Table 1

Accuracy and precision of analyte recovery from urine introduced into neonate nappies without impermeable membrane and with impermeable membrane

Without impermeable membraneWith impermeable membrane
Absolute changeRelative changeAbsolute changeRelative change
Accuracy (mean)Precision (CV %)Accuracy (mean %)Accuracy (mean)Precision (CV %)Accuracy (mean %)
Sodiummmol/Lmmol/L
 0 minNA0.25%NANA0.30%NA
 1 min1.4201.51%7.43%1.9000.67%3.57%
 30 min4.58013.74%21.76%2.2200.75%3.92%
 60 min***2.3000.77%4.04%
 120 min3.880*22.03%2.7400.90%5.03%
Potassiummmol/Lmmol/L
 0 minNA0.49%NANA0.14%NA
 1 min−0.2561.39%−1.82%−0.1000.39%−0.84%
 30 min0.6595.16%3.59%−0.0280.30%−0.81%
 60 min***−0.0280.56%−0.41%
 120 min1.066*7.01%−0.0600.41%−0.37%
Chloridemmol/Lmmol/L
 0 minNA0.65%NANA0.24%NA
 1 min0.3400.82%1.36%0.0600.55%0.20%
 30 min3.0677.62%11.60%0.3200.45%0.70%
 60 min***0.5800.87%1.27%
 120 min2.700*12.84%0.4400.63%1.10%
Gentamicinμg/mLμg/mL
 0 minNA1.66%NANA1.13%NA
 1 min−5.33617.64%−53.15%−0.1461.56%−1.80%
 30 min−8.26541.36%−81.36%−0.8101.63%−8.49%
 60 min***−0.8643.40%−9.75%
 120 min−8.192*−82.22%−0.9101.49%−9.05%
Creatinineμmol/Lμmol/L
 0 minNA2.14%NANA1.27%NA
 1 min−0.2003.52%−1.03%−0.0200.91%0.01%
 30 min0.2075.52%5.92%−0.0200.72%−0.46%
 60 min***0.0401.33%−0.26%
 120 min0.140*3.85%−0.1201.63%−0.37%
  • *Refers to lack of data due to sample desiccation.

  • CV, coefficient of variation; NA, not available.