Proficiency Testing Performance Research Articles

A-118 Sigma Metric Performance of Chemistry Assays on 4 Instrument Systems

Abstract Background Chemistry panels play a crucial role in determining a person’s general health and well-being. These tests evaluate electrolyte balance and the status of several major organs. The Comprehensive Metabolic Panel (CMP) and Lipid Panel constitute approximately 87% of the blood tests prescribed in medical laboratories. Laboratories monitor assay performance by performing proficiency testing using quality controls (QC). College of American Pathologists (CAP) data is useful for laboratories to compare their proficiency testing performance to other laboratories and instrument systems. Sigma metrics serve as a valuable tool for laboratories to assess the quality and accuracy of their tests. Sigma scores vary from 0 to 6, with the 6 score designated as world-class performance, 5 as excellent, 4 as good, 3 as marginal, and 2 as poor. The analytical performance of 16 clinical assays from Abbott, Beckman, Roche, and Siemens instrument systems were compared using Sigma metrics. Methods Sigma metrics of 16 chemistry analytes were compared across 4 instruments system using CAP data from three reports (C-A 2023, C-C 2023 and C-B 2022). The 4 systems evaluated were Abbott Alinity ci, Beckman AU, Roche COBAS c500/c303 and Siemens Atellica CH. Method imprecision was estimated for each assay using the cumulative coefficient of variation or standard deviation for each assay at a single QC concentration and calculating the average sigma. Since sigma levels can be concentration-dependent, an equivalent CAP sample concentration was chosen for each instrument system evaluation. Method bias was estimated by evaluating each method QC mean to the peer group mean. Sigma values were calculated for each method as Sigma = (TEa - |Bias|) / Precision using the allowable total error from 2014 Clinical Laboratory Improvement Amendments (CLIA) proposed acceptance limits. Average Sigma values were generated for each analyte and graded as an optimal Sigma score. Results The sigma scores varied across assays and instrument systems. Abbott demonstrated the best overall performance. Specifically, the Abbott Alinity system had the highest number (7/16, 44%) of assays at 5 sigma or higher, with Siemens showing the lowest number of assays at 5 Sigma or higher (1/16, 6%). Of the 16 assays evaluated, Abbott has the fewest assays at or below the 3 sigma threshold (5/16) when compared to Roche (7/16), Beckman (7/16), and Siemens (9/16). Sigma scores were comparable between the Abbott ARCHITCT and Alinity clinical chemistry systems. Conclusions Sigma metrics are useful in assessing the performance of clinical assays. Assays with high Sigma have better performance due to lower imprecision and higher accuracy. None of the instrument systems demonstrated optimal six sigma performance for all analytes. However, Abbott demonstrated the best overall performance.

RNA Sequencing for Solid Tumor Fusion Gene Detection: Proficiency Testing Practice and Performance Comparison.

Next-generation sequencing-based approaches using RNA have increasingly been used by clinical laboratories for the detection of fusion genes, intragenic rearrangements, and exon-skipping events. Correspondingly, the College of American Pathologists (CAP) has advanced RNA sequencing proficiency testing (PT) to ensure optimal performance of these assays. To report on laboratory performance and practices of RNA sequencing for the detection of fusion genes, intragenic rearrangements, and exon-skipping events using CAP PT data from 8 mailings (2018-A through 2021-B). CAP PT RNA sequencing program results from 153 laboratories across 24 proficiency test specimens, interrogating 22 distinct engineered fusion transcripts, were analyzed for correct identification of the fusion event, associated performance variables, and laboratory practices. Overall, the 4-year program detection rate (sensitivity) was 95.5% (1486 of 1556 results). False-negative rates were 3.6% (53 of 1463) and 18.3% (17 of 93) for fusion gene and intragenic rearrangement/exon-skipping events, respectively. Only 19 false-positive results were reported among the 8 PT mailings, and most were likely the result of preanalytical or postanalytical errors. There were no practice characteristics (eg, instrumentation, sequencing method) significantly associated with the fusion detection results. These data reveal a high overall sensitivity and specificity for fusion gene detection by participating laboratories using clinical RNA sequencing. Performance was comparable across all laboratories, regardless of methodology. The fraction of false-negative results for intragenic rearrangement/exon-skipping events was greater than that for the chimeric fusion genes. False-negative results could not be attributed to any specific practice characteristics.

Busulfan Interlaboratory Proficiency Testing Program Revealed Worldwide Errors in Drug Quantitation and Dose Recommendations.

