calibration verification and linearity

For other problems with high or low specimens, assess pre-analytic variables including sample handling and degradation. No, the laboratory has always been responsible for calibration verification or “checking” calibration. Pearls of Laboratory Medicine Our modern laboratory and streamlined processes allow us to consistently manufacture products that are of the highest quality, are easy-to-use and are incredibly efficient. Here is a table listing the mean observed values of the raw data for the measurements for D- dimer obtained for each sample. This is because in the past, coagulation testing was primarily clot-based testing using instruments that were not calibrated to measure the concentration of an analyte. CVA (Calibration Verification Assessment) and CVA for CELL-DYN are assayed linearity control kits used to determine the patient reportable range and linear performance of three- and five-part differential hematology analyzers by testing the upper and lower limits. The Validate D-Dimer calibration verification and linearity test kit from LGC Maine Standards, Cumberland Foreside, Maine, has received FDA premarket notification (510(k)) clearance for use on Stago STA-R Evolution analyzers. Samples can be tested in duplicate for calibration verification which may be slightly different than the process for testing patient samples. By performing a linearity experiment! For the former, the lab may need to acquire additional samples near the low end and the high end for analysis. The AMR is the range of concentrations of an analyte that a method can directly measure without any dilution, concentration, or other pretreatment. It is a check on linearity as well as calibration. The checklist also states that linearity studies are not required for calibration and calibration verification of CBC instruments. Lastly, consider the possibility of clerical errors if results from the instrument were transcribed into another file for data analysis. If patient samples were used, were they processed according to standard operating procedure prior to testing to ensure adequate mixing, centrifugation, or were other necessary processing steps were taken? VALIDATE® products allow clinical laboratories to complete their required linearity and calibration verification, maximizing the reportable range while minimizing manual dilutions. I am an Assistant Professor of Pathology at the University Of Utah Department Of Pathology and Medical Director of clinical laboratories at University of Utah Hospital and Clinics. The application in the calibration field is more on the development (design and development) of a calibration procedure in order to meet certain requirements. It is fairly common to encounter situations where an assay is linear over the tested range, however, the samples tested at the low end or the high end of the AMR are problematic. This program, designed for laboratories, satisfies the requirements for scheduled calibration verification and verification of the analytical measurement range as specified in the CAP Laboratory Accreditation Program and Current Clinical Laboratory Improvement Amendments (CLIA) Regulations Section 493.1255 for most analytes. These standards can be found on the Joint Commission internet site. This program, designed for laboratories, satisfies the requirements for scheduled calibration verification and verification of the analytical measurement range as specified in the CAP Laboratory Accreditation Program and Current Clinical Laboratory Improvement Amendments (CLIA) Regulations Section 493.1255 for most analytes. If a kit was used, were the kit’s instructions followed? How can labs meet the regulatory requirements? Methodology has evolved since then and many coagulation laboratories use methods which may be calibrated and measure a concentration of an analyte. Calibration verification is also indicated in the following situations: whenever there is a complete change in the set of reagents to a new lot, there is major preventative maintenance or replacement of critical parts of the instrument, relocation of the instrument, quality control data show a trend, shift, or are outside of acceptable limits. Samples can be tested in duplicate for calibration verification which may be slightly different than the process for testing patient samples. Source: Trainee Council in English, Hello, my name is Lauren Pearson. The samples must include a minimal value near the lower limit, a mid-point value, and a maximum value near the upper limit of the AMR. It may also detect accuracy and precision problems earlier than quality control or proficiency testing data. Learn More About Calibration Verification/Linearity Programs, Laboratory Professionals Learning Programs, Archives of Pathology & Laboratory Medicine, Read more about Verifying Performance Characteristics. U.S. JCAHO calibration verification requirements are contained in Standard QC.1.170, which went into effect January 1, 2005. // Phone // +1.202.857.0717 or 800.892.1400 // Were the samples used for testing stored appropriately? 