Quality Control Sera Research Articles

A-095 A New CO2 Assay with Concentrated Reagent Having Superior Onboard Stability on Mindray BS-2800M Analyzer

Abstract Background Measurement of total content of CO2 in serum or plasma can be used to assist in the diagnosis of various acid-base disorders. There are small amounts (about 0.04%) CO2 in the earth’s atmosphere, or more in an enclosed clinical laboratory space. The environmental CO2 could be dissolved into the CO2 reagent continuously, in particular at lowered temperature when it is opened and stored on the system, which leads an impact on CO2 assay performance. Presently, competitors mainly use additional inserts or with small opening of the reagent container to reduce the contact with air from reagent, to improve its onboard stability. Here, we designed a new CO2 assay by optimizing the reagent formulation with a new protection mechanism to reduce the amount of CO2 absorption to the reagent and improved its onboard stability. This study evaluated performances of the new CO2 assay on Mindray BS-2800M analyzer. Methods Mindray CO2 assay with concentrated reagent is based on PEPC (Phosphoenolpyruvate Carboxylase) enzymatic method. It is designed with an innovative mechanism of reagent formulations with a protective layer of chemical(s) on top of the reagent that prevents CO2 from entering the reagent and reduced its impact to its on-board stability. The onboard stability was conducted with a constant reagent consumption mode to simulate as it in clinical lab use. The onboard study used two levels of Quality Control materials and serum pools. According to CLSI protocols, the following assay performances were evaluated: onboard stability, precision, method comparison, linearity, and interference. Results On Mindray BS-2800M analyzer, Mindray CO2 assay demonstrated an excellent onboard stability. With uncapped reagent on the system, the stability is for 21 days without recalibration, with less than ± 5% deviation from day zero. In parallel onboard stability studies, with Roche CO2 reagent on Cobas c701 system, the relative deviation from day zero was found to be within ±10%; and other three manufacturers` results with deviation exceeded ±10% vs. day zero in 7 days. The linearity of Mindray CO2 assay was determined as from 2.0 to 50.0 mmol/L. Our CO2 assay correlated well with Roche CO2 on Cobas c701 (Mindray = 1.0032 * Roche - 0.0186, r≥0.99). The repeatability and with-lab CVs were ranged from 0.64% to 3.41%, respectively. There was no significant interference (<±10%), at CO2 concentration of 15 mmol/L with bilirubin up to 60 mg/dL,hemolysate up to 800 mg/dL, Intralipid up to 1000 mg/dL, triglycerides up to 1000 mg/dL. Conclusions On Mindray BS-2800M analyzer, the new CO2 assay demonstrated a good ability against environmental CO2 inference in 21 days of onboard time. The new CO2 assay also shown good performances in precision, correlation (accuracy) and anti-interference from endogenous substances. Therefore, we conclude that the new Mindray CO2 assay is suitable for routine clinical laboratory use.

Application of the adaptive Monte Carlo method for uncertainty evaluation in the determination of total testosterone in human serum by triple isotope dilution mass spectrometry

The measurement uncertainty is a crucial quantitative parameter for assessing the reliability of the result. The study aimed to propose a new budget for uncertainty evaluation of a reference measurement procedure for the determination of total testosterone in human serum. The adaptive Monte Carlo method (aMCM) was used for the propagation of probability distributions assigned to various input quantities to determine the uncertainty of the testosterone concentration. The basic principles of the propagation and the statistical analysis were described based on the experimental results of the quality control serum sample. The analysis of the number of Monte Carlo trials was discussed. The procedure of validation of the GUM uncertainty framework using the aMCM was also provided. The number of Monte Carlo trials was 2.974 × 106 when the results had stabilized. The total testosterone concentration was 16.02 nmol/L, and the standard uncertainty was 0.30 nmol/L. The coverage interval at coverage probability of 95% was 15.45 to 16.62 nmol/L, while the probability distribution for testosterone concentration was approximately described by a Gaussian distribution. The validation of results was not passed as the expanded uncertainty result obtained by the aMCM was slightly lower, about 7%, than that by the GUM uncertainty framework with consistent results of the concentration.Graphical