The clinical outcomes of busulfan-based conditioning regimens for hematopoietic cell transplantation (HCT) have been improved by personalizing the doses to target narrow busulfan plasma exposure. An interlaboratory proficiency test program for the quantitation, pharmacokinetic modeling, and busulfan dosing in plasma was developed. Previous proficiency rounds (ie, the first 2) found that 67%-85% and 71%-88% of the dose recommendations were inaccurate, respectively. A proficiency test scheme was developed by the Dutch Foundation for Quality Assessment in Medical Laboratories (SKML) and consisted of 2 rounds per year, with each round containing 2 busulfan samples. In this study, 5 subsequent proficiency tests were evaluated. In each round, the participating laboratories reported their results for 2 proficiency samples (ie, low and high busulfan concentrations) and a theoretical case assessing their pharmacokinetic modeling and dose recommendations. Descriptive statistics were performed, with ±15% for busulfan concentrations and ±10% for busulfan plasma exposure. The dose recommendations were deemed accurate. Since January 2020, 41 laboratories have participated in at least 1 round of this proficiency test. Over the 5 rounds, an average of 78% of the busulfan concentrations were accurate. Area under the concentration-time curve calculations were accurate in 75%-80% of the cases, whereas only 60%-69% of the dose recommendations were accurate. Compared with the first 2 proficiency test rounds (PMID 33675302, October, 2021), the busulfan quantitation results were similar, but the dose recommendations worsened. Some laboratories repeatedly submit results that deviated by more than 15% from the reference values. The proficiency test showed persistent inaccuracies in busulfan quantitation, pharmacokinetic modeling, and dose recommendations. Additional educational efforts have yet to be implemented; regulatory efforts seem to be needed. The use of specialized busulfan pharmacokinetic laboratories or a sufficient performance in busulfan proficiency tests should be required for HCT centers that prescribe busulfan.

Proficiency Testing Performance for Point of Care Glucose Users in a Tertiary Hospital in Kenya

Abstract Introduction/Objective Introduction: Point of Care (POC) blood glucose measurements are widely used for monitoring diabetes in hospitals. Ensuring quality of POC glucose is important for patient safety. Proficiency testing (PT) where POC users are provided with samples to analyze in the same way as they would patient samples, and the test results are compared with those of peers, is especially important for hospitals with multiple glucose meters where multiple operators with varying levels of education and experience are performing POC glucose analysis. Objective To evaluate the performance of POC glucose users at a tertiary hospital in Nairobi, Kenya. Methods/Case Report Methodology: The study was conducted at the Kenyatta National Hospital (KNH), an 1800 bed public teaching and referral hospital located in Nairobi, Kenya.Nurses in 46 wards and clinics who use blood glucose machines (BGM) were given low and high glucose quality control (QC) materials to analyze using BGMs like patient samples. The results of each ward were analyzed. Comparison of each participant was made with the group (consensus values) and the central laboratory (assigned values), and graded as acceptable or unacceptable. Results (if a Case Study enter NA) Results:Most participants obtained acceptable glucose results but 7.6% and 13% results were unacceptable when consensus values and assigned values were used respectively. Two participants (4.3%) obtained unacceptable with both low and high glucose controls. Conclusion The unacceptable results indicate need for improvement, and two BGM users who should be trained and their competency assessed to ensure quality of glucose tests.

Predicted standard deviation of proficiency testing performance in animal nutrition methods

The empirical correlations of the results of over ten years of a proficiency testing of animal nutritional analysis conducted by Embrapa were evaluated. The results demonstrate the similarity of the Horwitz equation proposal, but it is desirable to use individual equations related to the different analyses performed by the laboratories. Using these equations enables a more realistic assessment of possible systematic errors and analytical processes, improving laboratory performance and providing the most reliable results.

Six-Year Experience (2013-2018) With College of American Pathologists Programs at King Hussein Cancer Center in Jordan

