Clinical Biochemistry Laboratory Research Articles

A study of adequacy of completion of clinical biochemistry laboratory request forms

Background: Laboratory request forms are essential communication tool between the clinicians and laboratory personnel. In view of the meagerness of studies exploring request forms as a part of preanalytical errors, we planned to evaluate the request forms received at the clinical biochemistry laboratory. Objective: The aim of this study was to evaluate the adequacy of the details of laboratory request forms that had been submitted to biochemistry department. Materials and Methods: This lab audit was carried out at the clinical biochemistry laboratory of a tertiary care teaching hospital. The forms Laboratory request forms were segregated to evaluate the extent of completion of each form, completion of the columns, legibility of the clinician`s handwriting. The results were expressed in percentages. Results: A total of three thousand and fifty (3050) request forms were analyzed. The location of the patient and referring department were missing in 35.3% and 29.4% of the forms respectively. Provisional diagnosis was provided only in 53.3% of the request forms. Conclusion: This study concludes that the location of the patient, probable diagnosis, medical officer`s signature had not been entered in the request forms. As laboratory plays a crucial role in the patient diagnosis, incomplete data in the request form might significantly affects the lab service which in turn affects the patient’s health care system. The standard of filling of laboratory request forms needs to improve to provide a high quality lab service.

Do serum lipid hydroperoxide and free sulfhydryl use for biochemical markers of migraine?

Aim: In this study we aimed to evaluate the serum Lipid Hydroperoxide (LOOH) and Free Sulphydryl (-SH) levels of Common Migraine Patients compared to healthy controls. Material and methods: This study was conducted as a prospective case-control study. Fourty Common Migraine Patients according to the diagnostic criteria of the International Headache Society and fifty two healthy volunteers as controls were included to the study. The participants were informed of the content and conduct of the study and informed consent forms were obtained. Serum samples were collected and were centrifuged. Serum Lipid Hydroperoxide and Free Sulfhydryl levels were studied in the same Clinical Biochemistry Laboratory at the same time. Results: Serum SH levels were statistically decreased in Common Migraine Patients group compared to control group (P < 0.005). There was no statistically significant difference in Serum LOOH between patients and the control group (P > 0.005). There was a negative correlation between SH and LOOH serum levels. Conclusion: The data of this study demonstrate decreased serum SH level in Common Migraine. Based on these findings, we suggest that these parameters may be used as biochemical markers for Common Migraine.

Analysis of Laboratory Critical value Reporting Pattern at clinical biochemistry laboratory of Tertiary health care Center

Objectives: Objective of the study is to analyze critical value reporting data to find frequency of critical reporting, distribution of critical values across reportable range and across hospital segments and reasons for failure in critical reporting. Material & Method: The critical value reporting data for various analysts were collected from LIS for 1 year. The data were analyzed in computer spreadsheets. Result & Discussion: Of 548786 test results analyzed, about 10% results were critical. Total Billirubin (20.14 %), Indirect Billirubin (18 %), Glucose (18%) and Sodium (13.6 %),Potassium (11.8%) contributed most to the critical values. 29% of urea, 13.29 % of Glucose ,15.37% of Indirect Billirubin, 13.71% of Sodium, 13.29% of Glucose & 11.6 % of total analyzed potassium were critical. On a per test basis, inpatient tests were 3.6 times more likely to result in a critical callback than outpatient tests. The number of critical values per year per bed was 176.34 for ICU beds and 29.36 for non-ICU beds and 5.0 for Emergency Department. Conclusion: The high proportion of reported critical value of urea is due to practice of reflex testing in the laboratory whenever Creatinine is in abnormal range. The high proportion of reported critical value of Indirect Billirubin is due to present of PICU, NICU in Hospital. Major reasons for failure of notification of critical alert are incomplete detail on request form, transfer of patient to Ward or ICU, phone is engaged or phone not picked up by care giver.

