A Detailed Comparison of Morning and Random Urine Specimen Levels with 24 Hour Urinary Excretion Levels of Seven Biochemical Parameters with a Proposed Formula

Ann Clin Lab Sci. 2017 Mar;47(2):201-207.


This study aimed to evaluate the validity of the suggested method (SM) to estimate the urinary level of seven biochemical parameters within 24 hours with an innovative formula using morning and random urine specimens. A total of 133 clients referring to the laboratory of the Endocrinology & Metabolism Research Institute, Tehran University of Medical Sciences, participated voluntarily in the investigation with providing three urine samples of 24-hour, morning and random. Seven biochemical parameters (calcium, phosphorus, urea, creatinine, uric acid, microalbumin and protein) were measured in all three samples. After applying the proposed formula and the formula of the parameter-to-creatinine ratio (p/c), the results obtained from morning and random samples were compared statistically with those of 24-hour urine samples. Compared to the p/c ratio method, nearly all the results of the SM were more correlated with the 24-hour method (24-hrM). Among the results obtained in the SM, the values of urea, calcium and phosphorus in the morning urine and those of uric acid, microalbumin, protein and creatinine in the random urine showed higher correlation with the respective results of the 24-hrM. The new method seems to be a feasible alternative to the methods of 24-hour and p/c ratio for measuring morning values of urea, calcium and phosphorus as well as random values of uric acid, microalbumin, protein and creatinine. This method is a compromised method when 24 hours urine specimen is impossible to get by certain patients.

Keywords: 24-hour urine sample; Microalbumin to creatinine ratio; Protein to creatinine ratio; proteinuria; spot urine sample; urinary excretion rate.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Albuminuria / urine
  • Calcium / urine
  • Creatinine / urine
  • Female
  • Humans
  • Male
  • Middle Aged
  • Proteinuria / urine
  • ROC Curve
  • Time Factors
  • Urinalysis / methods*
  • Young Adult


  • Creatinine
  • Calcium