Total Bilirubin Assay Research Articles

Comparative analysis of the quantitative point-of-care CareSTART™ total bilirubin with central laboratory total bilirubin assays in neonatal blood samples.

This study aimed to assess and compare the accuracy of point-of-care CareSTART™ S1 Total Bilirubin test with a central laboratory total bilirubin assay using neonatal samples. This study was conducted using 152 paired measurements obtained from 122 neonates admitted to the neonatal intensive care unit. Total serum bilirubin (TSB) levels assayed with the central laboratory assay, laboratory bilirubinomter, trancutaneous bliribubin (TcB) instrument and CareSTART were compared using Bland-Altman analysis. The mean difference between the CareSTART and TSB values was -1.43 mg/dL and the 95% limit of agreement (LoA) was -4.25 to 1.39 mg/dL. CareSTART tended to underestimate total bilirubin concentrations compared with TcB, however, the LoA was narrower due to the smaller SD of mean difference for CareSTART. The CareSTART Total Bilirubin test provides an accurate alternative to TcB for total serum bilirubin measurement. Given its low-cost, ease-of-use, and portability, the use of CareSTART is expected to provide point-of-care measurements, especially in low-resource settings.

Laboratory assessment of total bilirubin assay in hospitalized adult patients and incidence of Gilbert's syndrome in Saudi Arabia

Laboratory assessment of total bilirubin assay in hospitalized adult patients and incidence of Gilbert's syndrome in Saudi Arabia

Filling in the gaps with non-standard body fluids

ObjectivesBody fluid specimens other than serum, plasma or urine are generally not validated by manufacturers, but analysis of these non-standard fluids can be important for clinical diagnosis and management. Laboratories, therefore, rely on the published literature to better understand the validation and implementation of such tests. This study utilized a data-driven approach to determine the clinical reportable range for 11 analytes, evaluated a total bilirubin assay, and assessed interferences from hemolysis, icterus, and lipemia in non-standard fluids. Design and methodsHistorical measurements in non-standard body fluids run on a Beckman Coulter DxC800 were used to optimize population-specific clinical reportable ranges for albumin, amylase, creatinine, glucose, lactate dehydrogenase, lipase, total bilirubin, total cholesterol, total protein, triglyceride and urea nitrogen run on the Beckman Coulter AU680. For these 11 analytes, interference studies were performed by spiking hemolysate, bilirubin, or Intralipid® into abnormal serous fluids. Precision, accuracy, linearity, and stability of total bilirubin in non-standard fluids was evaluated on the Beckman Coulter AU680 analyzer. ResultsThe historical non-standard fluid results indicated that in order to report a numeric result, 4 assays required no dilution, 5 assays required onboard dilutions and 2 assays required both onboard and manual dilutions. The AU680 total bilirubin assay is suitable for clinical testing of non-standard fluids. Interference studies revealed that of the 11 total AU680 analyte measurements on non-standard fluids, lipemia affected 1, icterus affected 3, and hemolysis affected 5. ConclusionsChemistry analytes measured on the AU680 demonstrate acceptable analytical performance for non-standard fluids. Common endogenous interference from lipemia, icterus, and hemolysis (LIH) are observed and flagging rules based on LIH indices were developed to help improve the clinical interpretation of results.

Analysis of interference effect of cefotiam on total bilirubin assay

血清胆红素检测是诊治肝胆疾病和溶血性疾病必不可少的常规检验项目.Kuenzle用柱层析方法将血清胆红素分为4种组分:游离胆红素(α胆红素)、单结合胆红素(β胆红素)、双结合胆红素(γ胆红素)以及与蛋白呈不可逆结合的胆红素(e胆红素)[1]。

Naproxen Metabolites Interfere With Certain Bilirubin Assays

A recent report indicated significant interference of naproxen with total bilirubin measurement when using the Jendrassik and Grof method. We explored the possibility of avoiding this interference by using a different method. We observed that naproxen has no effect on total bilirubin measurement by any method, but O-desmethylnaproxen (the naproxen metabolite) interfered significantly with total bilirubin assays using the Jendrassik and Grof method (Beckman Coulter [Brea, CA] and Siemens [Tarrytown, NY] bilirubin method). The Roche (Indianapolis, IN) bilirubin assay based on a different method was not affected. When serum samples of 9 patients receiving naproxen were analyzed for total bilirubin level, we observed good correlation in total bilirubin values measured by all 3 methods in 7 of 9 patients with therapeutic naproxen concentrations. In contrast, in 2 patients with elevated naproxen levels, the total bilirubin values observed by using the Beckman and Siemens methods were significantly higher than the value obtained by the Roche assay. The naproxen metabolite interferes with assays based on the Jendrassik and Grof method but not with the Roche bilirubin assay.