Rapid, easy analysis of urinary vanillylmandelic acid for diagnostic testing of pheochromocytoma by liquid chromatography tandem mass spectrometry.

Vanillylmandelic acid (VMA), as one of the most important catecholamine metabolites, is commonly used to aid in diagnosis of pheochromocytoma. This study develops a rapid and simple high-throughput LC-MS/MS method for the measurement of urinary VMA. Without sample pretreatment, the urine specimens were mixed with internal standard (IS) solution for direct analysis by LC-MS/MS in two minutes. VMA and VMA-d3 were detected in the multiple-reaction monitoring mode using the specific transitions m/z 197.0→137.0 and 200.0→140.0, respectively. This method was validated for consistent linearity from 1.0 to 250.0μM with CVs≤3.12%, excellent recovery, good stability and low carryover. The lowest limit of quantification (LLOQ) was 0.125μmol/L for VMA with CV of 14.1%, and the lower limit of detection (LOD) was 0.025μmol/L. Intra-assay and inter-assay imprecision values (CVs) for VMA were all below 2.11%. Dilution linearity was investigated with a satisfied mean accordance of 105%. Method comparison of LC-MS/MS and microcolumn chromatography in our lab was performed and the reference interval was established in agreement with that of the Mayo Clinic. All these results demonstrate that this validated LC-MS/MS approach shows improved accuracy and reproducibility compared with microcolumn chromatography. The low sample volume, simplicity, rapidity, and robustness of the method make it suitable for use as a high-throughput assay in routine clinical biochemistry laboratories.

Determination of sub-groups in reference interval calculations and an application

Abstract Objective: The main objective of this study is to determine the methods used for dividing reference data into sub-groups and propose a new solution. Therefore, the newly proposed method is used to determine age sub-groups while calculating the reference interval of AST variable. Methods: The data of this study are composed of the registered patients who applied only once to the polyclinics at the Health Research and Application Hospital, Clinical Bio-Chemistry Laboratory of Mersin University. The main variables selected for the study are sex, age and aspartate transaminase (AST). MARS 2.0 package software was used for the statistical analysis. Harris&amp;Boyd method was used for sex and age while the MARS method was used for the determination of age sub-groups. Results: According to the Harris&amp;Boyd method, it was concluded that it is not necessary to create sub-groups for sex and age variables. Age sub-groups are determined with the MARS method by taking into account the correlations between AST variables and age. Age sub-groups are calculated as 5-9, 10-18 and 19+. Correlation between the age and AST variable is investigated for these sub-groups. It is obtained that the correlation is statistically not significant for the 5-9 age group (p=0.3189), significant for the 10-18 age group (p&lt;0.001) and significant for 19 and above (p&lt;0.001). Conclusion: The selection of transformation and outlier value elimination method and especially determination criteria for separation of sub-groups are made according to researcher’s subjective desicions in the application of many studies. Because of this reason, MARS can be used as an alternative and objective method for determining subgroups. In addition, results of MARS method being parallel with the findings of the producing company supported the usage of this method for determination of sub-groups.

Biochemical consequences of bariatric surgery for extreme clinical obesity.

Obesity, defined as a body mass index over 30 kg/m(2) for adults, poses a major healthcare challenge with important economic, personal and social consequences. Although public health measures, lifestyle change and pharmacological therapies have an important role in the management of obesity, patients with established morbid obesity (body mass index over 40 kg/m(2)) may also require bariatric surgery. Bariatric or metabolic surgery is associated with effective and enduring weight loss but is also known to improve glucose homeostasis, blood pressure and dyslipidaemia. Patients who have bariatric surgery need lifelong clinical follow-up to identify and prevent nutritional deficiencies and other complications. Clinical biochemistry laboratories have an important role in the nutritional assessment of obese patients and in the identification of complications following bariatric surgery. The aim of this article is to review the different bariatric procedures available and to summarize their complications, especially nutrient deficiencies and those of particular relevance to clinical biochemistry laboratories.