Abstract Objectives Proficiency testing (PT) includes interlaboratory comparisons that are organized regularly to assess the performance of individual laboratories for specific tests or measurements and it is used to monitor laboratories’ continuing performance. Background The College of American Pathologists (CAP) requires laboratories to participate in PT programs and to perform the investigation and root cause analysis for unsatisfactory PT results, which is valuable to improve the laboratory performance. Methods The data were extracted from the CAP PT results of the laboratory from 2013 to 2018 in the areas of Biochemistry, Immunology, Hematology, Microbiology, Anatomic Pathology and Cytology, and Blood Bank. The data were PT scores and consisted of values between 0 and 100, representing the percentage of correct response for each analyte. Results There were 211 analytes (502 event) in 2018, 215 analytes (547 event) in 2017, 204 analytes (531 event) in 2016, 210 analytes (519 event) in 2015, 228 analytes (443 event) in 2014, and 158 analytes (528 event) in 2013 that were covered by CAP PT surveys in different laboratory areas. Over the 6 years of experience, there were 57 (1.86%) unsatisfactory results for all PT events. It was seen that the rates of unsatisfactory results in that period were gradually decreased with each year of experience, which was 1.1% (2018), 1.6% (2017), 1.9% (2016), 1.5% (2015), 2.4% (2014), and 2.6% (2013). The top 3 reasons for unacceptable results were random error, analytical error, and procedural error, which accounted for 21.0% random error (2013 (9%), 2014 (4%), 2015, 2016, 2017, & 2018 (2%)), 19.3% analytical error (2013 (2%), 2014 (5%), 2015 (5%), 2016 (3.5%), 2017 (2%), & 2018 (1.8%)), and 17.5% procedural error (2013 (4%), 2014 (4%), 2015 (0%), 2016 (2%), 2017 (5%), & 2018 (3.5%)). Conclusion The proficiency testing performance showed a trend of improvement from 2013 to 2018, which contributed to the improvement of laboratory performance and declining the unacceptable results that affected positively on patient test performance.

An Evaluation of Methods for Assessing the Competence of Laboratories Based on Performance in the GeoPT Proficiency Testing Scheme

The original certification protocol, published by the International Association of Geoanalysts in 2003, specified that the competence of laboratories selected as competent to contribute certification measurements should be evaluated from their performance in the GeoPT proficiency testing programme. Round 39 of the IAG GeoPT proficiency testing programme provided an opportunity to examine four methods of evaluating laboratory competence based largely on the use of proficiency testing z‐scores as performance indicators. This opportunity arose because two test materials were co‐analysed by participating laboratories in this round: a syenite, SyMP‐1, supplied by the USGS, and an established CRM, the nepheline syenite, CGL 006. The performance of laboratories was assessed in four ways; in each case, consensus values and their uncertainties as derived from selective data sets of competent laboratories were compared with results derived from the routine GeoPT data assessment, involving all submitted measurements. An overall comparison of results showed no significant statistical differences in either consensus values or uncertainties between these data sets. This conclusion was unexpected and calls into question the widely held assumption that ‘better’ consensus data would be obtained from a subset of laboratories judged to be competent on the basis of proficiency testing performance indicators.

Taking laboratory uncertainties into account in the Hampel estimator

According to ISO/IEC 17025:2017, testing and calibration laboratories should apply procedures for estimating measurement uncertainty. It would thus make sense to include these uncertainty estimates in the evaluation of laboratory performance in proficiency testing. According to ISO 13528:2015, submitted laboratory-specific uncertainties can be taken into account in the assessment of the performance of PT participants by means of $$\zeta$$ (or $$E_{n}$$ ) scores. It is important to note, however, that the laboratory uncertainties are not taken into account in the actual estimation of consensus means. In this paper, a proposal for a modification of the Hampel estimator is presented. In the original Hampel estimator, the laboratory weights are determined on the basis of a single reference quantity (e.g. $$\sigma_{\text{pt}}$$ ). In the modified estimator, this single reference quantity is replaced by the laboratory-specific uncertainties. Thus, all available information is taken into consideration in the estimation of the consensus mean, ensuring a greater level of reliability. Moreover, since $$\sigma_{\text{pt}}$$ is no longer needed in the computation of the consensus mean, the requirements regarding minimum participant numbers can be relaxed.

Influence of Language Learning Strategies to the English Proficiency Test Performance of College Students

Learning of English as second and even foreign language has been stressed out in all levels of education. Thus, teachers and researchers have been focusing on describing externally observable behaviors of language learners, followed by attempts to label categorized strategic behaviors and link them to language proficiency. This descriptive correlational study aimed to describe the extent of learners’ use of the language learning strategies (LLS) and determine its relationship with the English proficiency test performance of college students (N=82). The Oxford’s Strategy Inventory Language Learning (SILL) and a standardized College English Proficiency Test were the main instruments of the study. Results showed that memory, metacognitive, cognitive, compensation, organizing and evaluation and affective learning strategies do not significantly affect students’ English proficiency test performance; whereas social learning strategies is a strong predictor of students’ English proficiency test performance. This research provides a basis for utilizing social learning strategies as an intervention for improving students’ English proficiency.

