title: Sensitivity and specificity of published strategies using urinary creatinine to identify incomplete 24-h urine collection.
abstract: OBJECTIVE
  Although urinary creatinine has been used to identify incomplete 24-h urine in numerous epidemiologic studies, information on its utility is limited. We examined the sensitivity and specificity of several strategies that use creatinine to identify incomplete urine using the p-aminobenzoic acid (PABA) check method as reference.
  
  
  METHODS
  Subjects were 654 female Japanese dietetic students 18-22 y of age. A single 24-h urine sample was collected, with recording of the time of the start and end of the collection period and missing urine volume. Simultaneous administration of PABA was done to assess completeness. The sensitivity and specificity of five strategies derived from the literature that used creatinine to identify incomplete urine were calculated as the proportion of incomplete and complete urine correctly identified, respectively.
  
  
  RESULTS
  A total of 7.6% of subjects was identified as having incomplete urine by PABA (PABA recovery <85%). This proportion significantly (P < 0.0001) decreased (to 5.5%) after considering self-reported collection time and missing urine volume in the calculation of total urine volume. The sensitivity and specificity of the strategy of Knuimann et al. (incomplete urine = <0.7 of [mmol urinary creatinine x 113]/[21 x kilograms of body weight]) were 0.47 and 0.99, respectively. The corresponding values of other strategies were 0.11-0.22 and 0.57-1.00, respectively.
  
  
  CONCLUSIONS
  At least in well-motivated populations in which the proportion of incomplete urine is presumed to be small, the strategy of Knuimann et al. and consideration of the self-reported collection time and missing urine volume in the estimation of total volume may be useful.
authors.affiliation: Nutritional Epidemiology Program, National Institute of Health and Nutrition, Tokyo, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Murakami
authors.forename: Satoshi
authors.initials: S
authors.lastname: Sasaki
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Uenishi
authors.forename: Tomoko
authors.initials: T
authors.lastname: Watanabe
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Kohri
authors.forename: Mitsuyo
authors.initials: M
authors.lastname: Yamasaki
authors.forename: Reiko
authors.initials: R
authors.lastname: Watanabe
authors.forename: Keiko
authors.initials: K
authors.lastname: Baba
authors.forename: Katsumi
authors.initials: K
authors.lastname: Shibata
authors.forename: Toru
authors.initials: T
authors.lastname: Takahashi
authors.forename: Hitomi
authors.initials: H
authors.lastname: Hayabuchi
authors.forename: Kazuko
authors.initials: K
authors.lastname: Ohki
authors.forename: Junko
authors.initials: J
authors.lastname: Suzuki
mesh_terms: D010129:4-Aminobenzoic Acid / Q000652:urine*; D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000652:urine; D001835:Body Weight / Q000502:physiology; D003404:Creatinine / Q000652:urine*; D016021:Epidemiologic Studies; D005260:Female; D006801:Humans; D007564:Japan; D008657:Metabolic Clearance Rate; D012680:Sensitivity and Specificity; D013997:Time Factors; D016482:Urinalysis / Q000592:standards*; D014803:Vitamin B Complex / Q000652:urine
chemical_list: D015415:Biomarkers; D014803:Vitamin B Complex; D003404:Creatinine; D010129:4-Aminobenzoic Acid