caveats relevant to interpreting a high result; those reflect standard endocrinology teaching consistent with the guideline's known content but are flagged here as unverified-this-session rather than asserted as guideline text. Flagged older_than_10y (2011); no more recent Endocrine Society update was found. linked_conditions includes Low sex drive or 'low testosterone' in women because hyperprolactinaemia is a recognized, treatable cause of low libido via secondary hypogonadism, though this specific link was not independently sourced this session.