Improvement of laboratory testing services by implementation of quality assurance scheme

Introduction: The National AIDS Control Organization (NACO), Government of India and the Uttar Pradesh State AIDS Control Society (UPSACS) established the State Referral Laboratory (SRL) in the Department of Microbiology, Motilal Nehru Medical College, Prayagraj for HIV testing and monitoring of linked HIV Counselling and Testing Services (HCTS) in Uttar Pradesh.Methods: This is a retrospective study conducted from 2008 to 2021. In this evaluation period 10144 serum samples (9580 HIV negative, 555 HIV positive and 9 discordant) were received for retesting at SRL. The Quality Control serum samples received from testing sites consisted of 5% negative and 20% positive from all tested samples collected in the first seven days in the External Quality Assurance Scheme (EQAS) quarter month i.e. January, April, July and October. All samples were tested using rapid diagnostic kits procured by NACO/UPSACS with NACO testing strategy. All linked centres with SRL received 4 coded serum samples for proficiency testing (PT) which were tested similarly.Results: Of 10144 serum samples, 99.92% reported correct results and 0.08% reported discrepancy due to various issues. Similarly in the proficiency testing programme, of 4072 samples tested between 2010 to 2021 by testing sites, 4061 (99.07%) reported concordant results and the remaining14 (0.34%) samples reported indeterminate results. Of the 4072 samples, 14 shows discordant results by three different rapid tests based on different principles. Hands on training were provided for technicians who reported indeterminate results in PT or retesting.Conclusion: The tremendous increase in quality testing at peripheral centrally linked centres increase the reliability of HIV diagnosis at ground level. The study also concluded that continuous monitoring and mentoring of technicians of the diagnostic laboratories under EQAS improves their quality for HIV diagnosis.

Evaluation of the performance of an handheld device for measuring cholinesterase activity, in order to use in cases of organophosphate poisoning

Cholinesterase activity monitoring during the organophosphorus pesticides poisoning is still a challenge in the remote areas. The objective of this study was to evaluate the performance of the Test-mate Model 400 EQM® for the determination of cholinesterase. This is a cross-sectional analytical study conducted with two different levels of quality control sera (QCs) and 40 sera of different cholinesterase concentrations from patients samples. The coefficient of variation obtained for repeatability was compared to the supplier's values. Spearman's coefficient and kappa coefficient (ĸ) were used to examine correlation and assess agreement between measurements obtained with the handheld device and the INDIKO analyzer, used as a reference test. For repeatability of EQM Test-mate ChE®, coefficients of variation was 5.5% and 6% for the normal and pathological control sera respectively, that is lower than 7.5% as recommended by the supplier. A Spearman correlation coefficient of r=0.7451 (p<0.0001) was obtained and a good agreement between the measurements ( ĸ=0.7253 (95%CI: 0.655- 0.841)). This handheld device is repeatable and showed a good correlation and agreement with the INDIKO® analyzer. It would therefore be suitable for determining cholinesterase activity in remote areas in case of organophosphate poisoning.

B-379 Analytical Performance of Two Tumor Marker Immunoassays on the Atellica CI 1900 Analyzer

Abstract Background The Atellica® CI 1900 Analyzer is an automated, mid-throughput, integrated chemistry and immunoassay analyzer utilizing both Atellica CH and Atellica IM assays. This study was designed to evaluate the analytical performance of the Atellica IM Carcinoembryonic Antigen (CEA) and Alpha Fetoprotein (AFP) assays* on the Atellica CI 1900 Analyzer. Methods The Atellica CI 1900 CEA and AFP assays use the same reagents and calibrators as the comparable Atellica IM assays. Precision and method comparison (MC) were used as performance indicators for the Atellica CI 1900 Analyzer. Precision studies were performed according to CLSI EP05-A3 using quality control, native, and contrived human serum samples. One aliquot of each sample pool was tested in duplicate in two runs per day ≥2 h apart on each analyzer for ≥20 days. MC studies were performed according to CLSI EP09-A3. Individual native and contrived human serum samples were analyzed using the Atellica IM assays on both the Atellica IM and Atellica CI 1900 Analyzers. Results Representative precision and MC results observed for each assay across indicated sample ranges are listed in the table. Slopes determined by the Deming linear regression model were approximately equal to 1. Conclusion Evaluation of the CEA and AFP assays using the Atellica CI 1900 Analyzer demonstrated good precision and equivalent performance compared to the same assays on the Atellica IM Analyzer. *The products/features mentioned here are not commercially available in all countries. Their future availability cannot be guaranteed.