Boost Up Quality Assurance through Regular Evaluation of Proficiency Testing Performance

Background: Participation in External Quality Assessment (EQA) program with practice of Internal Quality Control (IQC) is the excellent indicator of good laboratory practice (GLP) to assure quality services. EQA is an essential component of Quality Assurance to assess the analytical performance compared within same methods of other laboratories. It is also important to detect equipments failure, identifying reagent problems, reviewing staff training as well as to initiate and evaluate corrective action timely.Methods: This is descriptive analysis of the feedback received from EQAS body for twenty routine biochemical parameters which are most commonly performed in the Clinical Biochemistry Laboratory of Dhulikhel Hospital. Variation Index Score (VIS), Overall Mean VIS (OMVIS) and Standard Deviation Index (SDI) of all parameters for the year 2014 and 2015 were analyzed statistically.Results: On the analysis of twenty routine biochemical parameters regularly participated in EQAS, over all mean variation index score (OMVIS) of individual tests found 55%, 30% and 15% under good, very good and satisfactory category respectively.Conclusion: Participation and periodic evaluation of EQAS indicators along with practice of internal quality control has been galvanizing good laboratory practice and scientifically it boost up quality service in clinical laboratories.

Proficiency testing performance of Turkish laboratories on determination of relative composition of fatty acids in sunflower oil

Proficiency testing performance of Turkish laboratories on determination of relative composition of fatty acids in sunflower oil

Proficiency testing performance of Turkish laboratories on determination of relative composition of fatty acids in sunflower oil

Proficiency testing performance of Turkish laboratories on determination of relative composition of fatty acids in sunflower oil

Laboratory competence evaluation through proficiency testing - mycotoxins in food

Laboratory for analysis of mycotoxins in food at the Institute of Public Health of Vojvodina (Novi Sad, Serbia) participated in 15 proficiency testing schemes in period 2012-2016, comprising 22 determinations of regulated mycotoxins: aflatoxins B1, B2, G1, G2 and M1, ochratoxin A, deoxynivalenone, zearalenone, fumonisins and patulin, in different food commodities: wheat, corn, barley, breakfast cereals, infant food, milk, wine and fruit juice. Analyses were carried out by high performance liquid chromatography with ultraviolet (patulin, deoxynivalenol) or fluorescence detection (aflatoxin M1, ochratoxin A, zearalenone) using o-phthalaldehyde precolumn derivatization (fumonisins) or UV postcolumn derivatization (aflatoxins B1, B2, G1, G2), following clean-up on immunoaffinity columns with specific antibodies, except in case of patulin when solvent extraction and solid-phase C-18 clean-up were used. Laboratory performance assessed in terms of z scores showed all satisfactory results. In depth evaluation revealed following distribution of z scores (absolute values): 59.1% up to 0.5, 36.4% between 0.5 and 1.0, and 4.5% above 1.0. Analysis of trends performed for multiple determinations of individual mycotoxins showed several changes of z score to better or worse rank. Overall assessment of the performance in proficiency testing demonstrated laboratory competence for analysis of mycotoxins in food.

Comment on “Returns to Education and Skills in the Labor Market: Evidence from Japan and Korea”

Comment on “Returns to Education and Skills in the Labor Market: Evidence from Japan and Korea”

External quality assessment of AFB smear microscopy performances and its associated factors in selected private health facilities in Addis Ababa, Ethiopia.

