Operational impact of using a vanadate oxidase method for direct bilirubin measurements at an academic medical center clinical laboratory

Spectral analysis with highly collimated mini-LEDs as light sources for quantitative detection of direct bilirubin

Because the human eye cannot visually detect the results of direct bilirubin test papers accurately and quantitatively, this study proposes four different highly collimated mini light-emitting diodes (HC mini-LEDs) as light sources for detection. First, different concentrations of bilirubin were oxidized to biliverdin by FeCl3 on the test paper, and pictures were obtained with a smartphone. Next, the red, green, and blue (RGB) channels of the pictures were separated to average grayscale values, and their linear relationship with the direct bilirubin concentration was analyzed to detect bilirubin on the test paper noninvasively and quantitatively. The experimental results showed that when green HC mini-LEDs were used as the light sources and image analysis was performed using the G channel, for a direct bilirubin concentration range of 0.1-2 mg/dL, the G channel determination coefficient (R2) reached 0.9523 and limit of detection was 0.459 mg/dL. The detection method proposed herein has advantages such as rapid analysis, noninvasive detection, and digitization according to RGB grayscale changes in the images of the detection test paper.

Reducing Specimen Rejection Rates Using Concentration-Dependent Hemolysis Rejection Thresholds

BACKGROUND

Using middleware solutions, it is possible to implement concentration-dependent analyte-specific hemolysis rejection limits. This makes day-to-day reporting of clinical specimens more efficient and potentially lowers sample rejection rates compared to a "one-size-fits-all" approach (i.e., solely based on a single cutoff provided in the package insert).

METHODS

Hemolysis interference studies were performed at multiple analyte concentrations for three frequently ordered tests. For each assay, concentration-dependent hemolysis rejection limits were designed based on the total allowable error (TAE) for the analyte as well as the clinical significance of such incurred inaccuracy at the respective concentrations. In general, the following rationale was used: if the interference exceeds 10% (or package insert cutoffs), a comment is placed on the result. If the interference exceeds the TAE, the result will not be reported. Reduction in specimen rejection rates were estimated by comparing the incurred specimen rejection rates when package inserts' vs concentration-dependent hemolysis interference limits were applied to a data set in our institute during a three-month period.

RESULTS

Concentration-dependent analyte-specific hemolysis rejection thresholds were designed for three commonly ordered assays that are especially susceptible to hemolysis interference. It is estimated that these novel thresholds for aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and direct bilirubin (DBIL) reduced specimen rejection rates from 9.3% to 1.3%, 31.4% to 4.8%, and 19.9% to 7.1%, respectively.

CONCLUSIONS

Concentration-dependent analyte-specific hemolysis rejection thresholds for three commonly ordered assays can reduce rejection rates without significantly compromising the quality of test results.

Noninvasive direct bilirubin detection by spectral analysis of color images using a Mini-LED light source

Urine test paper is a standard, noninvasive detection method for direct bilirubin, but this method can only achieve qualitative analysis and cannot achieve quantitative analysis. This study used Mini-LEDs as the light source, and direct bilirubin was oxidized to biliverdin by an enzymatic method with ferric chloride (FeCl₃) for labeling. Images were captured with a smartphone and evaluated for red (R), green (G), and blue (B) colors to analyze the linear relationship between the spectral change of the test paper image and the direct bilirubin concentration. This method achieved noninvasive detection of bilirubin. The experimental results demonstrated that Mini-LEDs can be used as the light source to analyze the grayscale value of the image RGB. For the direct bilirubin concentration range of 0.1-2 mg/dL, the green channel had the highest coefficient of determination coefficient (R²) of 0.9313 and a limit of detection of 0.56 mg/dL. With this method, direct bilirubin concentrations higher than 1.86 mg/dL can be quantitatively analyzed with the advantage of rapid and noninvasive detection.

Use of a Vanadate Oxidation Conjugated Bilirubin Assay to Reduce Test Cancellations Resulting from Hemolyzed Specimens in Pediatric Patients

OBJECTIVES

We sought to replace the highly hemolysis-susceptible diazo conjugated bilirubin (Bc) assay with the more robust vanadate oxidation method and determine its impact on test cancellation in the pediatric population.

METHODS

Analytical validation of the Randox vanadate assay and comparison with the Roche diazo method were performed. The frequency of pediatric sample cancellation because of hemolysis was compared between the diazo and vanadate methods by retrospective analysis of clinical test data.

