KDIGO PTH Target Ranges by GFR Stage
KDIGO does not provide specific PTH target ranges that vary by GFR stage for CKD G3a-G5 (non-dialysis patients); instead, the guideline recommends monitoring PTH trends and treating only when levels are progressively rising or persistently elevated, without defining precise numerical targets for these stages. 1
PTH Targets for Dialysis Patients (CKD G5D)
For patients on dialysis (CKD stage G5D), KDIGO suggests maintaining intact PTH in the range of approximately 2 to 9 times the upper normal limit of the assay. 2, 3
- This represents a significant departure from the previous K/DOQI guideline which specified an absolute range of 150-300 pg/mL 2
- The shift to a multiple of the upper reference limit (URL) accounts for variability between different PTH assays 4, 3
- Marked changes in PTH concentrations in either direction within this range should prompt initiation or change in therapy to avoid progression outside this range 2
Critical Caveat for PTH Measurement
The reference range used matters significantly for classification:
- Different PTH assays can classify 12-18% of dialysis patients differently when using manufacturer-provided reference ranges 4
- Using vitamin D-replete populations (25-OH vitamin D >75 nmol/L) to establish reference ranges significantly improves consistency between assays 3
- If intact PTH levels fall below 2 times the upper limit of normal, calcitriol, vitamin D analogs, and/or calcimimetics should be reduced or stopped 1
PTH Monitoring for Non-Dialysis CKD (G3a-G5)
KDIGO recommends monitoring PTH levels but does not establish specific target ranges for CKD stages G3a through G5 not on dialysis. 1
The guideline suggests reasonable monitoring intervals based on CKD stage:
- CKD G3a-G3b: Measure PTH based on baseline level and CKD progression (no fixed interval specified) 1
- CKD G4: Monitor PTH every 6-12 months 1
- CKD G5 (not on dialysis): Monitor PTH every 3-6 months 1
Treatment Approach for Non-Dialysis CKD
Rather than treating to specific PTH targets, treatment decisions should be based on trends showing progressive rises or persistently elevated PTH levels, taking into account calcium, phosphate, alkaline phosphatase, and 25(OH)D levels 1
- The 2017 KDIGO update deliberately moved away from rigid PTH targets for non-dialysis CKD patients 1
- Treatment choices should account for the magnitude and reversibility of biochemical abnormalities and CKD progression 1
Post-Kidney Transplant Patients
For transplant recipients, monitoring frequency varies by GFR:
- CKD G1T-G3bT: PTH measured once, with subsequent intervals depending on baseline level and CKD progression 1
- CKD G4T: PTH every 6-12 months 1
- CKD G5T: PTH every 3-6 months 1
Management of PTH abnormalities in transplant patients should follow the same approach as for non-transplant CKD patients at equivalent GFR stages 1