From the Research
The normal creatinine reference range in mmol/L is typically 0.06-0.12 mmol/L for adult males and 0.05-0.09 mmol/L for adult females, as supported by the most recent study 1. These values may vary slightly between different laboratories and testing methods. Creatinine is a waste product produced by muscle metabolism and is filtered by the kidneys, making it a useful marker for kidney function. Higher levels indicate potential kidney dysfunction as they suggest the kidneys aren't effectively clearing creatinine from the blood. Factors affecting creatinine levels include muscle mass (more muscle typically means higher baseline creatinine), age, gender, diet (particularly meat consumption), and certain medications. When interpreting creatinine results, it's essential to consider these factors along with other kidney function tests like blood urea nitrogen (BUN), estimated glomerular filtration rate (eGFR), and urinalysis for a comprehensive assessment of kidney health, as discussed in 2 and 3. It's also crucial to be aware of interlaboratory differences in measurement techniques and reference intervals, as highlighted in 1, which can impact clinical decision-making. The study 1 emphasizes the importance of using age-specific reference intervals and being cautious when interpreting serum creatinine and symmetric dimethylarginine values due to potential interlaboratory variability. In contrast, older studies like 4 and 5 focused on different aspects of creatinine reporting and reference intervals, but their findings are not as directly relevant to the current question as the more recent study 1.