Efficacy of In-House Quality Control Material Compared to Commercially Available Quality Control for Thyroid Hormone

Laboratory results in clinical laboratories are being generated by automated analyzers. The constant use of commercialcontrol materials is not economically feasible for many countries because of the non-availability or high cost of those materials.Therefore, the preparation of in-house quality control serum will be cost-effective for use in the laboratory. The commercialquality control for immunoassay is costlier and as per NABL 112 criteria, at least two levels of quality control should be run everyday for a laboratory with a large sample load. To overcome this problem our study aims to evaluate the efficacy of in-housepooled serum quality control in comparison with commercial internal quality control samples in thyroid hormone tests. Weprepared in-house quality control from leftover samples of subjects tested for thyroid profile after being screened for HIV, HCV,and HBsAg by pooling them together in a glass jar serum and kept in a deep freezer at -20ºC. Pooled serum was aliquot into 20vials each containing 500 μl. Every day along with commercial internal QC, one aliquot of pooled serum was analyzed for thirtydays for the following parameters: TSH, FT3, FT4. After getting thirty values for each parameter, mean, standard deviation, andcoefficient of variation were calculated for both IQC commercial sample and pooled serum sample.: In-house prepared qualitycontrol material performed as well as commercial quality control for thyroid profile. Therefore, prepared in-house quality controlcan be a good substitute for commercial quality control for thyroid profile.

Development of an indirect ELISA against African swine fever virus using two recombinant antigens, partial p22 and p30

African swine fever (ASF) is a highly fatal viral disease affecting pigs. It is caused by the ASF virus (ASFV), and causes serious economic losses to the swine industry worldwide, including in Korea. Commercially available enzyme-linked immunosorbent assay (ELISA) kits for detecting anti-ASFV antibodies are used for the diagnosis and surveillance of ASF. In this study, an ELISA was developed to detect anti-ASFV antibodies using two recombinant proteins, p22 and p30, from genotype II ASFV. Recombinant transmembrane domain-deleted p22 (p22∆TM) and p30 were expressed in E.coli vector system pET32a and mixed for use as antigens in indirect ELISA. The p22∆TM/p30-based indirect ELISA was validated using 31 sera from genotype I ASFV-infected pigs and 1133 sera from uninfected pigs. Area under the curve of this test was 0.999 [95 % concentration interval 0.992–1.000], and sensitivity and specificity were 93.5 % and 99.8 %, respectively. The between run coefficient of variation for internal quality control serum was 6.61 %. In the seroconversion analysis, the p22∆TM/p30-based indirect ELISA showed equal or better ability to detect antibodies in pigs experimentally challenged with ASFV p72 genotypes I and II (p < 0.05). In conclusion, the p22∆TM/p30-based indirect ELISA is a reliable diagnostic method for detecting anti-ASFV antibodies.

Development of a Blocking Enzyme-Linked Immunosorbent Assay for Detection of Antibodies against African Swine Fever Virus.

