An investigation of normal urine with a creatinine concentration under the cutoff of 20 mg/dL for specimen validity testing in a toxicology laboratory

J Forensic Sci. 2014 May;59(3):806-10. doi: 10.1111/1556-4029.12386. Epub 2014 Feb 6.


In clinical and forensic toxicology laboratories, one commonly used method for urine specimen validity testing is creatinine concentration. In this study, workplace guidelines are examined to determine their relevance to forensic and clinical toxicology samples. Specifically, it investigates the occurrence of urine creatinine concentrations under 20 mg/dL and notes potential issues with factors influencing creatinine concentration by utilizing a simple, novel method consisting of cation-paring high-pressure liquid chromatography in tandem with ultraviolet detection to determine the creatinine concentration in 3019 donors. Of the 4227 sample population in this study, 209 (4.94%) were below the cutoff value of 20 mg/dL for dilute urine. Because there are many factors that can influence the urinary creatinine concentration, samples that have creatinine under the 20 mg/dL cutoff do not always implicate sample adulteration.

Keywords: adulteration; creatinine; forensic science; toxicology; urine specimen validity; workplace guidelines.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatography, High Pressure Liquid
  • Creatinine / urine*
  • False Negative Reactions
  • Female
  • Humans
  • Laboratories
  • Male
  • Reference Values
  • Substance Abuse Detection / methods*
  • Substance-Related Disorders / urine


  • Creatinine