Electrolyte replacement ladder (K / Mg / Phos)
Level-banded K, Mg and phosphate replacement.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Electrolyte
- Phosphate (mg/dL)
- Serum level
- 1.8
- Route
- IV
Result: Phos 1.8 mg/dL: 0.64 mmol/kg IV at 7.5 mmol/hour per Brown 2006.
The tool opens with these values already filled in. Replace them with your own.
What the result means
- Phos 2.3-3.0 mg/dL
- 0.32 mmol/kg IV per Brown 2006.
- Phos 1.6-2.2 mg/dL
- 0.64 mmol/kg IV per Brown 2006.
- Phos 1.5 mg/dL or below
- 1 mmol/kg IV per Brown 2006.
- K 3.0-3.4
- 40 mEq (institutional convention).
- K 2.5-2.9
- 60 mEq (institutional convention).
- K <2.5
- 80 mEq (institutional convention).
- Mg 1.0-1.7
- 2 g MgSO4 IV over 1 h (institutional convention).
- Mg <1.0
- 4 g MgSO4 IV over 1 h (institutional convention).
What you enter
- Electrolyte
- Serum level
- Route
- Renal impairment (eGFR < 30 or AKI)
How this is calculated
Citation
Brown KA, et al. A new graduated dosing regimen for phosphorus replacement in patients receiving nutrition support. JPEN. 2006;30(3):209-214 (phosphate). Potassium and magnesium ladders are institutional conventions; Hammond DA, et al. Crit Care Nurse. 2019;39(1):e13-e18 on reaching target. Read the sources: Brown 2006 (phosphorus) ↗, Hammond 2019 (potassium) ↗, Potassium Phosphates label ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.