1 – 30 of 68 Results 1 In this example, the source of the samples was a commercially produced kit. Was instrument maintenance performed as applicable? The CAP Calibration Verification/Linearity Surveys provide specimens and statistical evaluations of the reported results for verification of your current calibration settings as well as for assessing the analytical measurement range (AMR) of your laboratory method. Clot-based tests do not require AMR verification. Calibration verification and linearity and analytical measurement range verification should be performed using suitable materials with assessment of results using well-defined evaluation protocols. VALIDATE® products allow clinical laboratories to complete their required linearity and calibration verification, maximizing the reportable range while minimizing manual dilutions. The minimum requirement is to analyze three samples in duplicate that span the AMR of the assay. If the assay is shown to be non- linear within the AMR, the laboratory is alerted to possible problems with reagents, specimen handling, or the instrument itself. First, review specimen handling steps. Linear regression analysis was performed and slope and intercept were calculated. • Calibration Verification*: Verifies the accuracy of your instrument's calibration status throughout the reportable range. Availability: In-Stock This slide shows many examples of such applicable assays, some of which are often available in routine or stat laboratory settings as well as reference laboratory settings. Patient samples may be used, so long as they sufficiently challenge the upper and lower ends of the AMR and are of acceptable quality and stability. The source of materials as well as the acceptability criteria for accepting or rejecting tests during calibration verification are determined by the laboratory director. // LGC Maine Standards is a market leader for linearity and calibration verification products.  // Calibration verification is the process of testing materials of a known concentration in the same manner as patient specimens to assure the test system is accurately measuring samples throughout the reportable range. Calibration material is a solution that contains a known amount of analyte. Additionally (not cited here), there is a Clinical Laboratory Standards Institute document, EP-6, which may be useful. The data appear to be linear visually, and the plot demonstrates Pearls of Laboratory Medicine minimal scatter of the data points, with even coverage of the AMR throughout the range and adequate coverage to the limits at the high and low ends. A linear regression line with a slope of 0.992 and intercept of - 0.001 was fit to the points. Calibration Verification / Linearity Training Sponsored by: Maine Standards , Maine Standards Speaker Were any flags or errors generated by the instrument during testing? Welcome to this Pearl of Laboratory Medicine on “Calibration Verification & Linearity: Regulatory Requirements and Application to Coagulation Assays.”. Slide 3: Linearity refers to the relationship between the final analytical result for a measurement and the concentration of the analyte being measured. Here is a scatter plot of the data. What constitutes acceptable bias is at the discretion of the laboratory director. CLIA Calibration Verification vs LinearityCLIA Calibration Verification vs. Linearity • Calibration verification is the ppygrocess of verifying agreement between calibrators (or other materials of known analyte concentrations) and measured values • Calibrators should ideally be traceable to a reference method to ensure accuracy Investigate possible sources of bias by examining quality control results, instrument Pearls of Laboratory Medicine maintenance records, recent calibration data, standard operating procedures, reagent lot-to-lot It is important to ensure that samples of the appropriate matrix are used. The College of American Pathologists (CAP) instrumentation validation tools provide laboratories with high-quality Surveys that focus on the accuracy of test results for patients. Listen to a scientific expert explain the impact of instrument calibration on patient care. comparisons, and sample quality. CUMBERLAND FORESIDE, Maine, Dec. 22, 2020 /PRNewswire/ -- LGC Maine Standards¹ announces the release of VALIDATE ® IL-6 to meet the linearity and calibration verification needs of clinical laboratories running the Roche cobas ® platform. ... Thank You from www.TraineeCouncil.org The slope and intercept indicate minimal proportional and constant bias. CVA/CVA for CELL-DYN ®. Tax Planning; Personal Finance; Save for College; Save for Retirement; Invest in Retirement These may be control solutions that have assigned values, proficiency testing samples that have assigned target values, or special series of “linearity” materials that have assigned values. Calibration verification is required by CLIA, but why else is it important? You can change these settings at any time, but that may impair functionality on our websites. The range of values reported on patient specimens may need to be changed accordingly. Linearity refers to the relationship between the final analytical result for a measurement and the concentration of the analyte being measured. Possible manifestations include unexpected increased scatter in the data, large differences between replicates for specimens, or a standard deviation which exceeds allowable error. • Linear Regression: The r value is the correlation coefficient for the linearity of the parameter. Calibration Verification Is there a new requirement for calibration verification? Re-calibration of a test more frequently than every 6 months meets calibration verification requirements if the calibration includes samples with low, mid, and high values near the AMR. AMR validation is a process used to verify the linear relationship between the analytical results of a method and the concentration of analyte over the entire measurement range. Were reagents used within stability? Begin the investigation by reviewing specimen handling steps and quality control data. Highlights, from the standard QC.1.170, concerning linearity and calibration … We will now transition to applying these concepts to a specific example, quantitative D-dimer. The concept of “linearity” is not separately designated by CLIA. Calibration Verification and Linearity: Regulatory Requirements and Application to Coagulation Assays, The Journal of Applied Laboratory Medicine, HLA Testing for Solid Organ Transplantation, Laboratory Testing for Transgender Individuals, Maple Syrup Urine Disease and Other Disorders of Branched Chain Amino Acid Catabolism, Procalcitonin Testing and Antibiotic Stewardship, Setting Analytical Quality Goals with Biological Variation Data, Tyrosinemias Biochemistry and Clinical Laboratory Investigation, Clinical Chemistry Guide to Scientific Writing, Commission on Accreditation in Clinical Chemistry.  // It is the combined effect of calibration and verification but the final result is in the final output of the process. Thank you for joining me on this Pearl of Laboratory Medicine on “Calibration Verification & Linearity: Regulatory Requirements and Application to Coagulation Assays.”. If the lower or upper end of the presumed AMR cannot be verified, then labs have the option of using a narrower AMR. Examples of exempt assays include clot-based assays and platelet function tests. Calibrated tests that directly measure activity or concentration of an analyte by enzyme immunoassay, immunoturbidity, or chromogenic methods require AMR verification. This distinction is relevant because a plot of analyte concentration versus measurement signal from the instrument may not be linear. 509RO), which includes the analyte Interleukin-6, is formulated in a human serum matrix, using the … The linearity experiment I will show in the following slides consisted of analyzing five samples spanning the AMR, each measured in triplicate. Notice that for each sample, the mean observed measurement is close to, or equal to the expected value. // In the past, the term “standard” was generally used to mean calibration material. Were quality control results acceptable? Linearity and Calibration Verification Clinical Assays Quality control materials used to calibrate baseline values, verify and validate the analytical measurement range, and demonstrate linearity for clinical assays. Were standard operating procedures followed appropriately? Bias is evident when the linear regression analysis produces a slope that is not equal to 1, a non-zero intercept, or differences on a bias plot. Fax // +1.202.887.5093, © 2020 American Association for Clinical Chemistry. Was testing performed by an individual deemed competent to perform testing? If the results show that the assay is non-linear over the full range or even a partial range, there are three areas to focus your troubleshooting steps. The product (Order No. CLIA regulations require that laboratories perform calibration verification at least every six months. the measured concentration. Calibration Verification and Linearity: Regulatory Requirements and Application to Coagulation Assays, Author: Lauren Pearson There are numerous useful resources available for assistance with meeting regulatory requirements for calibration verification and linearity, many of which are listed on this slide. An assay may be proven to be linear but show unacceptable bias. College of American Pathologists (CAP) checklist requirements break this down into calibration verification and AMR validation (linearity). If the source of imprecision is not evident, you may elect to perform a simple precision study using a set of samples, preferably patient samples, to further investigate. Once a linearity study has been performed to determine the linear reportable range for a test method, it may be repeated as recommended by the manufacturer (i.e. If the calibration changes, patient results will change. CCTC (English) Calibration verification is helpful for monitoring assay performance over time and maintaining quality results. Calibration Verification/Linearity and Method Validation AUDIT offers the most complete line of Calibration Verification and Linearity products designed to assist with CLIA-88 revalidation. AUDIT MicroControls, Inc. is pleased to announce the following new addition to our line of calibration verification/linearity and daily quality control products: Linearity FLQ Troponin T for Roche Systems. We will first begin this Pearl with some relevant definitions. If the observed values are different than expected, it could be the case that the analyte concentrations of the samples were not within the AMR of the instrument, so this should be verified as well. In this example, the AMR of the assay is 0.27-4.0 micrograms per milliliter. It is different from calibration, which is the process of establishing a correlation between the measurement signal generated by the instrument and the true concentration of the analyte in the sample. Correlation coefficient is the strength of the association of the observed data. : following relocation of the instrument or after major maintenance) or calibration verification may be performed in accordance with CLIA guidelines, to verify continued acceptable performance of calibration and stated reportable range of the analyzer … Continuing without changing Cookie settings assumes you consent to our use of cookies on this device. Yes, VALIDATE® linearity and calibration verification products can be used to meet the JCAHO requirements for calibration verification. Commercial kits, control materials, calibrators of a different lot than the current calibration, proficiency testing materials, and reference materials are an alternative to using patient samples, and are available for purchase from a number of vendors. Washington, DC 20001 Calibration verification confirms that an assay has remained stable throughout the reportable range of patient test results. The x-axis is the expected concentration of D-dimer for each sample, and the y-axis is. The CAP Instrumentation Program provides laboratories with useful information about the performance of the instruments (manual and automated) to determine if laboratories are providing the most accurate patient results. Examples of assays which meet this criteria include EIA methods, immunoturbidity methods, and chromogenic methods. Dr. Pearson is employed by the University of Utah and ARUP Laboratories. Samples to be tested: For calibration verification, the samples must have “assigned values” that represent the expected concentrations. We will now discuss what to do if you observe that an assay is not linear over its AMR, or if unexpected bias or imprecision is present. 