Evaluation of hemoglobin interference in capillary heel-stick samples collected for determination of neonatal bilirubin

Objective: In this study, we determined the assay performance criteria necessary to produce acceptable results for ≥ 98% of neonate bilirubin samples collected by capillary heel-stick. Study design and methods: We determined serum free hemoglobin levels in 151 heel-stick serum samples to determine the hemolysis level. We then tested the effect of hemolysis on total bilirubin levels determined by four commercially available assays. Results: The mean level of serum free hemoglobin was 1.62 g/L. Of the serum total bilirubin assays tested, the Total Bilirubin Special (Roche Diagnostics) and the TBILI (Roche Diagnostics) reagents did not show significant interference at the concentrations of free hemoglobin observed in ≥ 98% of heel-stick samples. The Vitros Bu/Bc slide (Ortho-Clinical Diagnostics) showed significant interference only at normal bilirubin concentrations; while the Bilirubin DPD reagent (Amresco Inc.) showed significant interference starting at hemoglobin concentrations of 1.0 g/L. Conclusions: Bilirubin assays that are not sensitive to ∼ 6 g/L free hemoglobin should provide accurate results for most samples obtained via capillary heel-stick. Of the four assays tested, the Bilirubin DPD reagent (Amresco Inc.) was the most susceptible to the presence of free hemoglobin and will result in a higher rejection rate of neonate capillary heel-stick samples.

Paraprotein Interference in Automated Chemistry Analyzers

We read with interest the Technical Brief by Smogorzewska et al. (1) describing an artificially increased total bilirubin in a patient with a monoclonal IgM paraprotein. Monoclonal paraproteins have been shown to artifactually influence several automated assays of different methodologies, including nephelometry, turbidometry, and immunologic assays, by forming precipitates during the assay procedure (2)(3)(4)(5)(6)(7). The total bilirubin assay on the Hitachi 917 automatic chemistry analyzer (Roche Diagnostics) has been reported to yield falsely increased bilirubin values as a result of paraprotein interference (1)(8). Smogorzewska et al. (1) and Pantanowitz et al. (8) described this artifact as rare, but we have identified 6 patients at 2 hospitals with documented paraproteins who had falsely increased serum total bilirubin. Notably, patients with artifactually high total …

Paraprotein interference in automated chemistry analyzers.

Paraproteins can interfere in chemical measurements when they form precipitates during the testing procedure (1)(2)(3)(4)(5)(6)(7)(8)(9). Here we describe ways to identify paraproteins that interfere in methods for bilirubin and HDL on an automated analyzer. The approaches appeared to be effective in identifying these rare cases of interference and did not hinder the autovalidation of appropriately high or low values for either assay. Software analysis and reporting programs currently in use that rely on rigid two-point calculations derived from reaction monitors may be susceptible to errors in analysis. We encountered an artifactually increased total bilirubin concentration and an artifactually low HDL in a patient with a monoclonal IgM paraprotein. The tests were initially performed on plasma samples with the Hitachi 917 automated analyzer (Roche Diagnostics) using the Roche total bilirubin assay and the Roche HDL-C Plus assay. For this patient, the reported total bilirubin was 318 mg/L, direct bilirubin was 2 mg/L, total protein was 127 g/L, and HDL was undetectable. Serum protein electrophoresis revealed a monoclonal IgMκ M component at a concentration of 66 g/L. Similar results were seen on subsequent samples (both in plasma and serum), with a high total bilirubin and undetectable HDL. On a previous admission 2 years before, her total bilirubin concentration had been within the reference interval at 4 mg/L, and her HDL was measured as 390 mg/L by the same assay systems. The Roche total bilirubin assay is a liquid, end-point, chromogenic assay based on a modification of the diazo method (10). The assay uses detergent as the accelerator and to help avoid protein precipitation. After solubilization with this reagent (reagent 1), the diazo reagent (reagent 2) is added to the cuvette to produce a pink color change …

Report of a trial with lyophilised QC sera in the CMCH/ACBI EQAS programmes in India

