Objective: To evaluate the suitability of urine samples collected with cotton balls placed into diapers for routine laboratory chemistry analyses. Study design: Twenty pools of residual unpreserved urine samples were separated into control and treated aliquots. The treated samples were absorbed into 2 different brands of cotton balls, wrapped in 3 different brands of diapers, and incubated at 37°C for 1 hour. The urine-soaked cotton balls were placed into a syringe and expressed via plunger depression. Urine sodium, potassium, creatinine, urea, calcium, magnesium, inorganic phosphorus, albumin, and total protein were measured on all samples on 5 automated clinical chemistry platforms: Ortho Vitros 4600, Siemens Dimension Vista 500, Beckman Coulter AU5822, Roche Cobas 6000, and Abbott Architect c8000 at 5 separate hospital laboratories. Criteria used to exclude the presence of significant effects of urine from presoaked cotton balls in a diaper on the measurement of chemistry laboratory tests were R2 >0.95, slope of 0.9-1.1, and mean bias within ±10%. Results: Albumin and total protein measurements demonstrated significant negative bias in urine from both brands of presoaked cotton balls with all brands of diapers on all 5 chemistry platforms compared with the control urine. We did not observe a significant effect of presoaking urine in cotton balls in a diaper on the measurement of sodium, inorganic phosphorus, and urea. The remaining tests demonstrated significant effects when measured in urine from presoaked cotton balls and/or diapers that were specific to the chemistry analyzer platform or diaper. Conclusions: Diaper and cotton ball-based urine collection significantly impacts the measurement of several common chemistry assays.
Bibliographical noteFunding Information:
Brandon Cavinee from Nationwide Children's Hospital Core Laboratory, Bereket Getachew from the M Health Fairview West Bank Acute Care Laboratory, Chimah Amukele from Lurie Children’s Hospital, Krinaben Patel from The Ohio State University Wexner Medical Center, Alyson Nelson, Mikayla Pasewald, and Kevin Grant from UW Health core laboratory are gratefully acknowledged.
© 2022 Elsevier Inc.
- cotton ball
- laboratory testing
- urine collection
PubMed: MeSH publication types
- Journal Article