English

Thin layer chromatography is a neglected test and is about to become obsolete from the clinical biochemistry laboratories. In this context, the aim of the present study is to determine the reducing sugar that is present in the urine samples sent to the lab as a routine investigation in a pediatric hospital setup. METHODS: A retrospective study of 383 sick children of neonatal to pediatric age group were selected during the previous one year period and their reports of Benedicts test for urine reducing substances, Multistix dipstick for Glucose and corresponding thin layer chromatography study were analysed. MS excel sheet used for statistical analysis and charts.

External quality assessment in clinical biochemistry laboratories: pilot study in 11 laboratories of Lomé (Togo)

This study aims to evaluate the performance of a few biochemistry analysis and make recommendations to the place of the stakeholders. It is a cross-sectional study conducted between the October 1(st), 2012 and the July 31, 2013 bearing on the results of 5 common examinations of clinical biochemistry, provided by 11 laboratories volunteers opening in the public and private sectors. These laboratories have analysed during the 3 cycles, 2 levels (medium and high) of serum concentration of urea, glucose, creatinine and serum aminotransferases. The performance of laboratories have been determined from the acceptable limits corresponding to the limits of total errors, defined by the French Society of Clinical Biology (SFBC). A system of internal quality control is implemented by all laboratories and 45% of them participated in international programs of external quality assessment (EQA). The rate of acceptable results for the entire study was of 69%. There was a significant difference (p<0.002) between the performance of the group of laboratories engaged in a quality approach and the group with default implementation of the quality approach. Also a significant difference was observed between the laboratories of the central level and those of the peripheral level of our health system (p<0.047). The performance of the results provided by the laboratories remains relatively unsatisfactory. It is important that the Ministry of Health put in place a national program of EQA with mandatory participation.

Total folate and 5-methyltetrahydrofolate in the cerebrospinal fluid of children: correlation and reference values.

Cerebral folate deficiency (CFD) may be underdiagnosed, as it manifests with various non-specific neurological symptoms. The diagnosis of CFD requires a determination of 5-methyltetrahydrofolate (5MTHF) in the cerebrospinal fluid (CSF), which is available in a limited number of specialized laboratories. In clinical biochemistry laboratories, total folate (TF) determination in serum or plasma is routinely performed by automated analyzers. The aim of this study is to determine whether the automated assay of CSF TF is a helpful screening tool for CFD. We analyzed CSF samples collected from 73 pediatric patients. We measured CSF TF, serum TF, and CSF 5MTHF in 73, 70, and 48 patients, respectively. The assay of 5MTHF was conducted by a newly developed system utilizing liquid chromatography-tandem mass spectrometry (LC-MS/MS). We investigated the correlation between TF and 5MTHF in the CSF. There was a strong positive correlation between CSF TF and 5MTHF (ρ=0.930, p<0.0001, n=48). Age was negatively correlated with CSF TF (ρ=-0.557, p<0.0001, n=51), serum TF (ρ=-0.457, p=0.0008, n=51), and CSF 5MTHF (ρ=-0.387, p=0.0263, n=33), but not with the CSF/serum TF ratio. The automated assay of CSF TF is helpful to estimate CSF 5MTHF. The CSF TF assay may have a significant impact on the early diagnosis of CFD, because clinicians have better access to it than the 5MTHF assay.

Evaluation of analytical errors in a clinical chemistry laboratory: a 3 year experience.

