title: Quality of DNA extracted from saliva samples collected with the Oragene™ DNA self-collection kit.
abstract: BACKGROUND
  Large epidemiological studies in DNA biobanks have increasingly used less invasive methods for obtaining DNA samples, such as saliva collection. Although lower amounts of DNA are obtained as compared with blood collection, this method has been widely used because of its more simple logistics and increased response rate. The present study aimed to verify whether a storage time of 8 months decreases the quality of DNA from collected samples.
  
  
  METHODS
  Saliva samples were collected with an OrageneTM DNA Self-Collection Kit from 4,110 subjects aged 14-15 years. The samples were processed in two aliquots with an 8-month interval between them. Quantitative and qualitative evaluations were carried out in 20% of the samples by spectrophotometry and genotyping. Descriptive analyses and paired t-tests were performed.
  
  
  RESULTS
  The mean volume of saliva collected was 2.2 mL per subject, yielding on average 184.8 μg DNA per kit. Most samples showed a Ratio of OD differences (RAT) between 1.6 and 1.8 in the qualitative evaluation. The evaluation of DNA quality by TaqMan®, High Resolution Melting (HRM), and restriction fragment length polymorphism-PCR (RFLP-PCR) showed a rate of success of up to 98% of the samples. The sample store time did not reduce either the quantity or quality of DNA extracted with the Oragene kit.
  
  
  CONCLUSIONS
  The study results showed that a storage period of 8 months at room temperature did not reduce the quality of the DNA obtained. In addition, the use of the Oragene kit during fieldwork in large population-based studies allows for DNA of high quantity and high quality.
authors.affiliation: Morphology Department, Institute of Biology, Universidade Federal de Pelotas, Pelotas, Brazil. anapaula.epi@gmail.com
authors.forename: Ana P
authors.initials: AP
authors.lastname: Nunes
authors.forename: Isabel O
authors.initials: IO
authors.lastname: Oliveira
authors.forename: Betânia R
authors.initials: BR
authors.lastname: Santos
authors.forename: Cristini
authors.initials: C
authors.lastname: Millech
authors.forename: Liziane P
authors.initials: LP
authors.lastname: Silva
authors.forename: David A
authors.initials: DA
authors.lastname: González
authors.forename: Pedro C
authors.initials: PC
authors.lastname: Hallal
authors.forename: Ana M B
authors.initials: AM
authors.lastname: Menezes
authors.forename: Cora L
authors.initials: CL
authors.lastname: Araújo
authors.forename: Fernando C
authors.initials: FC
authors.lastname: Barros
mesh_terms: D000293:Adolescent; D001938:Brazil; D015331:Cohort Studies; D004247:DNA / Q000032:analysis* / Q000302:isolation & purification; D003627:Data Interpretation, Statistical; D005215:Fasting; D005260:Female; D060005:Genotyping Techniques; D006801:Humans; D007201:Indicator Dilution Techniques; D008297:Male; D011786:Quality Control; D011933:Reagent Kits, Diagnostic; D015203:Reproducibility of Results; D012463:Saliva / Q000737:chemistry*; D013048:Specimen Handling / Q000592:standards*; D013053:Spectrophotometry; D013997:Time Factors
chemical_list: D011933:Reagent Kits, Diagnostic; D004247:DNA