The incursion of African swine fever virus (ASFV) into Eurasia presents a threat to the world’s swine industry. Highly sensitive and specific diagnostic assays are urgently needed for rapid detection during an outbreak, post-outbreak investigation, and disease surveillance. In this study, a highly specific and repeatable blocking ELISA (bELISA) was developed using a recombinant p30 protein as the antigen combined with biotinylated mAb against p30 as the detection antibody. Initial test validation included sera from 810 uninfected animals and 106 animals experimentally inoculated with ASFV or recombinant alphavirus/adenovirus expressing p30. Receiver operating characteristic (ROC) analysis of the data calculated an optimal percentage of inhibition (PI) cutoff value of 45.92%, giving a diagnostic sensitivity of 98.11% and diagnostic specificity of 99.42%. The coefficient of variation of an internal quality control serum was 6.81% for between runs, 6.71% for within run, and 6.14% for within plate. A time course study of infected pigs showed that bELISA was able to detect seroconversion as early as 7 days post-inoculation. Taken together, these results demonstrate that bELISA can be used as an alternative serological test for detecting ASFV infection.

Development of NCOVID-19 Colloidal Gold Immunochromatographic Test Strip

&lt;div&gt;&lt;p&gt;Purpose: To establish a fast, simple and accurate method and immunoassay test card for the detection of new coronavirus (nCOVID-19) antigen. Methods: In this study, colloidal gold immunochromatography technology was used to detect nCOVID-19 virus antigens through the sandwich method. At the same time, the preparation plan of colloidal gold was improved, and the application of rapid immune-diagnosis technology in other fields was developed. In this study, purified recombinant nCOVID-19 nucleocapsid protein is used as the antigen to prepare murine monoclonal antibodies. The BN02 antibody produced by the mouse is used as the detection antibody to couple with colloidal gold, forming a gold-labeled complex probe. BN9m1 is used as the coating antibody for the C-line, and ProA is used for the T-line. The polymerization of colloidal gold particles enables us to detect the new coronavirus antigen’s appearance. Thus an in vitro rapid detection kit for virus detection can be made. Results: The positive detection rate of the antigen quality control serum with this colloidal gold reagent was 100%. The specificity was 100%, and the sensitivity was 1ng/ml. Conclusion: The nCOVID-19 antigen detection reagent (colloidal gold method) developed in this research has high specificity and sensitivity, and can be used in conjunction with nucleic acid detection. As a means of detecting nCOVID-19, it can achieve qualitative and rapid screening of samples with advantage such as accuracy, repeatability, and low cost.&lt;/p&gt;&lt;/div&gt;

Establishment and verification of a quantitative ELISA assay for detection of human serotype specific IgG against Streptococcus pneumoniae

Objective To establish a quantitative enzyme-linked immunosobent assay (ELISA) recommended by World Health Organization (WHO) for the detection of human serotype specific immunoglobulin G (IgG) against Streptococcus pneumoniae (Sp). Methods According to WHO′s operation manual for Enzyme linked immunosobent assay ELISA for the quantitative of Streptococcus pneumoniae serotype specific IgG (Pn PS ELISA), we established a ELISA method to detect serotype specific IgG against Sp in human serum specimens by using Sp capsular polysaccharide 4, 6B, 9V, 14, 18C, 19F, and 23F (purchased American Type Culture Collection, ATCC) as coating antigens and pneumococcal capsular polysaccharide antibody standard serum 007 sp (from National Institute for Biological Standards and Control, NIBSC) as standard serum. The accuracy and stability of the established method were evaluated using WHO′s calibration serum panel and internal quality control serum PnG. Results The concentration of 7 serotype specific coating antigens of Sp capsular polysaccharide (4, 6b, 9V, 14, 18C、19F and 23F) were determined and serotype specific IgG against Sp in human serum specimens were detected with the quantitative ELISA method established. More than 75% of measurements for 7 serotype specific Sp capsular polysaccharide IgG antibodies for 12 WHO calibration sera were within ± 40% of the measurement values assigned by reference laboratories of WHO, with an overall consistency rate of 86.9%, a correlation curve slope of 0.94, and an R2 of 0.99, respectively. In addition, the results of 20 consecutive internal quality control serum test showed that the coefficient of variation (CV) of different batches were less than 15%, which met the requirements of WHO intra-laboratory evaluation. Conclusion A quantitative ELISA method recommended by WHO for detection of serotype-specific Streptococcus pneumoniae IgG antibody in human serum was successfully established and verified. The accurate and stable method meet the requirements of disease surveillance and vaccine effect evaluation.