Background:Proficient laboratory service is the cornerstone of modern healthcare systems and has an impact on over 70% of medical decisions on admission, discharge, and medications. In recent years, there is an increasing awareness of the importance of errors in laboratory practice and their possible negative impact on patient outcomes.Aim:We retrospectively analyzed data spanning a period of 3 years on analytical errors observed in our laboratory. The data covered errors over the whole testing cycle including pre-, intra-, and post-analytical phases and discussed strategies pertinent to our settings to minimize their occurrence.Materials and Methods:We described the occurrence of pre-analytical, analytical and post-analytical errors observed at the Komfo Anokye Teaching Hospital clinical biochemistry laboratory during a 3-year period from January, 2010 to December, 2012. Data were analyzed with Graph Pad Prism 5(GraphPad Software Inc. CA USA).Results:A total of 589,510 tests was performed on 188,503 outpatients and hospitalized patients. The overall error rate for the 3 years was 4.7% (27,520/58,950). Pre-analytical, analytical and post-analytical errors contributed 3.7% (2210/58,950), 0.1% (108/58,950), and 0.9% (512/58,950), respectively. The number of tests reduced significantly over the 3-year period, but this did not correspond with a reduction in the overall error rate (P = 0.90) along with the years.Conclusion:Analytical errors are embedded within our total process setup especially pre-analytical and post-analytical phases. Strategic measures including quality assessment programs for staff involved in pre-analytical processes should be intensified.

Validation of biochemical testing of fluid samples

Clinical Biochemistry laboratories occasionally receive requests for the analysis of various analytes in body fluids other than serum, plasma or urine. The clinical need to perform this testing can be diverse, but is most often to detect the specific organ involvement or injury that has led to the fluid accumulation. Whilst assays for the measurement of most analytes requested are readily available, strict compliance to laboratory regulations could rule out the performance of these tests on body fluids on the grounds that: 1. Matrix effects from proteins or other constituents could interfere with accurate measurement of those analytes. 2. Assay manufacturers usually do not provide assay performance claims for fluids other than serum, plasma or urine. 3. Clinical laboratories lack the resources to undertake extensive method validation for all fluid types. 4. Clinical laboratories lack established reference intervals for these analytes in various fluid types. Nevertheless, clinicians can find value in the results of fluid testing in direct comparison with concurrent results in serum or plasma to establish whether the fluid has a relatively high concentration or a concentration similar to that in serum or plasma. A high concentration may suggest direct organ involvement in the accumulation of the fluid. This presentation aims to summarise the issues related to fluid testing and report on national activities aimed at providing guidance to clinical laboratories in various aspects of biochemical fluid testing.

Are tubes containing sodium fluoride still needed for the measurement of blood glucose in hospital laboratory practice?

To compare glucose values obtained using sodium flouride (NaF) tubes and serum separation tubes (SST) in a tertiary care hospital laboratory setting. This study was conducted at the Clinical Biochemistry Laboratory, Royal Hospital, Oman. During the study period (1 September-30 November 2013), 50 pairs (one NaF tube and one SST) of patient's blood specimens were randomly collected. Following separation of plasma (NaF tubes) and serum (SST), glucose concentrations were measured by hexokinase assay using the Architect c8000. Fifteen pairs of these tubes were kept in the refrigerator at 4°C and plasma/serum glucose concentrations were measured daily up to seven days after collection. Comparing plasma (NaF) and serum (SST) results of glucose values (n=50) showed an average difference of 0.00mmol/L (range -0.60 to +0.60mmol/L). Bland Altman analysis gave a non-significant constant bias of 0.10 ±0.195mmol/L (bias ±SD). Pearson correlation between plasma (NaF) and serum (SST) glucose concentrations revealed a significant correlation approaching unity with r(2)= 0.9991. No significant differences in glucose values were noted for both plasma and serum in 15 pairs of NaF and SST tubes when analyzed seven days following refrigeration. Hemolysis was observed in five (10%) NaF tubes compared with two (4%) SST. There is no difference in glucose values collected from plasma NaF tubes or serum SST, and so SST can be used in hospital laboratory settings as there are practical advantages, including cost-effectiveness and reduction in blood volume drawn when utilizing these tubes for glucose and other tests from a single blood collection tube.

