The Kodak Ektachem clinical chemistry slide for measurement of bilirubin in newborns: principles and performance.

Abstract

In this slide, unconjugated bilirubin and its sugar conjugates interact with a cationic polymeric mordant to form spectrally enhanced complexes having similar absorptivities at approximately 400 nm. With reflection densitometry and appropriate mathematical transformation, readings at this wavelength are linearly related to bilirubin concentrations up to 260 mg/L. The slide requires 10 microL of serum, is precise (total CV less than 2% determined over 20 days for the analyte range 39-184 mg/L), gives results that correlate well with the Doumas et al. modification of the Jendrassik-Gróf method (slope 0.95, intercept 0.3, Sy . x 3.4, r = 0.991), and is relatively interference free. Also, the slide measures less loss of bilirubin after in vitro illumination of serum specimens than do diazo tests. An intermediate layer in the slide minimizes the spectral interference from hemoglobin and prevents the detection of the strongly protein-linked ("delta") bilirubin found in many jaundiced adults. The method is recommended for newborns (less than or equal to 14 days), in whom the incidence of delta bilirubin is negligible.

Estimation of bilirubin using BiliChek™, a transcutaneous bilirubin measurement device: Effects of gestational age and use of phototherapy

“…Using reflection densitometry and appropriate mathematical transformation, readings are linearly related to bilirubin concentration. Results obtained by this method correlate well with previous modifications of the Jendrassik-Grof method (19).…”

Efficacy of Subthreshold Newborn Phototherapy During the Birth Hospitalization in Preventing Readmission for Phototherapy

“…During the time of this study, all TSB levels were measured using the Vitros BuBc Neonatal Bilirubin method (Ortho Clinical Diagnostics). As previously reported, Ortho Clinical Diagnostics issued new calibrators for their bilirubin testing instruments in May 2012, which resulted in a significant decrease in measured TSB levels and the use of phototherapy.…”

Comparison of the transcutaneous bilirubinometers BiliCheck and Minolta JM‐103 in preterm neonates

“…TsB was determined by reflection densitometry on Vitros 5.1 (Ortho-Clinical Diagnostic, Rochester, NY, USA). TsB was calculated as the sum of measured unconjugated (Bu) and conjugated bilirubin (Bc) (Vitros BuBc slide) (12). Bu and Bc react with a mordant, and reflection densities at wavelengths of 400 and 460 nm were measured.…”