From the Guidelines
A low creatinine level of 0.48 mg/dL is indicative of potential protein-energy malnutrition and wasting of skeletal muscle, and individuals with such levels should be evaluated for these conditions, as suggested by the National Kidney Foundation's clinical practice guidelines 1. This value is below the normal range, which can vary by gender and other factors, but a level of 0.48 mg/dL is generally considered low. According to the guidelines, individuals with low predialysis or stabilized serum creatinine (less than approximately 10 mg/dL) should be evaluated for protein-energy malnutrition and wasting of skeletal muscle 1. Some key points to consider in the context of low creatinine levels include:
- Low dietary protein intake (DPI) and/or diminished skeletal muscle mass are associated with increased mortality rates, as indicated by a low creatinine index and low serum creatinine concentration in the absence of substantial endogenous urinary creatinine clearance 1.
- Muscle mass significantly influences creatinine levels in the blood, as creatinine is produced from creatine in muscle tissue at a fairly constant rate.
- A healthcare provider may want to assess overall nutritional status, muscle health, and possibly conduct additional kidney function tests to evaluate the context of a low creatinine level.
- While high creatinine is often concerning for kidney problems, low creatinine usually doesn't require specific treatment but should be interpreted alongside other clinical findings.
From the Research
Low Creatinine Levels
- A low creatinine level of 0.48 may indicate a decrease in muscle mass, as creatinine is a biochemical marker of muscle mass 2.
- Low serum creatinine levels have been associated with sarcopenia, which can play a significant role in morbidity and mortality in different clinical settings 2.
- However, low creatinine clearance is not a categorical sign of renal disease, as protein intake has a direct and quantitative effect on creatinine clearance in healthy subjects 3.
Factors Affecting Creatinine Levels
- Protein intake can affect creatinine levels, with high protein diets increasing creatinine clearance in healthy adults 4.
- A low protein diet, on the other hand, may be associated with lower hemoglobin and albumin levels, shorter 6-min walking distance, and lower leucine levels in patients with chronic kidney disease 5.
- Age can also affect creatinine levels, with elderly healthy subjects having different correlations between creatinine clearance and urea nitrogen excretion compared to young healthy subjects 3.
Clinical Application of Creatinine
- Serum creatinine is the most widely used functional biomarker of the kidney, but its use is associated with substantial shortcomings 6.
- Understanding the pathways involved in creatinine generation and metabolism, as well as the techniques involved in measuring creatinine concentrations, is critical for accurate interpretation of creatinine values 6.
- Alternative functional biomarkers of the kidney may provide additional information on kidney function, particularly in patients with low creatinine levels 6.