Rayon balls and disposable-diaper material selectively adsorb creatinine

Area of Science:

• Clinical Chemistry
• Biochemical Analysis
• Pediatric Medicine

Background:

• Urine sample collection in infants often uses absorbent materials in diapers.
• Creatinine concentration is a key biomarker used to normalize urine excretion measurements.
• The accuracy of creatinine normalization depends on the integrity of the urine sample post-collection.

Purpose of the Study:

• To investigate the impact of absorbent materials on urinary creatinine concentration.
• To determine if urine absorption by cotton, rayon, or diaper material introduces artifacts.
• To assess the reliability of using creatinine concentration from absorbed infant urine samples.

Main Methods:

• Urine samples from adults and infants were tested.
• Creatinine concentration was measured before and after absorption by cotton balls, rayon balls, and diaper material.
• Experiments were conducted across a range of sample wetness.

Main Results:

• Rayon balls and diaper material significantly decreased creatinine concentration in urine samples.
• This artifactual decrease was more pronounced in lightly wetted samples.
• Cotton balls showed a smaller, less significant decrease in creatinine concentration (3% vs. 9-13% for rayon/diaper material).

Conclusions:

• Rayon balls and diaper material selectively adsorb creatinine from human urine.
• These materials can introduce significant artifacts into infant urine sample analysis.
• The use of rayon balls and diaper material for urine collection may compromise the accuracy of creatinine-based measurements.