title: Implications of storing urinary DNA from different populations for molecular analyses.
abstract: BACKGROUND
  Molecular diagnosis using urine is established for many sexually transmitted diseases and is increasingly used to diagnose tumours and other infectious diseases. Storage of urine prior to analysis, whether due to home collection or bio-banking, is increasingly advocated yet no best practice has emerged. Here, we examined the stability of DNA in stored urine in two populations over 28 days.
  
  
  METHODS
  Urine from 40 (20 male) healthy volunteers from two populations, Italy and Zambia, was stored at four different temperatures (RT, 4 degrees C, -20 degrees C & -80 degrees C) with and without EDTA preservative solution. Urines were extracted at days 0, 1, 3, 7 and 28 after storage. Human DNA content was measured using multi-copy (ALU J) and single copy (TLR2) targets by quantitative real-time PCR. Zambian and Italian samples contained comparable DNA quantity at time zero. Generally, two trends were observed during storage; no degradation, or rapid degradation from days 0 to 7 followed by little further degradation to 28 days. The biphasic degradation was always observed in Zambia regardless of storage conditions, but only twice in Italy.
  
  
  CONCLUSIONS
  Site-specific differences in urine composition significantly affect the stability of DNA during storage. Assessing the quality of stored urine for molecular analysis, by using the type of strategy described here, is paramount before these samples are used for molecular prognostic monitoring, genetic analyses and disease diagnosis.
authors.affiliation: National Institute for Infectious Diseases L. Spallanzani, IRCCS, Roma, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Cannas
authors.forename: Glendah
authors.initials: G
authors.lastname: Kalunga
authors.forename: Clare
authors.initials: C
authors.lastname: Green
authors.forename: Ludovica
authors.initials: L
authors.lastname: Calvo
authors.forename: Patrick
authors.initials: P
authors.lastname: Katemangwe
authors.forename: Klaus
authors.initials: K
authors.lastname: Reither
authors.forename: Mark D
authors.initials: MD
authors.lastname: Perkins
authors.forename: Leonard
authors.initials: L
authors.lastname: Maboko
authors.forename: Michael
authors.initials: M
authors.lastname: Hoelscher
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Talbot
authors.forename: Peter
authors.initials: P
authors.lastname: Mwaba
authors.forename: Alimuddin I
authors.initials: AI
authors.lastname: Zumla
authors.forename: Enrico
authors.initials: E
authors.lastname: Girardi
authors.forename: Jim F
authors.initials: JF
authors.lastname: Huggett
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D019411:Clinical Laboratory Techniques; D004247:DNA / Q000032:analysis / Q000652:urine*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D013048:Specimen Handling; D013696:Temperature; D013997:Time Factors
chemical_list: D004247:DNA