Modified Kramer's versus Kramer's Method for Clinical Assessment of Jaundice in Term and Near-Term Neonates

Abstract

Objectives: To compare the performance of Modified Kramer's and Kramer's methods in terms of agreement with total serum bilirubin (TSB).

Methods: This cross-sectional study was done in Level-III neonatal unit in New Delhi. Visibly jaundiced neonates born at ≥35 wk of gestation were enrolled and examined by (i) conventional Kramer's, (ii) Modified Kramer's in artificial (MK-A) and (iii) natural daylight (MK-N), and finally sampled for estimation of TSB by point-of-care spectrophotometry. The primary outcomes were agreement of Kramer's and Modified Kramer's with TSB and accuracy in terms of proportion of bilirubin estimates lying within ±2 mg/dL of TSB; secondary outcome was agreement of MK-A and MK-N with TSB.

Results: A total of 144 neonates with median gestation of 37 wk and mean birth weight of 2788 g were enrolled. Bland Altman analysis between Kramer's and TSB yielded mean difference of 1.7 mg/dL, 95% limits of agreement (LOA) -3.1 to 6.6 mg/dL. For Modified Kramer's and TSB, mean difference was -0.02 mg/dL, 95% LOA -4.7 to 4.7 mg/dL under artificial light; 0.02 mg/dL, 95% LOA -4.2 to 4.2 mg/dL under natural daylight. MK-N had highest proportion of bilirubin estimates lying within ±2 mg/dL of TSB (68.7%) as compared to MK-A (59.7%) [OR, 1.77; 95% CI, 1.09 to 2.86] and Kramer's (45.8%) [OR, 1.65; 95% CI, 1.27 to 2.15].

Conclusions: Though all the three methods had poor agreement with TSB, Modified Kramer's method when performed in natural light had reasonable accuracy, however limited clinical utility, in evaluation of clinical jaundice.

Keywords: Clinical icterus; Kramer’s method; Neonatal hyperbilirubinemia; Neonatal jaundice; Visual assessment.