Clinical Chemistry Laboratory Research Articles

The diagnostic accuracy of quality control rules

Internal quality control in clinical chemistry laboratories are based on analyzing samples of stable control materials among the patient samples. The control results are interpreted by using quality control rules that usually are designed to detect systematic errors. The best rules have a high probability of error detection (Ped), i.e. to detect the maximal allowable (critical) systematic error and a low probability of false rejection (Pfr, false alarm). In this work we show that quality control rules can be represented by points on a ROC curve which appears when Ped is plotted against Pfr and only the control limit is varied. Further, we introduce a new method for choosing the optimal control limit, analogous to choosing the optimal operating point on the ROC curve of a diagnostic test. This decision needs knowledge of the pretest probability of a critical systematic error, the benefit of detecting it when it occurs and the cost of false alarm. The ROC curve analysis showed that if rules based on N = 2 are used, mean rules outperform Westgard rules because the ROC curve of the mean rules was lying above the ROC curves of the Westgard rules. A mean rule also had a lower maximum expected increase in the number of unacceptable patient results reported during the presence of an out-of-control error condition (Max E(NUF)) than comparable Westgard rules.

Application of DMAIC methodology to reduce pre-analytical errors in a tertiary hospital clinical chemistry laboratory in India

Application of DMAIC methodology to reduce pre-analytical errors in a tertiary hospital clinical chemistry laboratory in India

Evaluation of newborn screening program for maple syrup urine disease for optimization of amino acid ratio cutoffs: Experience from a single clinical chemistry laboratory

Evaluation of newborn screening program for maple syrup urine disease for optimization of amino acid ratio cutoffs: Experience from a single clinical chemistry laboratory

Quality control in the Netherlands; todays practices and starting points for guidance and future research.

Adequate analytical quality of reported results is primarily ensured by performing internal quality control (iQC). Currently, several different iQC practices are in use. As a prelude to the revision of a Dutch guidance document on analytical QC, a questionnaire was sent out to gain insights in the applied practices and the need for guidance. A questionnaire, containing 20 multiple-choice questions with possibilities for explanation and comment on iQC practices and aspects was distributed to all clinical chemistry laboratories within the Netherlands. Results were reported descriptively. Responses were received from 27 clinical laboratories (response 43 %). In 30 % the iQC was based on the analytical characteristics only, while 30 % used a 6-Sigma method, 19 % risk-based beyond 6-Sigma and 22 % used an alternative approach. 89 % of laboratories used a virtual analyzer model for iQC setup within one or more laboratory sites. Practices for determining standard deviation (SD) values included determining SD for each new iQC material (35 %), using historical SD values for new materials (35 %), and incorporating clinical tolerances into the SD value (31 %). Furthermore, 44 % of laboratories used patient moving averages for one or more tests. Daily iQC management was based on either "traffic lights" indicating in or out of control status, and review of all QC charts, often using multiple software systems. A large heterogeneity of iQC practices in clinical laboratories was observed in the Netherlands. Several starting points for further research and/or guidance were identified, particularly in relation to the determination of SD values, the virtual analyzer model and methods to ensure analyzer equivalence.

Total Laboratory Automation in Clinical Microbiology: A Note on Needs, Challenges, and Applications in a Pandemic Scenario

Recently, an increasing number of publications on automation in diagnostic laboratories, especially in microbiology, has illustrated its potential impact on modern medicine by enhancing the overall quality of culture-based microbiology testing. In the context of clinical microbiology, total laboratory automation (TLA) is now defined as automating the testing workflow, which comprises all phases from sample inoculation to outcome analysis. Hence, there is a need to design or implement proper laboratory automation management processes to enhance workflow, reduce analysis time, and deliver high-quality results without delay in treatment initiation. This review-cum-perspective article highlights the need and current advancements in diagnostic microbiology automation that could revolutionize laboratory operations in healthcare settings. Automation of the workflow is a crucial advancement in the recent history of laboratory diagnostics that unites many diagnostic specializations into a single track to increase the effectiveness, administration, standardization, reliability, and safety of lab tests. While clinical chemistry laboratories adopted and deployed laboratory automation decades earlier, the process of implementing them into routine clinical microbiological practices has several bottlenecks and is still a lengthy process and fraught with technical and regulatory challenges. Moreover, due to outbreaks including the COVID-19 pandemic of recent times, testing volumes are increasing, and automation could probably be a great solution for small and mid-sized laboratories. This article lists the TLA remedies and the specimen-processing tools that are presently available. The need and challenges to implementing automation in microbiological laboratories are discussed with a note on applications in pandemic scenarios.