Tuberculosis (TB) is still a public health problem in sub Saharan African countries. In resource-limited settings, TB diagnosis relies on sputum smear microscopy, with low and variable sensitivities, especially in paucibacillary pediatric and HIV-associated TB patients. Tuberculosis microscopy centers have several weaknesses like overworking, insufficiently trained personnel, inconsistent reagent supplies, and poorly maintained equipments; thus, there is a critical need for investments in laboratory infrastructure, capacity building, and quality assurance schemes. The performance of TB microscopy centers in the private health facilities in Addis Ababa is not known so far. The main objective of the study was to assess laboratory performance of acid fast bacilli (AFB) smear microscopy and its associated factors in selected private health facilities in Addis Ababa, Ethiopia. A cross-sectional study was conducted in 33 selected private health facilities of Addis Ababa, Ethiopia comprising 7 hospitals, 2 NGO health centers, 23 higher clinics and 1 diagnostic laboratory that provide AFB smear microscopy services. The study was conducted from January to April 2014. A total of 283 stained sputum smears were randomly collected from participant laboratories for blinded rechecking, 320 panel slides were sent to 32 microscopy centers to evaluate their performance on AFB reading, staining and reporting. Checklists were used to assess quality issues of laboratories. Data were captured, cleaned, and analyzed using SPSS version 16.0; χ2 tests, kappa statistics were used for comparison purpose. P value < 0.05 considered statistically significant. Among the 32 participant laboratories, 2-scored 100%, 15 scored 80-95% & the remaining 15 scored 50-75% for overall proficiency test performance. There were 10 (3.15%) major errors and 121 (37.8%) minor errors. The sensitivity, specificity, PPV and NPV of panel reading by microscopy centers were 89%, 96%, 96%, and 90% respectively. Out of 283 randomly selected slides for blind rechecking, 11 (3.9%) slides interpreted falsely for AFB, with overall agreement of 97.5%, sensitivity of 88.4% and specificity of 99.3%. In terms of slide quality assessment, 71.6% of AFB slides were graded as good for evenness, cleanness, thickness, size, staining and labeling. The performance score for AFB slide evenness was 56.9% (161 slides) and for labeling quality was 90.8% (257 slides); having significant difference in slide quality (p value < 0.05). On-site evaluation indicated problems in terms of infrastructure, standard operating procedure, reagent quality; equipment maintenance, data management and training issues. Most of the health facilities had poor maintenance scheme for microscope (53.5%) and poor inventory management (25.0%) system. Microscopy centers that scored a proficiency of 75.5%; which is below the acceptable minimum score of 80% and an overall error rate of 3.9% for blinded rechecking needs attention. Moreover, there are gaps identified through on site assessment including poor SOP, reagent quality, equipment maintenance, data management & lack of updated training on AFB microscopy techniques, requiring a concerted effort to alleviate the bottle neck problems and strengthening the public private partnership to control TB.

Relationship Between a Standardized Tackling Proficiency Test and Match-Play Tackle Performance in Semiprofessional Rugby League Players.

This study examined the relationships between tackling ability, playing position, muscle strength and power qualities, and match-play tackling performance in semiprofessional rugby league players. Sixteen semiprofessional rugby league players (mean ± SD age 23.8 ± 1.9 y) underwent tests for muscle strength and power. Tackling ability of the players was tested using video analysis of a standardized 1-on-1 tackling drill. After controlling for playing position, players were divided into "good tackler" or "poor tackler" groups based on the median split of the results of the 1-on-1 tackling drill. A total of 4547 tackles were analyzed from video recordings of 23 matches played throughout the season. Maximal squat was significantly associated with tackling ability (rS = .71, P < .05) and with the proportion of dominant tackles (rS = .63, P < .01). Forwards performed more tackles (P = .013, ES = 1.49), with a lower proportion of missed tackles (P = .03, ES = 1.38) than backs. Good tacklers were involved in a larger proportion of dominant tackles and smaller proportion of missed tackles than poor tacklers. These findings demonstrate that lower-body strength contributes to more effective tackling performance during both a standardized tackling assessment and match play. Furthermore, players with good tackling ability in a proficiency test were involved in a higher proportion of dominant tackles and missed a smaller proportion of tackles during match play. These results provide further evidence of the practical utility of an off-field tackling assessment in supplying information predictive of tackling performance in competition.

First Indonesian proficiency testing scheme using reference values for cadmium, copper, and iron in drinking water

Proficiency testing (PT) performance evaluation based on a consensus value for the assigned value is commonly used because it is considered cheap and thus easily approachable, and also gives a good confidence to the PT participants, since their results contribute to the establishment of the assigned value. However, the consensus value has a weakness in that it could be significantly different from the true value due to largely inexperienced laboratories participating in the PT scheme. Starting from 2013, the Research Center for Chemistry, Indonesian Institute of Sciences, tried to conduct a PT scheme using reference values for cadmium, copper, and iron in drinking water samples in order to increase the reliability of measurement results from Indonesian testing laboratories. The PT sample is a candidate reference material with reference values which were calculated from the measurement results using two comparable methods of inductively coupled plasma optical emission spectrometry and graphite furnace atomic absorption spectrometry. Data evaluation of the PT results was based on ISO 13528 and calculated with the z-score statistic method using PROLAB software. Sixty-two laboratories from the whole Indonesian region participated, and about 94 % and 71 % showed good performance for copper and iron, respectively, since the values were above the quantification limit, and the mean of the result was close to the reference values. However, there was a big difference between the mean and the reference value for cadmium due to the lack of knowledge and experience of most laboratories in Indonesia to measure the trace concentrations of elements such as cadmium. The results of the participants all together were so poor, that the use of consensus value would have been of less quality than the reference value. Therefore, the only way to evaluate cadmium in this PT scheme was by using the reference value.