A study of pre-analytical errors in a hospital based clinical biochemistry laboratory and formulation of measures for correction

A prospective observational study was done in the Central Clinical Laboratory of Gauhati Medical College & Hospital for a period of 2 months from 1 st March to 30 th April 2014. The objective of the study was to evaluate the pre-analytical phase of laboratory testing in a Clinical Biochemistry Laboratory to detect the different errors which occurred in the preanalytical phase and calculate their percentage and to determine in which step the error occurred so that corrective measures can be formulated to avoid such errors. All the samples and their accompanying laboratory request forms were screened for pre-analytical errors and the daily errors and their types recorded in Problem Notification Logbook. The data collected was analyzed and the entire process of sample collection and transport was evaluated to formulate corrective measures to prevent these errors from occurring. The total number of samples received in 2 months was 23,680. Out of this OPD samples were 11,414 and Indoor samples were 12,266.Of the 12,266 laboratory request forms which were screened 12,106, forms were incomplete i.e. only 160 forms carried all the required information. Out of the total 23,680 sample tubes screened preanalytical errors were observed in 6.61% of Indoor samples and 3.69% of OPD samples. Hemolysed sample was the most commonly observed preanalytical error both in OPD and Indoor samples. Hemolysis was observed in 4.25% of Indoor samples and in 3.55% of OPD samples. Insufficient sample volume was observed in 1.74% of Indoor and .026% of OPD samples. Preanalytical error was observed in 5.20% of samples during the study period. Of this 3.91% of samples received were hemolysed and were rejected .Corrective measures have to be taken to reduce the percentage of rejected samples.

Quality of Control of Clinical-Biochemical Laboratories – Serbian Case

Quality of Control of Clinical-Biochemical Laboratories – Serbian Case

Quality of Control of Clinical-Biochemical Laboratories – Serbian Case

In the last 20 years in medical laboratories, numerous activities regarding quality and accreditation system were taken. Approach to this problem in European countries is different, so the task of the Accreditation Work Group of the Confederation of European societies for clinical chemistry (EC 4) to help the efforts to harmonize this issue. External quality control in clinical-chemical laboratories imposed the need for the implementation of quality management system. »Good laboratory practice« and its principles were adopted by nominated bodies, both international and national. In the beginning, the standard ISO 9001 was applied for certification and for accreditation EN 45001 and ISO Guide 25, which are prepared for testing and calibration laboratories. Standard ISO 17025 is the successor of the previous documents and for now it is a reference for mentioned laboratories. Accreditation Work Group of the Confederation of European societies for clinical chemistry (EC 4) made an amendment of the requirements for medical laboratories, which this standard describes. Standard draft ISO 15189 was adopted on February 2003 as a final version with requirements for medical laboratories.

Quality of Control of Clinical-Biochemical Laboratories – Serbian Case

In the last 20 years in medical laboratories, numerous activities regarding quality and accreditation system were taken. Approach to this problem in European countries is different, so the task of the Accreditation Work Group of the Confederation of European societies for clinical chemistry (EC 4) to help the efforts to harmonize this issue. External quality control in clinical-chemical laboratories imposed the need for the implementation of quality management system. »Good laboratory practice« and its principles were adopted by nominated bodies, both international and national. In the beginning, the standard ISO 9001 was applied for certification and for accreditation EN 45001 and ISO Guide 25, which are prepared for testing and calibration laboratories. Standard ISO 17025 is the successor of the previous documents and for now it is a reference for mentioned laboratories. Accreditation Work Group of the Confederation of European societies for clinical chemistry (EC 4) made an amendment of the requirements for medical laboratories, which this standard describes. Standard draft ISO 15189 was adopted on February 2003 as a final version with requirements for medical laboratories.

