Reasoning GP · Algorithm · 1-page summary
Abnormal bone profile in adults
For: adults with an abnormal calcium, phosphate, ALP or PTH in primary care. Not for: children (ALP is physiologically high in growth; rickets) — paediatric advice; pregnancy (placental ALP) — specialist advice; detailed management → hypercalcaemia, hypocalcaemia and abnormal LFT algorithms.
Core rule: never read one value alone — read the lab's adjusted calcium, phosphate and ALP together, pair PTH with a concurrent calcium and ALP with GGT. A "normal" PTH with a high calcium is inappropriate (PHPT or FHH); a suppressed PTH means look for malignancy.
0Stop — emergency hospital assessment — 999 if clinically unstable
- Adjusted Ca >3.5 mmol/L however well, or ≥3.0 with significant symptoms; confusion, reduced consciousness, persistent vomiting, dehydration, AKI, arrhythmia or ECG change → Same-day hospital; unstable → 999
- Adjusted Ca <1.90 mmol/L, or tetany, seizure, laryngospasm, paraesthesia with QT prolongation or arrhythmia → emergency hospital (IV calcium gluconate with ECG monitoring) 999
- Back pain with neurological symptoms or signs and possible bone metastases (suspected cord compression) → acute oncology/MSCC team Immediately; whole-spine MRI within 24 hours
- While waiting: ABCDE; ECG if immediately available; stop calcium and vitamin D preparations; urgent hospital advice. Do not delay transfer to repeat bloods. IV saline, IV bisphosphonate and IV calcium are hospital treatments; correct magnesium.
1Triage the result — adjusted Ca in mmol/L
| Result | Action |
|---|---|
| 3.0–3.5, no symptoms | Same-day face to face or specialist discussion. |
| ≥2.6 (≥2.5 if PHPT features) | Repeat; PTH with concurrent Ca once raised twice. |
| Any abnormal Ca | Phosphate, Mg, 25-OH-D, eGFR; PTH if low. |
| Isolated raised ALP | Repeat; GGT + LFTs: raised → liver; normal → bone. |
2Screen — serious causes
- Persistent ↑Ca + suppressed PTH → parallel malignancy work-up, specialist advice Urgent; unwell → Same-day
- ≥60, persistent bone/back pain or unexplained fracture → FBC, Ca, ESR/PV, electrophoresis + free light chains; myeloma → suspected cancer pathway (NG12).
- ↑ALP + bone pain + pathological fracture + weight loss → Urgent suspected cancer pathway for the likely primary.
- Known Paget's: acute or progressive severe pain → Urgent specialist + imaging; new neurology → Same-day, urgent MRI.
3Assess
☐ Bones, stones, groans, moans; tingling, cramps; bone pain, proximal weakness, weight loss ☐ Thiazides, lithium, calcium, antacids, vitamin D or A, biotin ☐ Chvostek/Trousseau, BP, rise from chair, deformity, nodes ☐ Suppressed PTH: FBC, LFTs, inflammatory markers ± CXR ☐ X-ray symptomatic bones
Not in primary care: ionised Ca, PTHrP, 1,25-(OH)₂D, ACE screen, parathyroid imaging.
4Classify — the pattern names the cause
- ↑Ca, PTH raised or unsuppressed → primary hyperPTH; urine calcium (FHH?), eGFR, DXA, renal ultrasound.
- ↑Ca, suppressed PTH → malignancy, myeloma, sarcoid, vitamin D toxicity → block 2.
- ↓Ca, ↑PTH → vitamin D deficiency, CKD, malabsorption. Low/normal PTH → hypoparathyroidism, low Mg.
- ↑ALP, normal GGT → fracture, Paget's (normal Ca/PO₄), osteomalacia (↓Ca ↓PO₄), metastases.
- FHH — low urine calcium supports, never proves → endocrinology before any surgery.
- Uncertain (e.g. raised PTH, normal Ca) → repeat, exclude secondary causes, discuss with endocrinology.
5Treat today
- Vitamin D deficiency (<25 nmol/L) needing rapid correction: e.g. colecalciferol 50,000 IU weekly × 6 → 800–2,000 IU/day; 25-OH-D recheck only if symptomatic, malabsorption or poor adherence.
- High Ca: stop calcium/vitamin D supplements; avoid thiazides and dehydration; PHPT: do not restrict dietary calcium.
- Specialist-led: cinacalcet, alfacalcidol, Paget's zoledronic acid, CKD binders. Doses: NICE/SPC, BNF, local formulary.
6Refer routinely
- Confirmed PHPT with symptoms, renal stones, fragility fracture or osteoporosis, or Ca ≥2.85 → parathyroid surgeon; consider even if none (NG132).
- PHPT surveillance only as agreed with endocrinology: Ca + eGFR at least yearly, DXA every 2–3 years.
- Endocrine: hypoparathyroidism, FHH. Metabolic bone: Paget's, osteomalacia, persistent bone ALP with pain. Renal: rising PTH in CKD.
7Never reassure by
- A "normal" PTH with a high calcium — it is inappropriate.
- An isolated raised ALP called "liver" without a GGT.
- A suppressed PTH monitored rather than investigated in parallel.
- Repeating bloods while an unwell patient waits for transfer.
- One low urine calcium ratio ("FHH") or one raised PTH ("normocalcaemic PHPT").
- Stopping or delaying denosumab without an alternative plan.
8Safety-net — say it, then document it
999 “Call 999 for confusion or drowsiness, a fit or collapse, chest pain or an irregular heartbeat, a tight throat or noisy breathing with tingling or cramps, or back pain with new leg weakness, numbness or loss of bladder or bowel control.” Same day “Contact us or 111 today for vomiting or not keeping fluids down, severe thirst or passing much more urine, new tingling around the mouth or fingers or cramps, or new bone pain or a fracture.”
Remote or OOH: adjusted Ca ≥3.0 mmol/L or any symptom above → same-day face-to-face; <1.90 is an emergency. On bisphosphonate or denosumab: report thigh, groin or hip pain and jaw symptoms.
✓Safe to manage in primary care only if — all five, documented
No block 0–2 trigger; result repeated
Ca, PO₄, ALP read together; PTH paired with Ca
Raised ALP: GGT done; bone cause named
Drugs and supplements reviewed; NG12 tests if ≥60
Recheck date, referral route; safety-net given
Summary of the full Reasoning GP abnormal bone profile algorithm, which holds the detail, examination, treatment and evidence. Sources: NICE NG132, NG12 (updated April 2026), NG234; Society for Endocrinology emergency guidance on acute hypercalcaemia (2016); NOGG 2024; KDIGO CKD-MBD 2017; MHRA; SPCs; local formulary. Clinical reference — follow local acute-transfer and prescribing policies and check doses: NICE/SPC, BNF.