[Serum bilirubin determination in newborn infants. A new micromethod for the determination of serum of plasma bilirubin in newborn infants].
A micro-method for determination of bilirubin concentration (c) of plasma or serum from newborns was developed. Photometer-readings of the extinction (E) of diluted serum (S) at the bilirubin absorption-band were done against diluted serum as blank, made free from bilirubin by the oxydative power of Chloramin T. Reagents: 1/15 M Na2(HPO4)/K(H2PO4) buffer pH 7,4 (B) and 2 g/dl Chloramin T in B(C). Blank: 0,6 ml C + 0,02 ml S; sample: 0,6 ml B + 0,02 ml S. Reaction time: 4--8 min; filter Hg 436 nm; 1 cm light-path. c (mg/dl) = E X 43,5. Accuracy was determined by a calibration curve (x: mg/dl c of diazo-method; ): E of micro-method); b = 1,008. Reproducibility in series at 14,2 mg/dl resp. 47,9 mg/dl was 1,5% resp. 1,6%. Linearity between E and c is good up to 48 mg/dl c. Specifity was only reduced by serum hemoglobin (h). Sodium heparinate (50 E./ml S) and carotin (952 microgramm/1) had no effect upon E; plasma anticoagulated with heparinate therefore can be used instead of serum. Concentration of h is without importance for clinical purposes; 100 mg/dl h causes about 0,2 mg/dl wrong depression of c.
D001663:Bilirubin / Q000097:blood*; D006801:Humans; D007202:Indicators and Reagents; D007231:Infant, Newborn; D008722:Methods; D010949:Plasma / Q000032:analysis
D007202:Indicators and Reagents; D001663:Bilirubin
Serumbilirubin-Bestimmung beim Neugeborenen. Eine neue Mikromethode für die Bestimmung des Serum-bzw. Plasmabilirubins beim Neugeborenen