Validation of the efficacy of pooled serum for serum glucose inhouse quality control material in comparison with commercial internal quality control in clinical chemistry laboratory

BackgroundThis study aimed to create an in-house glucose quality control material for humans, addressing the challenge of obtaining high-cost commercially prepared quality control materials in developing countries. MethodsAn in-house quality control material for glucose was prepared using a pooled serum sample and analyzed using a fully automated chemistry analyzer following the ISO 80 guidelines. The mean, standard deviation (SD), and coefficient of variance were calculated from the first 30 days of measurement, and the variability was checked over eight months using SPSS software. The study used Pearson's correlation with a 95% confidence interval and a P-value less than 0.05, which was statistically significant. ResultsThe average mean ± SD of human serum glucose was 185.2 ± 8.4 mg/dL, indicating that the precision between each measurement was better. The prepared in-house quality control material was stable for approximately five months without any significant change in the serum glucose concentration (mg/dl) (p-value<0.05). ConclusionsThe study suggests that room-temperature, 2–8 °C, and −20 °C to −30 °C storage of human serum samples for glucose analysis is a viable option, with stable glucose concentrations for up to 30 days. Pooled serum is a cost-effective method for in-house quality control, especially in resource-limited laboratories.

Precision Matters: Repeatability and Reproducibility of Total PSA and Homocysteine Measurements in Alinity i-System

Introduction: The precision of test measurements is critical in clinical diagnostics, especially for biomarkers like total PSA and homocysteine, which are essential to disease assessment. Using the CMIA approach, this study investigates the repeatability and reproducibility of these biomarkers on the Abbott Alinity system.&#x0D; Materials and methods: The present study was conducted in the clinical chemistry laboratory at Mohammed VI University Hospital of Oujda. The evaluation of the Alinity i-system's analytical performance for total PSA and homocysteine focused on assessing repeatability and intermediate fidelity. The assessment followed the protocols and guidelines established by the French Society of Clinical Biology (SFBC).&#x0D; Results: Our analysis yielded favorable findings regarding the performance of the Alinity assays. The coefficients of variation for both the intra-assay and inter-assay precision were less than 5.89% and 4.29%, respectively. These findings underscore the tests' precision and consistency, affirming the CMIA method's reliability in accurately measuring total PSA and homocysteine levels.&#x0D; &#x0D; Conclusion: Our assessment of the Alinity i-system for total PSA and homocysteines showed significant analytical performance. Yet, limitations due to excluding critical parameters hindered a comprehensive evaluation. Addressing these in future investigations is crucial for upholding high diagnostic standards.

Insights from semi-structured interviews on integrating artificial intelligence in clinical chemistry laboratory practices

BackgroundArtificial intelligence (AI) is gradually transforming the practises of healthcare providers. Over the last two decades, the advent of AI into numerous aspects of pathology has opened transformative possibilities in how we practise laboratory medicine. Objectives of this study were to explore how AI could impact the clinical practices of professionals working in Clinical Chemistry laboratories, while also identifying effective strategies in medical education to facilitate the required changes.MethodsFrom March to August 2022, an exploratory qualitative study was conducted at the Section of Clinical Chemistry, Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan, in collaboration with Keele University, Newcastle, United Kingdom. Semi-structured interviews were conducted to collect information from diverse group of professionals working in Clinical Chemistry laboratories. All interviews were audio recorded and transcribed verbatim. They were asked what changes AI would involve in the laboratory, what resources would be necessary, and how medical education would assist them in adapting to the change. A content analysis was conducted, resulting in the development of codes and themes based on the analyzed data.ResultsThe interviews were analysed to identify three primary themes: perspectives and considerations for AI adoption, educational and curriculum adjustments, and implementation techniques. Although the use of diagnostic algorithms is currently limited in Pakistani Clinical Chemistry laboratories, the application of AI is expanding. All thirteen participants stated their reasons for being hesitant to use AI. Participants stressed the importance of critical aspects for effective AI deployment, the need of a collaborative integrative approach, and the need for constant horizon scanning to keep up with AI developments.ConclusionsThree primary themes related to AI adoption were identified: perspectives and considerations, educational and curriculum adjustments, and implementation techniques. The study’s findings give a sound foundation for making suggestions to clinical laboratories, scientific bodies, and national and international Clinical Chemistry and laboratory medicine organisations on how to manage pathologists’ shifting practises because of AI.

