MTLAWS Drug Testing Screening Laboratory Practice Test

Creatinine normalization is used to account for urine dilution in urine drug testing. Since urine concentration can vary with hydration, a person with very dilute urine may show lower drug concentrations even if they took the same amount of drug, while concentrated urine can exaggerate levels. Creatinine is produced at a relatively steady rate and excreted in urine, so adjusting drug levels to creatinine (for example, drug concentration per creatinine amount) helps make results more comparable across samples with different dilution. This method is widely used because it reduces the impact of hydration on measured drug levels, though creatinine excretion can still vary with factors like muscle mass, age, sex, diet, and kidney function. Other aspects like urine pH affect drug stability, instrument calibration relates to mass accuracy, and pharmacokinetics deals with how drug levels change over time, which are not addressed by creatinine normalization.