Reasoning GP · Algorithm · 1-page summary
Hypercalcaemia in adults
For: adults with a raised albumin-adjusted calcium (>2.6 mmol/L), in hours or OOH. Not for: children and young people (paediatric or endocrine advice; adult thresholds do not apply); pregnancy (endocrine and obstetric specialist advice; no cinacalcet or bisphosphonates); hospital treatment (full algorithm, step 7).
Core rule: act on the laboratory's albumin-adjusted calcium, read with symptoms, renal function and previous values. Above 3.5 mmol/L is an emergency however well the patient seems; symptoms and rate of rise override the number. Then the paired PTH splits the cause — never file a raised calcium as "borderline" with no PTH and no reviewer.
0Stop — emergency admission now — 999 or immediate discussion with the acute team
- Adjusted Ca²⁺ >3.5 mmol/L, however well the patient seems (risk of dysrhythmia and coma) → 999
- Any level with confusion, coma, seizure, serious arrhythmia, severe dehydration, AKI, persistent vomiting or inability to maintain intake → 999
- Substantial rise on previous results with symptoms, AKI, dehydration, arrhythmia, known malignancy or poor intake; digoxin with arrhythmia or toxicity concern → 999
- While waiting: ECG; hold ACE inhibitor, ARB, NSAID, diuretic, metformin as appropriate and record it. No IV fluids in the community; no loop diuretic. Hand over adjusted calcium, albumin, previous values, U&E, drugs, observations, conscious level, fluid status.
1Triage by adjusted calcium — mmol/L; >3.5 is block 0
| Adjusted Ca²⁺ | Action |
|---|---|
| 3.0–3.5 | Same-day face-to-face assessment or specialist discussion; hospital if symptomatic, rising fast, dehydrated, AKI, malignancy, abnormal ECG, vomiting or poor intake. |
| <3.0, symptoms | Same-day assessment. |
| <3.0, well | Repeat adjusted calcium (≥2.6, or ≥2.5 with PHPT features) — excludes spurious; PTH once raised twice, or in parallel if urgent. Never defer PTH six months. |
2Screen — one row is enough
- Known or suspected malignancy → Same-day oncology or acute; palliative: that team and the patient's wishes decide.
- Myeloma or cancer feature: unexplained bone or back pain, minimal-trauma fracture, anaemia, weight loss, renal impairment, raised ESR/PV, or ≥60 with no parathyroid cause → 48-hour panel: FBC, calcium, ESR/PV, electrophoresis and serum free light chains; suggests myeloma → suspected cancer pathway (NG12).
- Suppressed PTH, no obvious cause → Urgent parallel work-up (block 4); concerning or malignancy features → Same-day
- Adrenal insufficiency: postural hypotension, weakness, low sodium → Same-day; shocked or unwell → 999
3Assess — face to face; not by telephone
☐ GCS, orientation; lying and standing BP, pulse, mucous membranes, skin turgor, urine output ☐ Breast lump, chest, nodes, abdominal mass, bone tenderness, goitre ☐ ECG if symptomatic, ≥3.0 or rapidly rising — no fixed QTc cut-off ☐ Intact PTH paired with adjusted calcium (random, no fasting), albumin, U&E, phosphate, magnesium, ALP, 25-hydroxyvitamin D, FBC, ESR/PV, LFTs, TSH; electrophoresis and free light chains if ≥60
Not routine in primary care: ionised calcium, ACE, PTHrP, 1,25-dihydroxyvitamin D, localisation imaging.
4Classify by PTH — only once urgency is settled
- PTH raised or non-suppressed = PTH-mediated: primary (commonest; low-normal phosphate), tertiary (CKD), FHH, lithium → specialist interpretation first.
- FHH — lifelong, family history, low calcium excretion; one low ratio is a clue, not a verdict → endocrinology.
- PTH suppressed = non-PTH-mediated: malignancy (rising fast, raised ALP), myeloma, vitamin D excess, sarcoidosis, TB, thyrotoxicosis, immobility, milk-alkali → parallel work-up; NG12 on its own criteria.
- Drugs — commonest reversible: high-dose vitamin D, calcium, antacids, thiazides, lithium, teriparatide, vitamin A. Ask about bought supplements.
- Uncertain — say so; investigate in parallel; name the reviewer and date.
5Treat today — mild, asymptomatic, well
- Contributors: review calcium, vitamin D (including bought), calcium antacids, thiazides → stop where appropriate, recheck; persists → unmasked PHPT? Osteoporosis supplements: review, not automatic stop.
- Lithium: never stop unilaterally — prescriber or psychiatry; check the level. Review digoxin.
- Advice: adequate fluids within cardiac and renal limits (no fixed 2–3 L); keep mobile; normal dietary calcium.
- Not here: loop diuretic, IV fluids, bisphosphonate, denosumab, calcitonin, glucocorticoid. Doses: NICE/SPC, BNF, local formulary.
6Refer routinely
- Confirmed PHPT with symptoms, renal stones, fragility fracture or osteoporosis, or adjusted Ca²⁺ ≥2.85 → parathyroid surgeon; consider referral even if none (NG132).
- PHPT not for surgery, possible FHH, lithium-associated (with mental health), any PTH needing interpretation → endocrinology. Granulomatous → respiratory; tertiary → renal.
7Never reassure by — never leave >3.5, or 3.0–3.5 needing same-day assessment, in an inbox overnight
- The patient feeling well — above 3.5 is an emergency regardless.
- A normal total calcium with a low albumin — use the adjusted value.
- "Borderline" with no PTH, or a PTH deferred six months — the missed myeloma.
- A suppressed PTH being monitored rather than investigated in parallel.
- Stopping a supplement or thiazide and assuming that was the whole answer.
- A single low urinary calcium ratio — never conclude "FHH, no surgery".
8Safety-net — say it, then document it
999 “Call 999 for confusion, drowsiness, a fit or collapse, chest pain or an irregular heartbeat, vomiting so you cannot keep fluids down, or back pain with leg weakness.” Same day: “Contact us or 111 today if you feel weaker or more tired, cannot eat or drink for more than a day, have severe bone pain, become very thirsty, or pass much more or much less urine. Take no calcium or vitamin D unless agreed, and attend the tests even if you feel well.”
Remote or OOH: ≥3.0 needs face to face — hydration and cognition cannot be judged by phone. Convert to face to face or emergency if unable to attend, vomiting or not drinking, frail or alone, a relative reports confusion, or the result comes out of hours.
✓Safe to manage in primary care only if — all five, documented
Adjusted 2.61–2.79 on a repeat; no block 0–2 row
Asymptomatic, hydrated, normal renal function
PTH raised or non-suppressed; specialist view
Contributors and lithium reviewed; NG12 panel if ≥60
Monitoring, thresholds, named reviewer; safety-net
Summary of the full Reasoning GP hypercalcaemia algorithm, which holds the detail, examination, cause classifier and evidence. Sources: NICE NG132 and its hypercalcaemia visual summary, NG12 (updated April 2026), NG148, NG203; Society for Endocrinology emergency guidance on acute hypercalcaemia (2016); SPCs; local formulary. Clinical reference — follow local acute-transfer, renal and prescribing policies and check doses: NICE/SPC, BNF.