Simple and Cost-Effective Quantum Dot Chemodosimeter for Visual Detection of Biothiols in Human Blood Serum.

An emission "turn-off" chemodosimeter for the naked-eye detection of biothiols using silica-overcoated cadmium selenide quantum dots is developed. Hole scavenging by the thiol group of cysteine, homocysteine, or glutathione on interaction with quantum dots resulted in an instant and permanent emission quenching under physiologically relevant conditions. Also, the emission suppression is so specific that thiols and substituted thiols (methionine and cystine) can easily be distinguished. A pilot experiment for the visual detection of serum thiols in human blood was also conducted. Densitometry analysis proved the potential of this system as a new methodology in clinical chemistry and research laboratories for routine blood and urine analyses using a simple procedure. This method enables one to visually distinguish biothiols and oxidized biothiols, whose ratio plays a crucial role in maintaining "redox thiol status" in the blood.

SIX SIGMA METRICS: INDICATOR OF QUALITY ASSURANCE FOR CLINICAL BIOCHEMSITRY

Introduction: In present scenario Quality is the important aspect of laboratory practices. Mostly internal and external quality control are utilized to maintain quality in laboratory. Quality assurance of laboratory services is the need of present time in health care which require Quality Planning, Quality Control (QC), Quality Assessment (QA) and Quality Improvement . Aims &amp; Objectives: 1. To quantify the defects and errors in analytical phase of laboratory testing by sigma metrics and to represent the calculated sigma value. 2. Application of six sigma test in laboratory with the IQC and EQAS to maintain quality laboratory services. Methodology: Study was conducted at Clinical Biochemistry Laboratory, GMC Akola. We run IQC samples on daily basis and EQAS samples are running on monthly basis. Retrospectively we utilized data of IQC and EQAS from January to October 2023 for 16 Biochemical Analytes. Sigma metrics for each parameter was calculated. Result: The sigma metrics for IQC indicated that 1 out of 16 analytes qualified six sigma quality performance. Of these 15 analytes performance with sigma metrics was beteween three and six. We found different sigma value like more than6 for only HDL cholesterol and more than 3 for Amylase, Total Bilirunbin, Creatinine, Cholesterol, Glucose, Phosphorus, total Protein , SGPT , TG, UA, Urea, SGOT, which is among the acceptable range of performance. Conclusion: In our study sigma value was highest for HDL cholesterol and other 15 analytes show sigma value between 3 to 6 which is acceptable range. Sigma analysis is a continuous procedure and by taking the help of method decision chart we can improve on decision on making in clinical chemistry laboratory regarding optimising QC procedure.

Sigma Metrics Assessment as Quality Improvement Methodology in a Clinical Chemistry Laboratory

Sigma Metrics Assessment as Quality Improvement Methodology in a Clinical Chemistry Laboratory

Biochemical diagnosis of congenital disorders of glycosylation.

Congenital disorders of glycosylation (CDG) are one of the fastest growing groups of inborn errors of metabolism, comprising over 160 described diseases to this day. CDG are characterized by a dysfunctional glycosylation process, with molecular defects localized in the cytosol, the endoplasmic reticulum, or the Golgi apparatus. Depending on the CDG, N-glycosylation, O-glycosylation and/or glycosaminoglycan synthesis can be affected. Various proteins, lipids, and glycosylphosphatidylinositol anchors bear glycan chains, with potential impacts on their folding, targeting, secretion, stability, and thus, functionality. Therefore, glycosylation defects can have diverse and serious clinical consequences. CDG patients often present with a non-specific, multisystemic syndrome including neurological involvement, growth delay, hepatopathy and coagulopathy. As CDG are rare diseases, and typically lack distinctive clinical signs, biochemical and genetic testing bear particularly important and complementary diagnostic roles. Here, after a brief introduction on glycosylation and CDG, we review historical and recent findings on CDG biomarkers and associated analytical techniques, with a particular emphasis on those with relevant use in the specialized clinical chemistry laboratory. We provide the reader with insights and methods which may help them properly assist the clinician in navigating the maze of glycosylation disorders.