Application of Indices Cp and Cpk to Improve Quality Control Capability in Clinical Biochemistry Laboratories

The traditional criteria for acceptability of analytic quality may not be objective in clinical laboratories. To establish quality control procedures intended to enhance Westgard multi-rules for improving the quality of clinical biochemistry tests, we applied the Cp and Cpk quality-control indices to monitor tolerance fitting and systematic variation of clinical biochemistry test results. Daily quality-control data of a large Taiwanese hospital in 2009 were analyzed. The test items were selected based on an Olympus biochemistry machine and included serum albumin, aspartate aminotransferase, cholesterol, glucose and potassium levels. Cp and Cpk values were calculated for normal and abnormal levels, respectively. The tolerance range was estimated with data from 50 laboratories using the same instruments and reagents. The results showed a monthly trend of variation for the five items under investigation. The index values of glucose were lower than those of the other items, and their values were usually <2. In contrast to the Cp value for cholesterol, Cpk of cholesterol was lower than 2, indicating a systematic error that should be further investigated. This finding suggests a degree of variation or failure to meet specifications that should be corrected. The study indicated that Cp and Cpk could be applied not only for monitoring variations in quality control, but also for revealing inter-laboratory qualitycontrol capability differences.

Effect of Hemolysis on Plasma Cardiac Troponin Levels at Clinically Relevant Concentrations: An Experimental Study

Hemolysis is one of the most commonly encountered pre-analytical sources of interference in the Clinical Biochemistry laboratory. Hemolysis is known to cause a variable interference in both cardiac troponin I (cTnI) and troponin T (cTnT) assays. Each laboratory should determine and publicize these effects. In this experimental study we determined the effect of in-vitro sample hemolysis on both types of cardiac troponin assays and whether the effect was clinically significant

Validation of Method Performance of pH, PCO2, PO2, Na(+), K(+) of Cobas b121 ABG Analyser.

The introduction of a new method or new analyser is a common occurrence in clinical biochemistry laboratory. Blood gas measurements and electrolytes are often performed in Point-of-Care (POC) settings. When a new POC analyser is obtained, the performance of the analyser should be evaluated by comparison to the measurements with the reference analyser in the laboratory. Evaluation of method performance of pH, PCO2, PO2, Na(+), K(+) of cobas b121 ABG analyser. The evaluation of method performance of pH, PO2, PCO2, Na(+), K(+) of cobas b121 ABG analyser was done by comparing the results of 50 patient samples run on cobas b121 with the results obtained from Rapid lab values (reference analyser). Correlation coefficient was calculated from the results obtained from both the analysers. Precision was calculated by running biorad ABG control samples. The correlation coefficient values obtained for parameters were close to 1.0 indicating good correlation. The CV obtained for all the parameters were less than 5 indicating good precision. The new ABG analyser, Cobas b121 correlated well with the reference ABG analyser (Rapid Lab) and could be used to run on patient samples.

Serum thyroid hormone reference intervals in the apparently healthy individuals of Zhengzhou area of China.

This study aimed to establish reference intervals for serum thyroid hormones [serum thyroid-stimulating hormone (TSH), triiodothyronine (TT3), thyroxine (TT4), free triiodothyronine (FT3), and free thyroxine (FT4)] in apparently healthy individuals living in Zhengzhou. According to the requirement for laboratory support for the diagnosis and monitoring of thyroid diseases in the National Academy of Clinical Biochemistry (NACB) laboratory medicine practice guidelines, a total of 211 apparently healthy individuals were enrolled (94 men, 117 women, 23-77 years old) from Zhengzhou for measurement of serum levels of TSH, TT3, TT4, FT3, and FT4 by using the Siemens ADVIA Centaur XP analyzer. All markers were analyzed across gender- and age-specific groups by using the t-test and ANOVA. The reference intervals of all markers were determined by P2.5-P97.5. We detected gender-associated statistical significances for TT3, TT4, FT3, and FT4 (t=3.299, 2.141, 5.868, 5.358; P<0.05), but not for TSH (t=-1.776, P>0.05). Correlation analysis showed that all markers were negatively correlated with age (P>0.05). The new reference intervals for TT3, TT4, FT3, FT4, and TSH were established: 0.76-1.38 ng/mL, 5.96-11.27 μg/dL, 3.88-5.59 pM, 11.69-18.84 pM, 0.89-5.93 μIU/mL, respectively. In conclusion, we added a new database of reference intervals of the serum thyroid hormones for the Chinese adult population.