RESULTS

The vanadate assay demonstrated no clinically significant interference from hemolysis up to a hemolysis index of 1,300 (approximately 13 g/L hemoglobin). There was a strong correlation with the diazo method (r2 = 0.97) but with a positive slope bias of 1.27. Implementing the vanadate method resulted in a significantly lower proportion of pediatric samples cancelled because of hemolysis compared with the diazo method (0.6% of 688 patients vs 30.6% of 10,464 patients, respectively; P < .001), with a 0.6% (n = 513) vs 43.2% (n = 6,464) reduction in test cancellations (P < .001) for children younger than 6 months of age.

CONCLUSIONS

The vanadate method showed robust performance against hemolysis. Its implementation resulted in a significant decrease in pediatric tests cancelled because of hemolysis.

Using Blue Mini-LEDs as a Light Source Designed a Miniaturized Optomechanical Device for the Detection of Direct Bilirubin

This study developed a miniaturized optomechanical device (MOD) for the feasibility study of direct bilirubin in urine using high-collimation blue mini-light-emitting diodes (Mini-LEDs) as the light source. The constructed MOD used optical spectroscopy to analyze different concentrations of direct bilirubin using the absorbance spectrum to achieve a noninvasive method for detection. The experimental results showed that between the absorbance and different concentrations of direct bilirubin at the blue Mini-LEDs central wavelength (462 nm) was the optimum fitting wavelength; in the direct bilirubin concentration range from 0.855 to 17.1 μmol/L, the coefficient of determination (R²) was 0.9999, the limit of detection (LOD) of 0.171 μmol/L, and the limit of quantitation (LOQ) of 0.570 μmol/L. Therefore, we propose using blue Mini-LEDs as a light source to design a MOD to replace the invasive blood sampling method with a spectroscopic detection of direct bilirubin concentration corresponding to absorbance.

Relationship between serum indirect bilirubin levels and skeletal muscle mass in older male and female patients with type 2 diabetes

Objective

We previously showed that low serum bilirubin levels are associated with disability in quality of daily living in older patients with diabetes. However, the underlying mechanism is not fully understood. The aim of this study is to assess the relationship between serum bilirubin levels and skeletal muscle mass in older patients with type2 diabetes.

Methods

A total of 272 older patients with type2 diabetes (152 male and 120 female) aged 60 years and over were continuously recruited from April 2020 to July 2020. Body composition was evaluated by bioelectrical impedance analysis. The skeletal muscle mass index (SMI) was calculated as appendicular muscle mass divided by height squared (m²).

Results

The SMI was markedly lower in old-old patients (aged 75 years and over) than in young-old patients (aged 60–74 years) in both male and female (7.1 ± 0.8 kg/m² vs 7.6 ± 0.9 kg/m², P<0.001; 5.5 ± 0.9 kg/m² vs 6.3 ± 0.8 kg/m², P<0.001, respectively). Multivariate regression analysis showed that the SMI was associated with body mass index (BMI) (p<0.001) and age (p = 0.048) in male young-old patients, while it was associated with BMI (p<0.001), age (p = 0.008), and serum indirect bilirubin levels (p = 0.038) in male old-old patients. In female, the SMI was associated with BMI (p<0.001) and age (p = 0.042) in young-old patients and associated with BMI alone (p<0.001) in old-old patients.

Conclusion

Serum indirect bilirubin levels may be associated with the decreased skeletal muscle mass in male older patients (aged 75 years and over) with type 2 diabetes.

Frequency of icteric interference in clinical chemistry laboratory tests and causes of severe icterus

Objectives

The aims of this study were to identify the causes of severe icterus in an academic medical center patient population and to assess the impact of icterus on clinical chemistry testing using assay package insert thresholds.

Design

and Methods: In this retrospective study at an academic medical center core clinical laboratory, icteric, hemolysis, and lipemia indices were available for all serum and plasma chemistry specimens analyzed on Roche Diagnostics cobas 8000 analyzers over a 12-month period, encompassing 414,502 specimens from 94,081 unique patients (51,851 females; 42,230 males) including children, inpatient, outpatient, and emergency department patients. Extensive chart review was done for all 57 patients (4 pediatric, 53 adult; 534 total specimens) who had one or more samples with an icteric index of 40 or higher (defined as severe icterus).