THE DIFFERENCES OF HEMATOCRIT LEVEL IN IMMEDIATE AND DELAYED BLOOD SAMPLES ON MICROHEMATOCRIT METHOD

Background: Hematology specimen examination should be performed at room temperature in less than 2 hours. Recommended specimen storage temperatures are in the range of 2°- 6°C. However, examining laboratory samples with uncertain storage time and temperature is often delayed. Aims: To determine the difference between the hematocrit values of blood samples examined immediately and those that were delayed for more than 2 hours at room temperature. Methods: This study was conducted from April to June 2023 at the Clinical Chemistry Laboratory of Universitas Bali Internasional. A total of 24 venous blood samples were grouped into three treatment groups that were stored for 3 hours (P1), 6 hours (P2), and 12 hours (P3) at room temperature (18-220C), and one control group was examined immediately. Data were analyzed using the Mann-Whitney U test (α=0.05). The results: Statistical tests showed that the comparison of control with P1 was not significantly different (p=0.313), while the comparison of control with P2 (p=0.003) and the control with P3 (p=0.000) was significantly different. Conclusions: There was no significant difference in hematocrit values between blood samples examined immediately and blood samples delayed for 3 hours. Significant differences in hematocrit values were shown in comparing blood samples examined immediately with blood samples delayed for 6 hours and examined immediately with blood samples delayed for 12 hours.

Analisis Pemeriksaan Bilirubin Total Berdasarkan Variasi Waktu Paparan Cahaya Lampu Pada Spesimen

Pre-exam stage one of the most important stages in a laboratory examination which includes patient preparation, specimen reception, specimen processing, identification of specimens and preparation of reagents to be used. Specimens that are not immediately examined can cause the results of the total bilirubin examination to become unstable due to exposure to light which affects the properties of the bilirubin so that the concentration of bilirubin levels in the serum decreases. The purpose of this study was to determine the results of total bilirubin examination based on variations in exposure time to light on the specimens. This research isstudy true experimentby designrandomized pretest-posttest control groupwith 3 treatments, namely exposure to laboratory light on serum specimens for total bilirubin examination (2, 4, and 24 hours). This research was conducted in the hematology and clinical chemistry laboratories, medical laboratory technology department at the East Kalimantan Ministry of Health Polytechnic with a total sample of 40 people. The population in this study were students majoring in medical laboratory technology at the East Kalimantan Ministry of Health Polytechnic. The measurement method used in this research is methodEndPointData analysis used isOne Way ANOVA. The results obtained were clinically and statistically different in the ANOVA test which showed that exposure to light at various times of 2, 4, and 24 hours had a significant effect.

Perbandingan Glukosa Metode Carik Celup Vitamin C 500 Mg pada Penderita Diabetes Melitus Tipe 2

Vitamin C is a water-soluble vitamin and is naturally present in food. Humans cannot synthesize vitamin C, so it must be obtained from outside and food as the main source. However, taking vitamin C before a urine glucose test can cause a false positive result for some people. The purpose of this study was to analyze the comparison of the results of urine glucose levels using the strip dip method before and after consuming 500 mg vitamin C in people with type 2 diabetes mellitus. This type of research is pre-experimental with a One-group pre-post test design that assesses the causal relationship with the intervention, namely the consumption of Vitamin C in urine samples that have previously been examined for urine glucose. The population in this study were type 2 diabetes mellitus patients who were treated at the Harapan Baru Health Center and the sampling technique used purposive sampling with a total sample of 33 samples. This research was conducted at the Clinical Chemistry Laboratory of the East Kalimantan Ministry of Health Polytechnic. The results of the examination of 33 respondents showed that the percentage of results had increased by 84.5%. The normality test using the Shapiro-Wilk statistical test showed that it was significant before and after consuming vitamin C of 0.000. This shows that these values are not normally distributed. The Wilcoxon statistical test showed a significant value of 0.000 with a significance level of 0.05, i.e. 0.000 &lt;0.05, so it can be concluded that there was an increase in glucose results for urine chemistry examination by dipping method after consuming 500 mg of vitamin C in patients with type 2 diabetes mellitus.

Perbandingan Hasil Glukosa Metode Carik Celup Sebelum Dan Sesudah Mengonsumsi Vitamin C 500 Mg Pada Penderita Diabetes Melitus Tipe 2