Inherited metabolic disorders: Quality management for laboratory diagnosis

BackgroundThe advancements in laboratory technology and knowledge of the mechanisms behind metabolic disorders have facilitated accurate and reliable laboratory testing in screening, diagnosis and treatment of inherited metabolic disorders. Therefore, quality assurance and improvement in diagnostic proficiency have become essential in this area. In most developing countries, standard practices for quality assurance in testing of enzymes, hormones and metabolites involved in these genetic disorders have not been fully implemented. We highlight the benefits of quality assurance and aim to create awareness for greater compliance with the criteria established for quality control to ensure accuracy in biochemical genetic testing. MethodsEstablishing the limit of detection and testing range for each analyte and enzyme are useful as a reference while setting up new assays. To minimize error, %CV should be monitored regularly. Evaluation of proficiency testing performance provides scope to the laboratory for improving testing quality. ResultsLow precision seen in lysosomal enzyme assays does not undermine their diagnostic efficacy as differentiation between patients and normal subjects is possible by setting % coefficient of variation cutoffs. ConclusionsThe study will facilitate the collaboration with other screening and diagnostic systems and help in development of new laboratory standards.

Evaluation of Laboratory Performance with Quality Indicators in Infectious Disease Hospital, Kano, Nigeria

Background: In January 2010, the implementation of quality management systems toward WHO-AFRO laboratory accreditation commenced in the Antiretroviral Treatment Laboratory of the Infectious Disease Hospital, Kano, Nigeria. Quality improvement projects were instituted in 2011 in line with ISO 15189 requirements for accreditation of medical laboratory. In this study we evaluated the performance of the laboratory through some set of quality indicators (QI). Methodology: This was a retrospective study to evaluate laboratory QIs monitored from January 2011 to December 2013. The QIs were specimen rejection rate (SSR), turnaround time (TAT), proficiency testing performance (PTP) and client satisfaction survey (CSS). Data was collected into an excel file for analysis and percentage performance compared among years. SSR & TAT were evaluated with the Sigma scale. Results: A total of 7920 (2194 in 2011, 2715 in 2012, 3011 in 2013) specimens were received for testing. 22 (0.28%) specimens were rejected and 81 (1.02%) specimens’ results were reported after the acceptable TAT, giving a Sigma level of 4.27 and 3.82 for SSR and TAT respectively. There was steady improvement in PTP: CD4+ from 67% in 2011 to 90% in 2013, hematology from 81% in 2012 to 83% in 2013, blood film reading 79% in 2011 to 83% in 2013 and chemistry from 90% in 2011 to 93% in 2013. HIV serology recorded 100% throughout. CSS increased from 59% in 2012 to 78% in 2013. However, there was no statistically significance difference reported for PTP and CSS over the years (P > 0.05). Conclusion: The study highlights the need to continuously evaluate QIs and calls for more effort to improve on PTP and focuses on understanding and improving on clients concerns.

Proficiency Testing and Laboratory Performance in the Field of pH Measurement: An Indonesian Experiment

Proficiency testing (PT) for pH measurements for two consecutive years (2013 and 2014) in Indonesia have been conducted to discern the current condition of participant laboratories regarding their capacity on the pH measurement and to evaluate the effect on usage of the standard reference material. On 2013, two buffer solutions (phthalate and phosphate) and their corresponding standard reference solutions were distributed to the participant laboratory. While on 2014, the PT was conducted for citrate buffer solution but no corresponding standard reference solution was provided; thus the participant laboratory can used their own reference standard. The PT for both phthalate and phosphate buffer in 2013 were completed by involving 10 participant laboratories. In 2014, the PT was conducted with 90 participant laboratories. The PT results were evaluated based on ISO 13528:2005(E). From 10 participant laboratories on 2013, it was found that 80% of participant for phthalate buffer and a 70% of participant for phosphate buffer attain a satisfactory category. For the PT of citrate buffer on 2014, it was found that 54% of 90 participant have held a satisfactory category. Moreover, form the evaluation regarding the effect of standard reference material usage; it was found that a better result can be achieved by using a reference buffer solution from the RCChem LIPI as the PT provider rather than by using their own standard reference. Overall, it can be concluded that capability of the laboratory in Indonesia regarding pH measurement is needed to be improved by which more attention is given in term of the use and handling of standard buffer solution.