2000 vials of lyophilized QC of two different levels (low and high) were donated by Roche Diagnostics GmbH, through the IFCC and received by CMCH in June 2001. A total of 240 la boratories were enrolled for this 6 month pilot study. In addition to the 12 analytes in the liquid QC programme, six additional analytes, LDH, triglyceride, urate, total bilirubin, phosphate and amylase were included. It was also possible to measure sodium and potassium by ion selective electrode (ISE) methods in the QC for the first time.The performance of the laboratories for the existing 12 analytes using liquid stabilized QC was compared to the performance using lyophilized QC. Using a statistical comparison of the methodwise mean variance index score (MVIS) values, five assays viz glucose, albumin, cholesterol, and SGOT and SGPT performance was the same in liquid QC and lyophilized QC. Three assays viz urea, calcium and creatinine were significantly better, and 4 assays total protein, sodium, potassium and ALP were significantly worse. However the overall VIS (OMVIS) for the laboratories was the same and the ranking pattern of this 6 month OMVIS was also unaltered.The lyophilized QC scheme highlighted a negative bias between flame and ISE methods for sodium and potassium, and a definite standardization problem in reporting LDH and amylase results, but triglyceride, urate and total bilirubin assays were performing well.It was concluded that the introduction of lyophilized QCs will not cause any deterioration of performance to participating laboratories. Stability of the material seems to be good and the laboratories are generally using a good reconstitution technique.

Artifactual hyperbilirubinemia due to paraprotein interference.

Paraprotein interference in automated chemistry is uncommon. We describe 2 patients with paraproteinemia and elevated total bilirubin levels measured erroneously using the Roche total bilirubin assay. To explain the mechanism of this artifactual hyperbilirubinemia and to determine its frequency in patients with monoclonal or increased immunoglobulins. The assay was performed manually using serum from 2 index patients and from control patients (without M proteins). Total bilirubin was also determined using another manufacturer's assay. A prospective study was then undertaken using serum from 100 consecutive patients with various monoclonal gammopathies and from 13 patients with polyclonal hypergammaglobulinemia and cryoglobulins. For all patients, serum immunoglobulin (Ig) G, IgA, IgM, total and direct bilirubin, creatinine, and a direct spectrophotometric assessment of icterus were measured. After the addition of assay reagents, a white precipitate formed in the reaction mixtures containing serum from the index patients, but not in other samples. This turbidity, rather than the expected color change to pink, increased the absorbance and falsely elevated the total bilirubin value. Serum from both index patients was anicteric, their direct bilirubin measurements were unaffected, and total bilirubin measured using an alternate assay was normal. Among the 113 patients studied, no additional spurious total bilirubin values were detected. Paraprotein interference with the Roche automated total bilirubin assay is caused by precipitate formation. This interference is rare and probably idiosyncratic. Spurious hyperbilirubinemia from paraprotein interference may cause clinical confusion. If artifactual elevation of total bilirubin is suspected, the laboratory should examine the specimen for icterus (manually or by spectrophotometry) or measure total bilirubin using a different method.

Bilirubin measured on a blood gas analyser: a suitable alternative for near-patient assessment of neonatal jaundice?

The reliability of a recently released total bilirubin assay for a blood gas analyser was assessed in two Australian hospital laboratories. The instrument computes total bilirubin concentration from multi-wavelength absorbance measurements of undiluted whole blood or plasma. Performance of the Radiometer ABL 735 blood gas analyser bilirubin method (software version 3.6) was compared with a proven Roche diazo method for Hitachi analysers, calibrated using primary standards prepared from NIST SRM 916a bilirubin. Acceptable bilirubin results were found over a wide concentration range for most neonatal samples of whole blood or plasma. For adult specimens, bilirubin results were approximately 10% lower on the blood gas analyser. Within-run imprecision (whole blood) was < 2.5%, between-day imprecision (synthetic controls) < 1.0%, and the bilirubin assay for both whole blood and plasma was linear to 1,000 micromol/L. Using sampling options from 35 microL to 195 microL, bilirubin results differed by less than 3%, with a 95 microL syringe option producing the highest results. We conclude that the Radiometer ABL 735 bilirubin assay is suitable for near-patient assessment of neonatal jaundice using whole blood, thus eliminating the need for sample centrifugation. Verification using laboratory methods can be used when required. A positive correction of approximately 10% is required for adult specimens to conform with Hitachi results (SRM 916a calibration), possibly due to the optical characteristics of the higher proportion of conjugated bilirubin and other substances present in most adult samples.