Vitamin C is a water-soluble vitamin and is naturally present in food. Humans cannot synthesize vitamin C, so it must be obtained from outside and food as the main source. However, taking vitamin C before a urine glucose test can cause a false positive result for some people. The purpose of this study was to analyze the comparison of the results of urine glucose levels using the strip dip method before and after consuming 500 mg vitamin C in people with type 2 diabetes mellitus. This type of research is pre-experimental with a One-group pre-post test design that assesses the causal relationship with the intervention, namely the consumption of Vitamin C in urine samples that have previously been examined for urine glucose. The population in this study were type 2 diabetes mellitus patients who were treated at the Harapan Baru Health Center and the sampling technique used purposive sampling with a total sample of 33 samples. This research was conducted at the Clinical Chemistry Laboratory of the East Kalimantan Ministry of Health Polytechnic. The results of the examination of 33 respondents showed that the percentage of results had increased by 84.5%. The normality test using the Shapiro-Wilk statistical test showed that it was significant before and after consuming vitamin C of 0.000. This shows that these values are not normally distributed. The Wilcoxon statistical test showed a significant value of 0.000 with a significance level of 0.05, i.e. 0.000 &lt;0.05, so it can be concluded that there was an increase in glucose results for urine chemistry examination by dipping method after consuming 500 mg of vitamin C in patients with type 2 diabetes mellitus.

Efektivitas Daun Kelor Terhadap Kadar Kadmium Dan LDL Kolesterol Dalam Darah Sebagai Indikator Penyempitan Pembuluh Darah (Aterosklerosis) Pada Tikus Putih Yang Terpapar Asap Rokok

Tobacco consumption in Indonesia is a health epidemic that has direct or indirect toxicity due to exposure of cigarette smoke which contains harmful substances, especially cadmium metal. Cadmium’s exposure can increase the risk of coronary heart disease due to increased LDL cholesterol. One of the cadmium toxicity treatment by utilizing Moringa oleifera leaves as a natural antioxidant considering the flavonoids, saponins, ascorbic acid, carotenoids, phenolics, interquinones as cadmium chelating agents and β-sitosterol content. Therefore, it was necessary to determine the effectiveness of Moringa leaves extract in lowering blood cadmium and LDL cholesterol levels as indicators of atherosclerosis in white rats exposed to cigarettes smoke. The type of research was an experiment with quantitative analysis, conducted at the nutrition laboratory of the Faculty of Public Health Airlangga University and the clinical chemistry laboratory of Surabaya Health Polytechnic in March-July 2023. The independent variable was the doses of Moringa leaf extracts, while the dependent variables were blood cadmium and LDL cholesterol levels of white rats. The analysis of blood cadmium levels used an atomic absorption spectrophotometer and used precipitation methods by a photometer for LDL cholesterol levels. Based on statistical analysis using one way anova showed that blood cadmium levels had a significant value of &lt; 0.05, followed by post hoc tests it was found that treatment group 2 had significant differences from normal groups. Moringa leaves extract dose of 1500 mg/kgbw has been effective in lowering cadmium and LDL cholesterol levels against the risk of atherosclerosis for 14 days. Keywords : Atomic Absorption Spectrophotometry, Cadmium, LDL Cholesterol, Moringa oleifera, photometer, Rattus norvegicus

Recycling Opportunities in a High Volume Academic Clinical Chemistry Laboratory

Abstract Many sectors of industry, including the biomedical sector, have quantified waste, and created sustainability strategies to mitigate its environmental impact. One of these strategies utilizes the waste hierarchy, a model which ranks the concepts reduce, re-use and recycle in order of the most to least sustainable practice. However, to date, the clinical laboratory has seldom been evaluated for total waste production and mitigation strategies and additional public reporting of the physical amount of waste produced in these areas are lacking in the literature. In this study, we aimed to identify specific wastes produced from performing the CMP over the course of a year in our automated clinical chemistry laboratory and what proportion would be recyclable. The total in- and outpatient testing volumes as well as volumes of quality control and calibrations needed to perform the CMP at our institution were collected retrospectively from 07/14/2021 - 07/14/2022. We further identified disposables waste items such as calibrator kits, quality control kits, patient blood specimen tubes, shipping packaging and reagent wedge kits that are necessary to perform the CMP. In addition, to obtain a conservative and consistent evaluation to the total amount of waste produced from the CMP, the average weights for components of the reagent test wedge kits which includes plastic wedges, cardboard shipping boxes, and paper package inserts were calculated. These weights in conjunction with total testing volumes was used to determine the total, recyclable, and non-recyclable waste produced from these disposable items. A total of 1089.2 kg of reagent kit wastes were estimated to be produced by performing the CMP over the course of a year. Of this waste, cardboard shipping boxes and paper package inserts were determined to be recyclable (233.6 kg) and the plastic reagent wedges were determined to be non-recyclable (855.5 kg) as they were not labelled with the universally recognized recycling code, were composed of proprietary plastic material, and contained biohazardous contaminants. Overall, 21.4 % of the total specific waste weight was found to be recyclable. The CMP is a small subset of the clinical chemistry test menu that produces a considerable amount of recyclable and non-recyclable waste.