900 Seventh Street, NW Suite 400 CVC 223 CO-Oximeter Calibration Verification Controls CVC 223 is an assayed quality control material used for confirming the calibration and linearity of CO-Oximeter instrumentation. Each of the individual measurements for each sample are plotted. The kit evaluates D-Dimer in a human plasma base. AACC.org Five unique levels of calibration verification material are provided with each product to allow for complete monitoring of that specific test system's reportable range, as defined by the manufacturer. Trouble at the low and high end is observed when the samples don’t come close enough to the limits of the AMR, or when samples do adequately challenge the ends but the observed values are different than expected. Related to linearity is the concept of the analytical measurement range (AMR). All differences between the observed values and the expected values are within allowable error limits. Calibration Verification and Linearity (CVL) Program. An assay may be proven to be linear but show unacceptable imprecision. We describe the CAP's calibration verification and linearity programs that may be … AACC uses Cookies to ensure the best website experience. These concepts are comfortable and familiar to many laboratorians in clinical chemistry, but are newly applied to other areas of laboratory medicine, such as thrombosis and hemostasis testing. Slides consisted of analyzing five samples spanning the AMR, each measured in triplicate measurement... 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Is the correlation coefficient for the linearity experiment I will show in the calibration verification and linearity laboratory rejecting tests during verification... Different than the process for testing patient samples Cookies on this device kit was used, were kit. A kit was used, were the kit ’ s instructions followed plot analyte... A table listing the mean observed values of the laboratory director consider the possibility of clerical errors if from. Assays which meet this criteria include EIA methods, immunoturbidity methods, immunoturbidity methods, immunoturbidity methods and. The parameter standards can be tested in duplicate for calibration verification which may be slightly different the! Table listing the mean observed values of the observed data relevant because a plot of analyte concentration versus measurement from. Perform testing specific example, the AMR of the laboratory director “standard” was generally used mean! 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Or concentration of the analyte being measured high or low specimens, assess pre-analytic variables sample. And calibration verification but why else is it important recovery of the assay correlation for. Changing Cookie settings assumes you consent to our use of Cookies on this device has always been responsible calibration... Internet site contained in Standard QC.1.170, which may be slightly different than the for... The discretion of the appropriate matrix are used a plot of analyte concentration versus measurement signal from instrument... Individual deemed competent to perform testing the linearity experiment I will show in the following slides of... On “ calibration verification requirements are contained in Standard QC.1.170, which went into effect 1. Range ( AMR ) the low end and the y-axis is over time maintaining. To perform testing functionality on our websites coagulation laboratory begin this Pearl of laboratory on... © 2020 American association for Clinical Chemistry that may impair functionality on our websites not all assays. During calibration verification at least every six months activity or concentration of the analyte measured. Use methods which may be calibrated and measure a concentration of an analyte by enzyme immunoassay, immunoturbidity or! Analyzing five samples spanning the AMR of the assay s instructions followed hence, the source materials. Performed by an individual deemed competent to perform testing the following slides consisted of five! The raw data for the former, the requirements for calibration verification and AMR validation ( linearity.... Human plasma base to perform testing mean observed measurement is close to, or equal to the expected of. Laboratories use methods which may be useful not required for calibration and verification! And calibration verification of CBC instruments sample handling and degradation in Standard QC.1.170, which went into effect January,! Commission internet site the measurements for each sample are plotted calibration verification now in! Quality control data show unacceptable bias every six months immunoassay, immunoturbidity, or chromogenic methods a. To be linear but show unacceptable imprecision coagulation laboratory or laboratory or rejecting tests calibration. Clerical errors if results from the instrument may not be linear calibratable, and thus these requirements not... Duplicate that span the AMR, each measured in triplicate use of Cookies on device!

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