Fluorescence reaction of bilirubin with zinc ion in dimethyl sulfoxide and its application to assay of total bilirubin in serum

A new fluorimetric method is described for the determination of total bilirubin in serum. The fluorescence with maximum excitation and emission at 470 and 545 nm, respectively, is based on the reaction of bilirubin with zinc acetate in dimethyl sulfoxide (DMSO). Serum (10 μl) is added to 2.5 ml of DMSO solution containing zinc acetate (0.01 M) and Tris (0.2 M). After 60 min, at 37°C, the fluorescence is measured. The blank is obtained by mixing serum (10 μl) and Tris-DMSO solution (2.5 ml) without zinc acetate. The method gave a linear calibration for 0.1–5 mg dl −1 bilirubin, a 3.3 σ detection limit of 5 μg dl −1 and relative standard deviations for bilirubin in control sera of 1–2% ( n=10). It is simple, specific and sensitive, and showed good correlation with the usual diazo-coupling method.

The Analysis of Bilirubin in Serum

The most widely used methods for the assay of total bilirubin in serum are based on a coupling reaction with various diazo dyes in the presence of an accelerating agent. The 'direct' reaction, without accelerator, gives a good estimate of the conjugated and protein bound (delta) species of bilirubin only if carefully standardized reaction conditions are used. Enzymatic methods based on bilirubin oxidase appear to give similar results, for both total and direct bilirubin, and through difficult to calibrate, spectrophotometric methods can also give reliable results for total bilirubin at the higher concentrations seen in neonates. More sophisticated HPLC or dry-slide techniques are required for the specific assay of the various conjugated and protein-bound species of bilirubin in serum.

Influence of ambient temperature on the Ektachem DT60 results for total bilirubin and total protein.

We evaluated the Kodak Ektachem DT60 analyzer with the DTE module in a two-month clinical trial before its introduction in the Netherlands. At ambient temperatures that differed from that at which the DT60 was calibrated, aberrant behavior for total bilirubin and total protein assays was observed. At subnormal temperatures the former gave higher results than expected, and the latter, lower results. We found a similar effect for total protein determined by the manual biuret reaction at different temperatures, when results were calculated from calibration at a fixed temperature. Total bilirubin assayed by the manual diazobilirubin method showed no such effect. Although the DT60 analyzer is equipped with a temperature-regulated incubator, we conclude that the manufactures's recommended room temperature range for these assays should be narrowed and the three-month calibration period adjusted according to external circumstances.

Hemoglobin interference with the BMD total bilirubin assay in the Hitachi 705 analyzer, and its relation to the hemolytic index.

Hemoglobin interference with the BMD total bilirubin assay in the Hitachi 705 analyzer, and its relation to the hemolytic index.

Assessment of the fundamental accuracy of the Jendrassik-Gróf total and direct bilirubin assays.

Using unconjugated bilirubin (Bu) and authentic human disconjugated bilirubin (dBc) supplemented in low-bilirubin serum pools, we have directly verified for the first time that the Jendrassik-Gróf total bilirubin assay modified after Doumas et al. (Clin. Chem. 19: 984-993, 1973) detects Bu and dBc quantitatively, in Bu-equivalent concentrations relative to gravimetric concentration assignment reinforced with quantification by nuclear magnetic resonance (Wu et al., Clin. Chem. 26: 1323-1335, 1980). By contrast, the Jendrassik-Gróf direct bilirubin assay (also modified after Doumas) quantifies only 70 +/- 5% of the gravimetrically determined dBc as Bu equivalents. By using Bu and dBc (instead of Bu only, as is routinely done) to calibrate the responses of the total and direct bilirubin assays, the analyses of Bu and dBc become much more quantitative. We mathematically explored the meanings of the conventional terms total, direct, and indirect bilirubins. The clinical and diagnostic implications of our observations are discussed.

Dosage fluorimetrique de la bilirubine

Resume A simple and sensitive assay of total bilirubin in serum is presented. 50 μl serum are mixed with 0.6 ml H 3 PO 4 85%, 3 ml water are added after 1 min or more and the fluorescence is measured in a filter fluorimeter. Maximum excitation and fluorescence wavelengths are 435 and 500 nm respectively. Blanks are made by mixing serum and water first, and then adding H 3 PO 4 . The method shows good correlation with the usual diazo-coupling method. It is highly precise, even in the normal range, and specific. The presence of albumin is necessary for the intensification of fluorescence; serum samples containing more than no mg/1 bilirubin are diluted with a 6% solution of bovine albumin. The assay has also been adapted to urine: 50 μl urine are mixed with 50 μl 6% albumin solution and 0.6 ml H 3 PO 4 85%; after 1 min or more, 3 ml of water are added and the fluorescence is measured. Blanks are made as above. Values for total bilirubin in the serum of 36 healthy individuals ranged from 3.5 to 9.9 mg/1.