Determination of the Accuracy of Quantitative Measurement Methods in the Clinical Chemistry Laboratory at Machakos Level V Hospital, Kenya

Accuracy is the extent to which measurements are closely related to the actual values of the analyte. Accuracy is one of the key requirements in Laboratory method verification. Verification is a method of ensuring that tests are carried out per the manufacturer's specifications when tested by laboratory staff and patients at the facility. Other elements of verification include precision, linearity verified with reportable range, uncertainty of measurement, carry-over studies, reference ranges and limit of detection. This study aims to determine the accuracy of the quantitative measurement methods in the Clinical Chemistry laboratory in the month of January 2023. It also provides an alternative method for meeting accreditation requirements on accuracy by medical laboratories seeking accreditation in far-stretched laboratories where interlaboratory comparison may not be feasible. A systematic review and meta-analysis at Machakos County, Kenya. The procedure involved analysing commercially available internal quality control material five (5) times a day for eight (8) days bearing the same lot number. Roche Diagnostics, Mannheim, Germany supplied all the reagents, internal quality control materials and calibrators. Accuracy was determined using Roche Cobas® Intergra 400 Clinical Chemistry analyser to perform a comparative descriptive analysis of albumin, alanine aminotransferase (ALT), alkaline phosphatase (Alk Phos), aspartate aminotransferase (AST), chloride, creatinine, Direct Bilirubin (D. Bil), Gamma-glutamyl transferase (GGT), potassium, sodium, total bilirubin, total protein, and urea. The study followed guidelines issued by the Clinical Laboratory Improvements Amendment 1988 (CLIA) and Clinical Laboratory Standards Institute (2014). Data analysis was carried out using Excel Windows 10 MS Office 2021. Mean, standard deviation (SD), Z-score, bias %, coefficient of variation (CV) %, and total error allowable (Tea) were calculated from the results of measurement of the analytes. All the analytes achieved a mean which fell within the manufacturer verification interval and hence passed. The bias % score for the analytes was as follows 5 analytes level (19.2%) scored 0 - ±1, 10 analytes level (38.5%) scored ±1.1 - ±2, 7 analytes level (26.9%) ±2.1 - ±3 and 4 analytes level (15.4%) scored above ±3. All analytes were found to have an excellent Z-score performance between 0 to ± 1.96. The total error allowable was found to fall within CLIA and CLSI specifications limits except for chloride PCC1/ Normal control which failed at 5.82% (CLIA target being ± 5%). Analytes' mean was expected to fall within the given manufacturer's mean. The bias % for the analytes which was at zero or near ± zero was considered an excellent score the further away the score was, the poorer the performance. The Z-score was also calculated to establish how far the observed mean fell from the target mean. All analytes were found to have an excellent Z-score performance between 0 to ± 1.96. A Z-score of ± 1.96 to ± 2.57 indicates good performance while a Z-score of over ± 2.58 indicates failed performance. These good results are attributable to the fact that analysis was carried out within a very short duration by the same person, on the state-of-the-art instrument, in a well-controlled environment hence no room for analytical variation. Chloride being an electrolyte failed since it is physiologically controlled in a strict and narrow range.

The Strange Case of Orotic Acid: The Different Expression of Pyrimidines Biosynthesis in Healthy Males and Females.

Orotic acid (OA) is an intermediate metabolite of pyrimidine nucleotide biosynthesis and represents a minor diet constituent. The measurement of urinary orotic acid is useful in confirming the diagnosis of hereditary metabolic diseases. Moreover, it could be of interest to know how the physiological concentration of this metabolite changes in relation to different conditions of clinical normality. The purpose of this study was to determine the orotic acid concentration in the urine of healthy patients, to observe normal oroticuria and to evaluate if the expression of pyrimidine intermediate biosynthesis differs between healthy males and females. The orotic acid concentration in urine was performed via the ICH M10-validated analytical method. Unexpectedly, females showed a greater oroticuria than males in pediatric age (0-10); conversely, we did not find significant differences until 70 years of age. The LC-MS/MS method was suitable for use in the differential diagnosis of hereditary metabolic disease and metabolic monitoring of anticancer drug-induced toxicity. The analytical protocol was found to be rapid and ideal, and was used in the routine analysis of a clinical chemistry laboratory. The biochemical aspects related to the expression of pyrimidine biosynthesis should be further investigated in light of the obtained results.