Results

Specimen icteric index exceeded package insert icteric index thresholds in 0.14% of clinical chemistry assays, with the highest number of instances for creatinine (1358 samples, 0.6% of total tests), total protein (1194 samples, 2.2%), and ammonia (161 samples, 3.9%). The 57 patients with an icteric index of 40 or higher accounted for 49.7% of all instances where the icteric index exceeded the specific assay package insert limit. The most common etiologies of this group of 57 patients were alcohol-related liver disease (34 patients), biliary tract disease (7 patients), and neoplasms (6 patients).

Conclusions

Approximately half of all instances where specimen icteric index exceeded assay package insert thresholds occurred in a small cohort of patients with severe liver/biliary tract disease.

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Specimen icteric indices exceeded package insert icteric index thresholds for 0.14% of clinical chemistry tests ordered at an academic medical center.

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Icteric interference exceeding package insert thresholds had the most overall occurrences for enzymatic creatinine, total protein, and ammonia.

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Only 57 of 94,081 unique patients (0.06%) with severe icterus accounted for nearly half of instances where the icteric index exceeded the package insert limit for a specific assay.

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The small cohort of patients with severe icterus had high mortality generally associated with cirrhosis, biliary disease, or aggressive metastatic cancer.

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Icteric indices exceeding 20 were mostly comprised of patients with predominantly conjugated hyperbilirubinemia.

An effective enzymatic assay for pH selectively measuring direct and total bilirubin concentration by using of CotA

In this study, we aimed to develop B. subtilis spore coat protein A (CotA) for the enzymatic determination of bilirubin. Firstly, molecular docking and oxidation kinetic analysis confirmed the feasibility of CotA for oxidizing bilirubin. Secondly, CotA showed pH-preferable oxidization performance to direct bilirubin (DB) in acidic conditions and an alkaline-catalytic oxidation capacity to total bilirubin (TB). Mechanism analysis results confirm that the conformational changes of CotA, DB and UB caused by pH changes are responsible for the selective oxidation of DB and TB by CotA. Then, CotA exhibits better structural characteristics and enzymatic performance than M. verrucaria-derived bilirubin oxidase (Mv-BOD). Besides, the strong anti-interference ability helps CotA adapt to complex catalytic environment in the detection of DB and TB. Our results prove that CotA can be used as a promising candidate bio-enzymatic detection reagent for DB and TB.

Dispersive Liquid-Liquid Microextraction Based on Ionic Liquid and Spectrophotometric Determination of Bilirubin in Biological Samples

Background:

An Ionic Liquid-based based Dispersive Liquid-Liquid Microextraction (IL-DLLME) method was not applied to preconcentration and determination of bilirubin. Ionic Liquids (ILs) are new chemical compounds. In recent years, Ionic Liquids (ILs) have been employed as alternative solvents to toxic organic solvents. Due to these perfect properties, ILs have already been applied in many analytical extraction processes, presenting high extraction yield and selectivity for analytes.

Methods:

In this study, IL-DLLME was applied to biological samples (urine and serum) for the spectrophotometric detection of bilirubin. For bilirubin analysis, the full-color development was based on the reaction with periodate in the presence of hydrochloric acid. The high affinity of bilirubin for the ionic liquid phase gave extraction percentages above 98% in 0.3 M HCl solution.

Results:

Several IL-extraction parameters were optimized and room temperature ionic liquid 1-butyl- 1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide and ethanol were used as extraction and disperser solution. The linear range was found in the range of 0.5-6.0 μM (0.3-3.5 μg mL-1) and the limits of detection of the proposed method was 0.5 μM (0.3 μg mL-1). The proposed method was applied for the preconcentration and separation of trace bilirubin in real urine samples. Also, the recoveries for bilirubin in spiked biological samples (urine and serum) were found to be acceptable, between 95-102%.

Conclusion:

The proposed IL-DLLMEapproach was employed for the enrichment and determination of trace levels of bilirubin in urine samples using NaIO4 as an oxidizing agent and Uv-vis spectrophotometric detection. The periodate oxidation of bilirubin is rapid, effective, selective, and simple to perform. The method contains only HCl, NaOI4, and an anionic surfactant. The method may be useful for economizing in the consumption of reagents in bilirubin determining. The IL-DLLMEmethod ensures a high yield and has a low toxicity no skin sensitization, no mutagenicity and no ecotoxicity in an aquatic environment since only very low quantities of an IL is required. For full-color formation, no any extra auxiliary reagents are required. Besides, the IL-DLLME technique uses a low-cost instrument such as Uv-vis which is present in most of the medical laboratories.

