Characterization of creatinine error in ketotic patients. A prospective comparison of alkaline picrate methods with an enzymatic method

Am J Clin Pathol. 1985 Nov;84(5):659-64. doi: 10.1093/ajcp/84.5.659.

Abstract

Creatinine measurement by alkaline picrate reagents is subject to positive interference by acetoacetate. Enzymatic reagents avoid this interference and have been adapted to instruments such as the Ektachem-400 (Kodak). By documenting the discrepancy between alkaline picrate and Ektachem determinations for creatinine, the authors prospectively identified ketotic patients in whom the presence of ketones was responsible for a significant creatinine error. During their three-month survey, they identified 50 such ketotic inpatients. Those admitted to the medicine service represented almost 5% of all medicine admissions over this time. Of the total specimens, the mean discrepancy was 14 +/- 8 mg/L with a range of 4-44 mg/L. The greater the ketosis, the greater the discrepancy. Two-thirds of the samples were normal on the Ektachem but greater than normal by picrate methods. In addition to diabetes or ethanol abuse, 17% of the ketotic patients had severe or terminal illness that was generally associated with malnutrition.

Publication types

  • Comparative Study

MeSH terms

  • Acetoacetates / blood
  • Acidosis / blood*
  • Adolescent
  • Adult
  • Aged
  • Child
  • Child, Preschool
  • Creatinine / blood*
  • Female
  • Humans
  • Ketosis / blood*
  • Male
  • Methods
  • Middle Aged
  • Picrates
  • Prospective Studies
  • Time Factors

Substances

  • Acetoacetates
  • Picrates
  • acetoacetic acid
  • Creatinine