Candidate reference method for determination of total bilirubin in serum: development and validation.

Abstract

This candidate Reference Method for measuring total bilirubin in serum is based on the Jendrassik-Gróf principle (Clin Chem 29: 297-301, 1983). Standard Reference Material no. 916 bilirubin (National Bureau of Standards) is used as the standard. Bilirubin standard solutions may be prepared either in human serum or in 40 g/L albumin solution (human or bovine), because we found the molar absorptivity of the azopigment at 598 nm to be identical in these media. The absorptivities of the unconjugated and conjugated azopigments appear to be identical, but the conjugated azopigment is completely hydrolyzed in the final reaction mixture. Bilirubin added to serum from adults or neonates was quantitatively accounted for. Interference by hemoglobin (up to 2 g/L), ascorbic acid (up to 20 mg/L), or zinc (at physiological concentrations) is negligible. Of the therapeutic drugs we tested, only L-dopa and alpha-methyldopa interfere. We established normal adult reference values for total bilirubin and examined the intraindividual variation in 19 subjects.

Effect of infants’ position on serum bilirubin level during conventional phototherapy

“…This measures TSB as the sum of unconjugated bilirubin (Bu) and conjugated bilirubin (Bc), using the Vitros BuBc slide. The test type is endpoint colorometry at wavelengths of 400 and 460 nm, calibrated according to the Jendrassik–Grof method (9).…”

A new transcutaneous bilirubinometer, BiliCheck, used in the neonatal intensive care unit and the maternity ward

“…Here, it is important to document any systematic error or bias (inaccuracy). In comparing BiliCheck with the routine laboratory method (Vitros 950), it was documented (Methods section) that the Vitros 950 has both a low inaccuracy (bias) in relation to the reference method (10,11), and a low imprecision (random analytical variation). The nding that BiliCheck on average underestimated TSB is compatible with another recently published study (16), although direct comparison is dif cult owing to a different method of data presentation.…”

Efectos toxicológicos del uso prolongado e intenso de emisiones de espirales contra mosquitos en ratas y sus implicaciones sobre el control de la malaria

“…The method of Young (1975), was used to determine alkaline phosphatase (ALP). The BCG method of Doumas et al (1985) was used to estimate Albumin. The plasma urea level was measured by commercially available standard blood urea kit (Maizy, France) by Biolabo South Africa.…”