Creatinine of 48.30 μmol/L: Normal Renal Function
A creatinine level of 48.30 μmol/L (approximately 0.55 mg/dL) is well below the normal range and indicates excellent renal function with no clinical concern or intervention required.
Understanding This Value
This creatinine level falls significantly below the normal reference range of 70-115 μmol/L (0.8-1.3 mg/dL) for men and 55-90 μmol/L (0.6-1.0 mg/dL) for women 1
The corresponding estimated GFR would be >90 mL/min/1.73 m², placing this patient in Stage 1 kidney function (normal or increased GFR) according to the internationally recommended CKD staging system 1
Clinical Interpretation
Low creatinine values like this typically reflect reduced muscle mass rather than kidney pathology and are commonly seen in:
- Elderly patients with sarcopenia 1
- Patients with low body weight or reduced muscle mass 1
- Women (who naturally have lower muscle mass than men) 1
- Patients with chronic illness causing muscle wasting 1
Serum creatinine alone should never be used as a standalone marker of renal function because it is affected by body mass, muscle mass, diet, age, and sex 1. However, in this case, the low value indicates no renal impairment whatsoever.
What This Means for Clinical Practice
No renal dose adjustments are needed for any medications at this creatinine level:
- ACE inhibitors and ARBs can be used at standard doses without restriction 1
- Metformin is safe to use (GFR >30 mL/min required) 1
- No diuretic modifications needed 1
- Standard dosing for all renally-cleared medications 2
This patient has no increased cardiovascular or mortality risk from renal dysfunction, as these risks only emerge when eGFR falls below 60 mL/min/1.73 m² (Stage 3 CKD or higher) 1
Common Pitfall to Avoid
Do not confuse low creatinine with renal dysfunction—low values indicate reduced creatinine production (usually from low muscle mass), not impaired kidney clearance 1, 3, 4. The kidney is functioning normally or even supranormally in clearing the reduced amount of creatinine being produced.
If there were any clinical concern about actual kidney function despite this low creatinine, you would need to calculate eGFR using the CKD-EPI equation (which accounts for age, sex, and race) or measure creatinine clearance directly 1. However, with a creatinine this low, such concerns would be unfounded.
No Follow-Up Required
No specific monitoring or intervention is indicated for this creatinine level 1. This represents normal renal function, and the low value simply reflects the patient's body composition rather than any pathological process.