Clinical utility of validated gas chromatography–ion trap mass spectrometry in patients with anticholinesterase pesticides poisoning

Intentional or unintentional intake of anticholinesterase pesticides became common due to their extensive use in agricultural and domestic purposes, resulting in numerous poisoning cases. A simple, accurate, and sensitive gas chromatography-ion trap mass spectrometry-based method for the quantification of 12 anticholinesterase pesticides (monocrotophos, dimethoate, dichlorvos, azinphos-methyl, carbofuran, chlorpyrifos, dialifos, diazinon, malathion, parathion, methidathion, and terbufos) in serum was developed, and its utility in patients with alleged pesticides poisoning was assessed. The quantification was performed using liquid-liquid extraction by toluene/chloroform (4:1,v/v) with 500 μL of serum. On column limit of detection and limit of quantification were less than 50.00 μg/L. The recovery ranged from 97.54 to 103.23%. The calibration curves were linear (R2 > 0.9937). Accuracy was found to be between – 7.1 and 7.2%. Intra-day and inter-day reproducibility was less than 17% for the spiked quality control serum samples. The level of pesticide in serum quantified by the validated method correlated with clinical signs and symptoms, pseudo-cholinesterase activity, total atropine dose, length of hospital stay, and clinical outcome in 15 patients with alleged pesticide poisoning. The validated method may be used for monitoring and prognosis in patients with pesticide poisoning and diagnosis of poisoning in forensic toxicology.

The method comparison and the verification of precision of Mindray CL-6000i thyroid function tests (TFTs)

Abstract Objectives Thyroid diseases are the most frequent endocrine disorders and thyroid function tests (TFTs) are the most commonly requested endocrine tests. The reliable measurements of these tests are quite important. The aim of our study was to determine the bias and to verify the precision of the newly introduced Mindray CL-6000i immunoassay system in the guidance of CLSI guidelines. Methods A precision and bias study was performed in Mindray CL-6000i analyzer for FT3, FT4, TSH, Anti-TG, and Anti-TPO tests by using BioRad quality control (QC) materials and serum samples, respectively. Bland–Altman difference plot and Passing-Bablok regression analysis was made for method comparison with Beckman Coulter DXI 800 analyzer. Results The repeatability coefficient of variations (CVs) of FT3, FT4, TSH, Anti-TG, and Anti-TPO tests were ≤2.36, ≤1.66, ≤2.38, ≤3.48, and ≤3.31% while within laboratory CVs were ≤2.85, ≤4.61, ≤2.59, ≤3.78, and ≤3.60%, respectively. The mean differences between the two methods obtained from Bland–Altman analysis for FT3, FT4, TSH, Anti-TG, and Anti-TPO were defined to be −19%, 1.95%, −5.9%, −3.5%, and 7.3%, respectively. Conclusions Mindray CL-6000i had good precision in all tests, but the difference between the two methods in some tests shows that the harmonization and standardization of TFTs initiated globally is required.

1337. Development, Maintenance, and Application of Opsonophagocytic Assays to Measure Functional Antibody Responses to Support a 20 Valent Pneumococcal Conjugate Vaccine

