CKD-MBD Biochemical Monitoring Frequency by CKD Stage

CKD Managementmedium

A 55-year-old man with CKD G4 (eGFR 22 mL/min/1.73m²) and no prior biochemical abnormalities of CKD-MBD is seen in nephrology clinic. According to KDIGO 2017 CKD-MBD guidelines, what is the recommended monitoring frequency for serum calcium and phosphate, and for PTH?

  1. A.Calcium and phosphate every 1–3 months; PTH every 3–6 months
  2. B.Calcium and phosphate every 3–6 months; PTH every 6–12 monthsCorrect
  3. C.Calcium and phosphate every 6–12 months; PTH based on baseline level and progression
  4. D.Calcium and phosphate monthly; PTH monthly regardless of CKD stage

Explanation

KDIGO 2017 Rec 3.1.1 recommends monitoring serum calcium, phosphate, PTH, and alkaline phosphatase starting in CKD G3a. Rec 3.1.2 specifies intervals by stage: CKD G3a–G3b: calcium and phosphate every 6–12 months, PTH based on baseline level and CKD progression; CKD G4: calcium and phosphate every 3–6 months, PTH every 6–12 months; CKD G5 including G5D: calcium and phosphate every 1–3 months, PTH every 3–6 months; CKD G4–G5D: alkaline phosphatase activity every 12 months (or more frequently in the presence of elevated PTH). Monitoring frequency should increase in patients receiving CKD-MBD treatments or with identified biochemical abnormalities.

Why each option

A.
Incorrect. The 1–3 month interval for calcium/phosphate and 3–6 month interval for PTH applies to CKD G5/G5D, not G4.
B.
Correct. CKD G4: calcium and phosphate every 3–6 months; PTH every 6–12 months per KDIGO 2017 Rec 3.1.2.
C.
Incorrect. The 6–12 month interval for calcium/phosphate and PTH-based-on-baseline approach applies to CKD G3a–G3b, not G4.
D.
Incorrect. Monthly monitoring is not the KDIGO recommendation for CKD G4; it would represent over-testing beyond guideline specifications.

Reference: KDIGO 2017 CKD-MBD Guideline Update. Kidney Int Suppl. 2017;7:1–59. Rec 3.1.1–3.1.2.

This is one of 1,100 questions in the MedBoardSA nephrology bank, with timed test mode, tutor mode, and progress tracking by topic.

Practise the full bank

More CKD Management questions

Browse other topics