Calibration of Direct Reading Photometers for the Determination of Neonatal Bilirubin

Brügmann, G

doi:10.1515/cclm.1990.28.2.83

Cited by 3 publications

(4 citation statements)

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“…15 The calibration of bilirubinometers, however, presents a serious problem. [16][17][18][19] With regard to information that there is no advantage in using new TcB compared with the conventional TcB, the aim of this prospective study was to establish usefulness of conventional TcB in the assessment of NNH during phototherapy or without phototherapy.…”

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confidence: 99%

Improvement of Conventional Transcutaneous Bilirubinometry Results in Term Newborn Infants

Felc

2005

Am J Perinatol

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This prospective study was performed to determine a way to improve conventional transcutaneous bilirubinometry results in healthy term newborn infants. In 118 infants during phototherapy (group A), and in 118 infants without phototherapy (group B), bilirubin determinations were done in duplicate using the Minolta AirShields Jaundice Meter type 101 (transcutaneous bilirubin index [TcB]), and the diazometric method on the Hitachi 717 Automated Analyzer (total reacting serum bilirubin [SeB]). In 112 infants (group C), bilirubin determinations were done in triplicate, using simple direct-reading photometry on the Moltronic Bilirubinometer (direct serum bilirubin [BiB]). A close correlation between TcB and SeB values was observed in group A ( r = 0.69; p < 0.001) and in group B ( r = 0.59; p < 0.001). The 95% confidence intervals of TcB readings corresponding to SeB were +/- 80.7 micromol/L in group A and +/- 76.9 micromol/L in group B, respectively. In group C, using a correctly calibrated BiB with adult sera containing bilirubin concentration in the range 271 to 344 micromol/L, the 95% confidence intervals of parallel TcB and BiB readings corresponding to SeB were +/- 28 micromol/L. Parallel determinations of the TcB and the BiB in healthy term newborn infants give results almost identical to those of bilirubin determination by the laboratory method.

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Improvement of Conventional Transcutaneous Bilirubinometry Results in Term Newborn Infants

Felc

2005

Am J Perinatol

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“…It was therefore suggested (5) that bilirubinometers should be calibrated with a pool of neonatal sera, using the reference method value as the assigned calibrator value. This procedure leads to a marked improvement in accuracy (3,4), but it is impracticable for most laboratories, for the following reasons.…”

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confidence: 99%

“…In the meantime, closer investigation of different control samples has shown that the differences between reference method values and bilirubinometer target values are large for some control sera, but small for others (3,4,7). Thus, some control materials clearly have similar properties to neonatal serum when analysed by direct spectrophotometry.…”

Section: Introductionmentioning

confidence: 99%

Calibrators and Control Samples for Bilirubinometers

Blijenberg¹,

Brügmann²,

Geilenkeuser³

et al. 1993

Clinical Chemistry and Laboratory Medicine

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Summary:The different matrix properties of neonatal serum and commercial control samples can lead to considerable errors in the calibration and control of bilirubinometers. These difficulties can be avoided by calibration with serum from healthy adults which is supplemented with unconjugated bilirubin. But this procedure is impracticable for most routine laboratories.Under certain preconditions, control samples, with bilirubin concentrations determined with correctly calibrated bilirubinometers or spectrophotometers, are also suitable as calibrators. This was established by determination of the bilirubin concentration of 16 different control samples, using both the reference method and correctly calibrated bilirubinometers or spectrophotometers in three or four specialist laboratories. This was also confirmed in several interlaboratory surveys, some involving up to 72 laboratories. The results of these investigations show that a control sample should be used for the calibration of a bilirubinometer only if it meets the following preconditions:1. There should be no significant difference between the bilirubin values determined with the reference method and with a correctly calibrated spectrophotometer or bilirubinometer.2. The bilirubin concentration should lie in the range 230 -300 μηαοΐ/ΐ.The photometric response of bilirubinometers has a limited linear range, so that analytical results greater than 300 μπιοΙ/1 must be rated as basically unreliable.

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“…It was therefore suggested (4) that bilirubinometers should be calibrated with a pool of neonatal sera, and that the assigned value of this pool should be determined with the reference method. This procedure leads to a marked improvement in accuracy (1,2), but it is impracticable for most laboratories. 10 Lab.med.…”

Section: Introductionmentioning

confidence: 99%

Verbesserung der Richtigkeit von Bilirubinometer-Ergebnissen

Schlebusch¹,

Röhle²,

Schneider³

et al. 1991

LaboratoriumsMedizin

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Using two methods, i. e. the reference method of Doumas and measurement with a bilirubinometer, bilirubin was measured in 80 neonatal sera, and in 30 sera from healthy adults containing added, unconjugated bilirubin. In the ränge 150-350 / , the regressions of the analytical values were identical. Thus, correct values for neonatal sera can be obtained by the bilirubinometer affer calibration with a pool of adult sera (containing added bilirubin and standardized with the reference method). However, all bilirubinometers show a more or less curved calibration line, so that deviations from accuracy are to be expected at certain analytytical concentrations, depending on the bilirubin content of the calibrator. A calibrator concentration of 250 / is suggested äs optimal. Using the procedure described here, it is possible to test the linear ränge ofindividual bilirubinometers in the routine laboratory. Keywords: bilirubin -neonates -bilirubinometer -reference method -accuracy Zusammenfassung: Die Bilirubinkonzentration in 80 Neugeborenenseren und 30 Seren von gesunden Erwachsenen, die mit unkonjugiertem Bilirubin aufgestockt waren, wurde mit der Referenzmethode nach Doumas und einem Bilirubinometer gemessen. Die Regressionsfunktionen durch die Meßpunkte sind für beide Gruppen im Bereich 150-350 / identisch. Daraus folgt, daß richtige Ergebnisse in Neugeborenenseren mit Bilirubinometern erzielt werden können, die mit einem Pool von aufgestockten Erwachsenenseren unter Verwendung des Referenzmethodenwertes kalibriert sind. Da alle Bilirubinometer eine mehr oder weniger stark gebogene Kalibrationskurve haben, sind jedoch, abhängig von der Kalibratorkonzentration, Abweichungen von der Richtigkeit in bestimmten Meßbereichen zu erwarten. Als optimale Kalibratorkonzentration wird 250 / vorgeschlagen. Mit dem hier beschriebenen Verfahren ist es auch für Routinelaboratorien möglich, den Linearitätsbereich des eigenen Gerätes zu überprüfen. Schlüsselwörter: Bilirubin -Neugeborene -Bilirubinometer -Referenzmethode -Richtigkeit

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Calibration of Direct Reading Photometers for the Determination of Neonatal Bilirubin

Cited by 3 publications

References 5 publications

Improvement of Conventional Transcutaneous Bilirubinometry Results in Term Newborn Infants

Improvement of Conventional Transcutaneous Bilirubinometry Results in Term Newborn Infants

Calibrators and Control Samples for Bilirubinometers

Verbesserung der Richtigkeit von Bilirubinometer-Ergebnissen

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