BackgroundOpsonophagocytic assays (OPAs) are an important tool for assessing vaccine-induced functional antibody responses. OPAs are complex assays composed of many biological components (eg serum, complement sources, bacteria, and human phagocytes) which contribute to assay variability and may result in titer drift if not carefully controlled. Rigorous development and validation coupled with routine monitoring of assay performance are required to ensure that high-quality OPA serological data are consistently generated throughout the lifetime of existing and next-generation pneumococcal vaccines.MethodsOPA specificity was demonstrated by competing functional antibody activity with pneumococcal polysaccharides. Assay qualification/validation assessed accuracy, precision, and sample linearity. Assay performance over time was assessed through the implementation of quality control serum data tracking systems and longterm serum proficiency panels that are routinely tested during assay performance. Human quality control sera are included on each assay plate to ensure that each plate meets pre-specified acceptance criteria. Proficiency serum panels are comprised of individual human serum samples derived from subjects immunized with pneumococcal vaccines and are used to monitor performance across a range of serological titers and over time.ResultsThe OPAs were shown to be specific and reproducible. Monitoring of assay performance over time demonstrated that the assays are stable. For the 13 serotypes contained in 13vPnC reliable titers have been generated in over a decade of testing which is an essential prerequisite in the evaluation of next-generation pneumococcal conjugate vaccines such as 20vPnC, whose licensure depends on demonstration of non-inferiority to 13vPnC.ConclusionMaintenance and careful monitoring of high-quality assays to measure functional antibody responses, such as OPAs, is critical for the delivery of reliable serological data to support the advancement of pneumococcal vaccine programs. Pneumococcal OPAs must be rigorously maintained to ensure continuity of serological data over time and inform licensure decisions of next-generation vaccines as well as postmarketing and seroepidemiology studies.Disclosures All authors: No reported disclosures.

A paper-based electrochemical immunosensor with reduced graphene oxide/thionine/gold nanoparticles nanocomposites modification for the detection of cancer antigen 125

A paper-based electrochemical immunosensor was developed for the detection of cancer antigen 125 (CA125) by screen-printing technique. The reduced graphene oxide/thionine/gold nanoparticles (rGO/Thi/AuNPs) nanocomposites were compounded and coated onto the working electrode of immunosensor for CA125 antibody (anti-CA125) immobilization and detection signal amplification. The detection principle was based on the fact that the immunocomplex formed by specify binding of CA125 antibody and antigen could reduce the current response of thionine, which was proportional to the corresponding concentration of CA125 antigen. The immunoassay results showed that the linear range of CA125 was from 0.1 U mL−1 to 200 U mL−1 with the limit of detection (LOD) of 0.01 U mL−1 at signal to noise of 3. Quality control serum samples measured by our proposed immunosensor showed acceptable agreement with traditional ELISA method with the relative error less than 8.05%. The immunosensor exhibited good electrochemical performance with high reproducibility, reliability, stability and accuracy. The proposed immunosensor could be used for the determination of CA125 and had the potential for point-of-care testing (POCT) of other tumor marker.

DEVELOPMENT AND CHARACTERIZATION OF A SENSOR BASED ON CARBON NANOFIBERS: APPLICATION TO ACETAZOLAMIDE DETERMINATION IN PHARMACEUTICALS AND BIOLOGICAL FLUIDS

Acetazolamide (ACZ) is a carbonic anhydrase inhibitor that exhibits diuretic activity. In medicine, it is principally used in open-angle glaucoma, for prevention or amelioration of symptoms associated with acute high-altitude sickness and as an adjunct to other anticonvulsants in centrencephalic epilepsies. Furthermore, ACZ is sometimes used by athletes to mask the presence of doping substances, so its use has been banned in competitions. The aim of this work was the development of a sensor to determine ACZ in pharmaceuticals, as quality control way, and serum, for clinical and doping analyzes. The sensor has been developed modifying a glassy carbon electrode with carbon nanofibers. The electrochemical characterization of the sensor was performed by cyclic voltammetry using the redox mediator potassium ferrocyanide. ACZ electrochemical behavior was studied as well. Measurements were performed in a conventional three electrodes cell using differential pulse voltammetry. The influence of some experimental variables involved in the preparation and performance of the sensor –amount of modifier, supporting electrolyte, pH, scan rate and pulse amplitude– were optimized. This methodology provided a linear calibration plot for ACZ in the 1 – 17 μM concentration range. Furthermore, the proposed sensor exhibited suitable analytical properties, with detection and quantification limits of 0.06 μM and 0.2 μM respectively; analytical sensitivity of 1.142 μA/μM, repeatability of 0.72 %, and it was applied to determine ACZ in pharmaceuticals (tablets) and spiked human serum, being an excellent tool to perform quality control and antidoping control.