Newborns bilirubin concentration determined by different methods in relation to hematocrit and albumin level

Background

Monitoring of bilirubin is essential during early neonatal life. Bilirubin in high concentration is toxic to the brain and might cause irreversible neurological damage. Several different methods for bilirubin determination are available nowadays, but inconsistent results may be obtained. The study aimed to compare dry chemistry methods with vanadate oxidation method for bilirubin determination in relation to hematocrit and albumin level in neonates and infants.

Methods

The study included 98 consecutive serum samples from newborns and infants (47 boys and 51 girls, mean age 19 ± 15 days) treated in the University Children's Hospital in Krakow. Total bilirubin (TBil) and neonatal bilirubin (NBil) concentration were measured by dry chemistry analyser (Vitros 4600, Ortho Clinical Diagnostics Inc.). Total bilirubin (TBil_V) was also measured using vanadate oxidation method (Cormay, Poland). Albumin concentration and blood morphology have been routinely determined in all children.

Results

No significant differences between the mean value of NBil (69.00 ± 67.76 μmol/L), TBil (81.26 ± 70.13 μmol/L) and TBilV (75.90 ± 60.62 μmol/L) were noticed. High coefficient correlation between NBil and TBil as well as between NBil and TBil_V were noticed (Pearson's analysis, r = 0.99, r = 0.97, respectively; p < 0.0001 in both cases). There was a positive correlation between the difference (TBil_V - NBil) and hematocrit (p < 0.009, r = 0.2664).

Conclusions

In newborns and infants the same method for bilirubin determination should be used when the concentration of bilirubin is monitored. When using vanadate oxidation method for bilirubin determination, hematocrit value should be taken into account when results are interpreted.

Systemic alterations induced by phospholipase A2 , BmooTX-I, isolated from Bothrops moojeni snake venom

Ophidic accidents are among the problems of public health in Brazil. The components from bothropic venom are responsible for many systemic clinical complications resulting from envenomation. The present work aimed to analyse the systemic changes induced in mice after intraperitoneal administration of BmooTX-I, a myotoxic acidic phospholipase A₂ isolated from Bothrops moojeni venom. Urinalysis was performed and the following plasma biochemical markers were documented: urea, creatinine and uric acid (renal function); glucose and amylase (pancreatic function); alanine aminotransferase, alkaline phosphatase and gamma-GT (intra- and extrahepatic function); creatine kinase and enzymatic lactate (muscle function). Our results showed that after the intraperitoneal injection of BmooTX-I the urine of these animals showed glycosuria, proteinuria, haematuria, bacteriuria, bilirubinuria, polyuria and nitrite. The plasma biochemical analysis showed alterations in levels of urea, creatinine and uric acid. Amylase concentration was not altered significantly, but the plasma glucose increased significantly compared to controls. The plasma levels of alanine aminotransferase and alkaline phosphatase decreased and increased, respectively, in these same animals. On the other hand, the plasma γGT concentration did not undergo significant modification compared to the control group. The plasma concentration of CK increased, while the enzymatic lactate concentration decreased after the injection of the BmooTX-I. Therefore, in mice BmooTX-I is capable of causing systemic alterations which manifest as renal, muscular, hepatic and pancreatic impairment.

Using Focused Laboratory Management and Quality Improvement Projects to Enhance Resident Training and Foster Scholarship

Training in patient safety, quality, and management is widely recognized as an important element of graduate medical education. These concepts have been intertwined in pathology graduate medical education for many years, although training programs face challenges in creating explicit learning opportunities in these fields. Tangibly involving pathology residents in management and quality improvement projects has the potential to teach and reinforce key concepts and further fulfill Accreditation Council for Graduate Medical Education goals for pursuing projects related to patient safety and quality improvement. In this report, we present our experience at a pathology residency program (University of Iowa) in engaging pathology residents in projects related to practical issues of laboratory management, process improvement, and informatics. In this program, at least 1 management/quality improvement project, typically performed during a clinical chemistry/management rotation, was required and ideally resulted in a journal publication. The residency program also initiated a monthly management/informatics series for pathology externs, residents, and fellows that covers a wide range of topics. Since 2010, all pathology residents at the University of Iowa have completed at least 1 management/quality improvement project. Many of the projects involved aspects of laboratory test utilization, with some projects focused on other areas such as human resources, informatics, or process improvement. Since 2012, 31 peer-reviewed journal articles involving effort from 26 residents have been published. Multiple projects resulted in changes in ongoing practice, particularly within the hospital electronic health record. Focused management/quality improvement projects involving pathology residents can result in both meaningful quality improvement and scholarly output.