title: Prevalence of isolated non-albumin proteinuria in the US population tested for both, urine total protein and urine albumin: An unexpected discovery.
abstract: BACKGROUND
  Isolated non-albumin proteinuria (NAP) is a condition when urine total protein concentrations are elevated without elevation of urine albumin. The prevalence of NAP in the US population tested for both, urine total protein and albumin was assessed in this study.
  
  
  METHODS
  The database of a US nationwide laboratory network was queried for test results when random urine albumin was ordered together with urine total protein and also when timed 24-hour urine albumin was ordered together with urine total protein. The total prevalence of NAP in the US population tested for both, urine total protein and albumin was calculated for patient groups having normal and low-normal urine albumin (random and timed) with elevated and severely increased urine total protein (random and timed). Also, the prevalence of NAP was calculated for patients with normal urine albumin to assess the probability of missing proteinuria if only urine albumin is measured.
  
  
  RESULTS
  The prevalence of NAP in the random samples group was 10.1% (15.2% for females and 4.7% for males). Among patients with normal random albumin, there were 20.0% (27.3% of females and 10.7% of males) patients with NAP. The prevalence of NAP in the timed samples group was 24.6% (29.8% for females and 18.5% for males). Among patients with normal timed urine albumin, there were 36.2% (40.0% of females and 30.8% of males) patients with NAP. There was a strong positive association with female gender and NAP in most patients groups.
  
  
  CONCLUSIONS
  Testing for only urine (micro)albumin can miss up to 40% of females and 30.8% of males with gross proteinuria.
authors.affiliation: Laboratory Corporation of America® Holdings, 112 Orange Drive, Elon, NC 27244, USA. Electronic address: katayea@labcorp.com.
authors.forename: Alexander
authors.initials: A
authors.lastname: Katayev
authors.affiliation: Laboratory Corporation of America® Holdings, 550 17-th Ave., Seattle, WA 98122, USA. Electronic address: zebelma@labcorp.com.
authors.forename: Arthur M
authors.initials: AM
authors.lastname: Zebelman
authors.affiliation: Laboratory Corporation of America® Holdings, 112 Orange Drive, Elon, NC 27244, USA. Electronic address: sharpm@labcorp.com.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Sharp
authors.affiliation: New York Diabetes Center, 1160 Greacen Point Rd., Mamaroneck, NY 10543, USA. Electronic address: samflynn@diabetesscientist.com.
authors.lastname: Samantha Flynn
authors.affiliation: New York Diabetes Center, 1160 Greacen Point Rd., Mamaroneck, NY 10543, USA. Electronic address: md@diabetesscientist.com.
authors.forename: Richard K
authors.initials: RK
authors.lastname: Bernstein
mesh_terms: D000418:Albumins / Q000032:analysis*; D003404:Creatinine / Q000652:urine; D005260:Female; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D015995:Prevalence; D011507:Proteinuria / Q000453:epidemiology* / Q000652:urine; D014481:United States / Q000453:epidemiology; D016482:Urinalysis / Q000379:methods* / Q000592:standards*
chemical_list: D000418:Albumins; D003404:Creatinine
keywords: Albumin excretion rate; Albumin-to-creatinine ratio; Albuminuria; Non-albumin proteinuria; Protein excretion rate; Protein-to-creatinine ratio; Proteinuria