Evaluation of 2015-2016 MOTAKK HBV DNA and HCV RNA external quality assessment national program results

MOTAKK, as a national external quality control program has been launched to evaluate the molecular detection of viral infections including HBV DNA and HCV RNA in molecular microbiology diagnostic laboratories in Turkey. This program is prepared in compliance with ISO 17043:2010 (Conformity assessment general requirements for proficiency testing) standards, and aims to take the place of external quality control programs from abroad, contributing to standardization and accuracy of molecular diagnostic tests in our country. The aim of this study was to evaluate 2015 and 2016 results of the MOTAKK External Quality Control Program for HBV DNA and HCV RNA viral load . The calls were announced on the web page of MOTAKK (www.motakk.org). The quality control samples were sent to participating laboratories in 2015 and 2016. Main stocks were prepared from patients with chronic hepatitis B and C who had viral load detection with reference methods according to WHO reference materials for viral load studies to improve quality control sera. From these main stocks, samples with different viral loads were prepared from dilutions of plasma with HBV, HCV, HAV, HIV, Parvovirus B19 and CMV negative serologic markers. Quality control samples were sent to the participating laboratories along with the negative samples in the cold chain. The laboratories accomplished the related tests within 2-3 weeks and entered their results on the MOTAKK web page. These results were analysed according to ISO 13528 (Statistical methods for use in proficiency testing by interlaboratory comparison) and scoring reports were created by a software developed by MOTAKK and sent to participating labs. Each laboratory evaluated their own results in comparison with the other laboratory results, reassessed the tests via observing the distance from the mean result and the reference values. The number of laboratories participating in the HBV DNA and HCV RNA external quality control program was 70-73 in 2015-2016. Participants were able to comply with the program tools, registering, entering results and receiving the results reports without problem. In HBV panel, 72.6-89.1% and 84.7-90.3% of the participant laboratories were in 1 standard deviation (SD) in 2015-2016, respectively. In HCV panel, 70.8-89.1% and 84.7-90.3% of the participant laboratories were in 1 SD in 2015-2016, respectively. A national external quality control program for HBV DNA and HCV RNA in Turkey has been prepared for the first time with this project and implemented successfully. All the data provided in the MOTAKK external quality control program final report, compensate all the data provided by the quality control program final reports from abroad; additionally, the report allows comparison of used technologies and commercial products.

Comparison of two commercial quality control sera for adrenocorticotropin (ACTH) used in Elecsys® immunoassay system.

The purpose of our study was to investigate whether the storage time and temperature of internal quality control (IQC) material influence the result of ACTH in IQC measurements. Five levels of IQC materials from two manufacturers were tested through the precision of ACTH, the three freeze/thaw cycles, and the storage time and temperature to evaluate the stability of IQC material. All commercial control materials were simultaneously tested three times a day for five consecutive days. Total precision of three levels of Bio-Rad IQC sera was 13.93%, 16.45%, and 15.98%, respectively, but repeatability was <2%. The concentration of ACTH decreased by 30%-50% after 3 freeze/thaw cycles. At room temperature, the concentration of ACTH from 3 levels decreased by 16.60%, 17.98%, and 17.20%, respectively, after 0.5hours, and 70.54%, 74.36%, and 72.03%, respectively, after 4hours. However, after 2hours of storage at 4°C, the decline in the measured ACTH IQC was 8.04%, 11.84%, and 10.11%, respectively. Total precision of Roche IQC was 1.17% and 1.08%, respectively. After 3 freeze/thaw cycles, the concentration of ACTH decreased <5%. After 4hours, the change of ACTH still steadied within 5% both at the room temperature and at 4°C. Roche is a better choice for ACTH of IQC material in Elecsys® immunoassay system in our study. If Bio-Rad control materials be used in Elecsys® immunoassay system for ACTH IQC testing material, it should be stored at 4°C and testing should be completed within 1hours.

