Endo Paget Initial Biochemical Evaluation

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name: endo-paget-initial-biochemical-evaluation
description: Recommends obtaining serum total alkaline phosphatase or a more specific bone formation marker for initial biochemical evaluation after radiological confirmation of Paget’s disease. Triggered after imaging establishes diagnosis to set baseline bone turnover.
---

# Initial biochemical evaluation after radiological diagnosis

## STEP 1 — Gather Information
Confirm Paget’s disease on plain radiographs (or radionuclide bone scan if needed). Assess liver function tests (ALT, AST, bilirubin) to determine if serum total ALP will be interpretable.

## STEP 2 — Rule In / Rule Out
If liver enzymes are normal, serum total ALP is appropriate; if liver disease is present or ALP may be confounded, rule out total ALP and proceed to a specific bone formation/resorption marker.

## STEP 3 — Classify or Stratify
Classify patients into:  
- Normal hepatic function → use serum total ALP.  
- Impaired hepatic function or unreliable ALP → use a specific bone formation marker (e.g., P1NP, BSAP, osteocalcin) or bone resorption marker (e.g., NTx, CTx) as appropriate.

## STEP 4 — Decide
Order the selected biochemical test(s) to establish baseline bone turnover before initiating treatment or monitoring disease activity.

## Clinical Guardrails / Mimics / Pitfalls
Do not rely on total ALP in cholestasis, hepatitis, or infiltrative liver disease without confirming bone‑specific origin; avoid nonspecific markers like hydroxyproline; interpret changes using least significant change (LSC) for the chosen assay; ensure test availability and insurance coverage.

## Concrete Clinical Example
A 70‑year‑old woman has an incidental lytic lesion in the right iliac wing on pelvic X‑ray; a bone scan confirms focal uptake. Liver enzymes are normal. Serum total alkaline phosphatase is ordered to establish baseline bone turnover.

**Source:** Paget’s Disease of Bone: An Endocrine Society Clinical Practice Guideline, Endocrine Society, 2014, DOI:10.1210/jc.2014-2910