Guinea pig complement potently measures vibriocidal activity of human antibodies in response to cholera vaccines.

The vibriocidal assay using guinea pig complement is widely used for the evaluation of immune responses to cholera vaccines in human clinical trials. However, it is unclear why guinea pig complement has been used over human complement in the measurement of vibriocidal activity of human sera and there have not been comparison studies for the use of guinea pig complement over those from other species. Therefore, we comparatively investigated the effects of complements derived from human, guinea pig, rabbit, and sheep on vibriocidal activity. Complements from guinea pig, rabbit, and human showed concentration-dependent vibriocidal activity in the presence of quality control serum antibodies. Of these complements, guinea pig complement was the most sensitive and effective over a wide concentration range. When the vibriocidal activity of complements was measured in the absence of serum antibodies, human, sheep, and guinea pig complements showed vibriocidal activity up to 40-fold, 20-fold, and 1-fold dilution, respectively. For human pre- and post-vaccination sera, the most potent vibriocidal activity was observed when guinea pig complement was used. In addition, the highest fold-increases between pre- and post- vaccinated sera were obtained with guinea pig complement. Furthermore, human complement contained a higher amount of V. cholerae- and its lipopolysaccharide-specific antibodies than guinea pig complement. Collectively, these results suggest that guinea pig complements are suitable for vibriocidal assays due to their high sensitivity and effectiveness to human sera.

Chemiluminescence systems; do all lead to same results in prolactin analysis?

BackgroundHuman prolactin (PRL) is a hormone that is mainly secreted by lactotroph cells of the anterior pituitary gland and is involved in many biological processes including lactation and reproduction. Prolactin level may be determined quantitatively in serum by many different systems including chemiluminescence systems. However, comparison of the measured values between systems is difficult.MethodsThe prolactin values obtained and compared in two chemiluminescence systems; AUTOBIO DIAGNOSTICS MICROPLATE LUMOMETER and LIAISON XL Analyzer using BioRad tri level serum quality control materials and serum samples from n = 44 female patients; (Age mean & range) = (33: 21–65) years.ResultsObtained PRL mean and range in Autobio and Liason systems were X = 414.8 ± 230.0; Range: 25.7–980.9 μlU/mL & X = 391.7 ± 225.6; Range: 26.0–991.4 μlU/mL respectively. Both system’s results were correlated (Pearson product moment correlation r = 0.97 at p = 0.01 and Regression Analysis).ConclusionBecause of the differences between CLIA systems the authors conclude laboratories measuring range for PRL be accomplished on particular analyzer and verified against reference intervals stated by the manufacture. More importantly, consecutive PRL level determinations and patients follow up should be performed on only one analyzer rather than different analyzers. In this regard, mentioning the method and system type on the final laboratory reports become important and verify that a laboratory considers the clinical aspects of laboratory request as well as the quality assurance in performing the PRL determination.

Preparation and evaluation of laboratory quality control materials for the detection of IgG anti-A/B

Abstract Background: This research was aimed at preparing laboratory quality control materials for the detection of IgG anti-A/B and evaluating them in preliminary applications. Methods: Mixed IgG anti-A and anti-B sera were used as quality controls for measuring IgG anti-A/B titers. The quality control materials were packaged with sodium azide as preservative, and stored at –30°C. Twenty repeated measurements were done in succession. After the quality control values were determined, the quality control materials were used preliminarily. Quality controls and the untested blood samples were assayed at the same time within 6 months. Results: The mean IgG anti-A titer of the high-value quality control serum was 1:550 and ranged from 1:225 to 1:1100 for the control. The mean IgG anti-B titer of the high-value quality control serum was 1:269 and ranged from 1:135 to 1:538 for the control. The mean IgG anti-A and B titer of the low-value control serum was 1:32, with a quality control range of 1:16–1:64. Conclusions: Laboratory quality control materials in the measurement of IgG anti-A/B titers were developed successfully. Standardization of the assay procedure and quality control survey would be necessary for the accuracy of measurement.