SUPERIOR SAMPLES. ACCURATE RESULTS.
Our human serum samples are the foundation of our accuracy assessment tools. They are commutable, free of additives and stabilizers, and each is assigned a target value using one of our credentialed reference methods or other means of verification. Only by meeting these strict criteria can they reliably assess the ‘trueness’ of a given test. This allows for better medical decision-making and, ultimately, better health outcomes.
CEQAL samples cover a wide range of clinical applications. To highlight a clinical category use the filter below. Select an individual sample to see the methods we use to assign target values.
CLINICAL CATEGORY:
-
- Total Cholesterol
- HDL Cholesterol
- LDL Cholesterol
- Total & Net Triglyceride
- Apoprotein
A-1 & B - Glucose
Total Cholesterol
CLINICAL APPLICATIONS
Cardiovascular Risk Assessment, Diabetes Management
HOW TARGET VALUES ARE ASSIGNED:
This reference method is based upon the Abell, Levy, Brodie and Kendall method as modified by the Centers for Disease Control and Prevention. The method and materials have been credentialed and approved by the National Reference System for the Clinical Laboratory, Clinical and Laboratory Standards Institute (Document RS3-A).
Abell LL, Levy BB, Brodie RB, Kendall RB. Simplified method for the estimation of total cholesterol in serum and demonstration of its specificity. J Biol Chem 1952;195:357-366.
Duncan IW, Mather A, Cooper GR. The procedure for the proposed cholesterol reference method. Atlanta, GA: Centers for Disease Control and Prevention, 1982.
HDL Cholesterol
CLINICAL APPLICATIONS
Cardiovascular Risk Assessment, Diabetes Management
HOW TARGET VALUES ARE ASSIGNED:
This reference method measures high-density lipoprotein cholesterol after first removing very low-density lipoproteins and chylomicrons by ultracentrifugation. Subsequently low-density lipoproprotein cholesterol is precipitated by heparin manganese and the cholesterol in the supernatant is then quantified by the Abell-Kendall cholesterol reference method. This method is traceable to the Centers for Disease Control and Prevention high-density lipoprotein cholesterol ultracentrifuge reference method.
Hainline A, Karon J, Lippel K eds. Manual of laboratory operations. In: Lipid Research Clinics Program, Lipid and lipoprotein analysis, 2nd ed. US Department of Health and Human Resources, Bethesda, MD.1982.
This method uses dextran sulphate (molecular weight 50,000 Daltons) as a precipitant. All lipoproteins except high-density lipoprotein cholesterol are precipitated. High-density lipoprotein cholesterol in the supernatant is measured by the Abell-Kendall cholesterol reference method. This method is traceable to the Centers for Disease Control and Prevention high-density lipoprotein cholesterol ultracentrifugation reference method. Traceability is limited by the triglyceride concentration of the sample. However, due to the large volume requirements of the Ultracentrifugation method, the DCM is often used for manufacturer’s certification of HDL.
Kimberly MM, Leary ET, Cole TG, Waymack PP for the Cholesterol Reference Method Laboratory Network. Selection, validation, standardization, and performance of a designated comparison method for HDL-cholesterol for use in the Cholesterol Reference Method Laboratory Network. Clin Chem 1999, 45:1803-1812.
LDL Cholesterol
CLINICAL APPLICATIONS
Cardiovascular Risk Assessment, Diabetes Management
HOW TARGET VALUES ARE ASSIGNED:
Beta-Quantification
Low-density lipoprotein cholesterol is measured after ultracentrifugation for high-density lipoprotein cholesterol. The cholesterol content of the infranate (which contains both LDL and HDL cholesterol) is measured and the low-density lipoprotein cholesterol content is calculated as the difference after high-density lipoprotein cholesterol has been determined. This method is traceable to the Centers for Disease Control and Prevention Beta-quantification reference method.
Hainline A, Karon J, Lippel K eds. Manual of laboratory operations. In: Lipid Research Clinics Program, Lipid and lipoprotein analysis, 2nd ed. US Department of Health and Human Resources, Bethesda, MD.1982.
Total & Net Triglyceride
CLINICAL APPLICATIONS
Cardiovascular Risk Assessment, Diabetes Management, Evaluation of Liver Function
HOW TARGET VALUES ARE ASSIGNED:
Total triglycerides and free glycerol are determined using a two-step glycerol phosphate oxidase (GPO) reaction, with and without lipase. Net triglycerides are calculated as the difference between total triglyceride and free glycerol. Calibration is traceable to the CDC reference method.
Klotzsch SG, McNamara JR. Clin Chem 1990:36:1605-13
The CDC has replaced the reference method with GC-IDMS analysis of Total Glycerides. CEQAL can provide calibration traceability to both methodologies.
Apoprotein A-1 & B
CLINICAL APPLICATIONS
Cardiovascular Risk Assessment, Diabetes Management
HOW TARGET VALUES ARE ASSIGNED:
This nephelometric method is calibrated using calibration materials that are traceable to the World Health Organization reference material SP1-01 for apolipoprotein A-1 and SP3-07 for apolipoprotein B. The methods have been standardized according to the standardization protocol as detailed by Marcovina et al. Ongoing performance is monitored through an internal quality assessment program with values assigned against the WHO/IFCC reference materials.
Marcovina SM, Albers JJ, Henderson LO, Hannon WH. International Federation of Clinical Chemistry standardization project for measurement of apolipoproteins. III Comparability of apo A-1 values by use of common reference material. Clin Chem 1993;39:773-778.
Marcovina SM, Albers JJ, Kennedy H et al. International Federation of Clinical Chemistry standardization project for measurement of apolipoproteins A-1 and B. IV: Comparability of apo B values using international reference materials. Clin Chem 1994;40:586-592
Glucose
CLINICAL APPLICATIONS
Diabetes Management, Cardiovascular Risk Assessment
HOW TARGET VALUES ARE ASSIGNED:
This reference method is based upon the hexokinase/glucose-6-phosphate dehydrogenase method as developed by the Glucose Committee of the American Association for Clinical Chemistry and the Centers for Disease Control and Prevention. The method and materials have been credentialed and approved by the National Reference System for the Clinical Laboratory, Clinical and Laboratory Standards Institute (Document RS1-A).
Neese JW, Duncan P, Bayse DD et al. Development and evaluation of a hexokinase/glucose-6-phosphate dehydrogenase procedure for use as a national glucose reference method. HEW Publication No. (CDC) 77-8330. HEW. USPHS, Centers for Disease Control and Prevention, 1976.
Neese JW, Duncan P, Bayse DD et al. Development and evaluation of a hexokinase/glucose-6-phosphate dehydrogenase procedure for use as a national glucose reference method. Clin Chem 1974;20:878.
-
HbA1c
CLINICAL APPLICATIONS
Diabetes Management
HOW TARGET VALUES ARE ASSIGNED:
Glycated hemoglobin (HbA1c) has target values assigned by the Diabetes Diagnostic Laboratory at the University of Missouri, which served as the Reference Laboratory for the measurement of HbA1c in the Diabetes Control and Complications Trial (DCCT). The method employed is now a Secondary Reference Laboratory (SRL) method in the National Glycohemoglobin Standardization Program (NGSP) network.
The Diabetes Control and Complications Research Group: The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med 1993: 29:977-986.
UREA
CLINICAL APPLICATIONS
Evaluation of Renal Function
HOW TARGET VALUES ARE ASSIGNED:
This reference method is based upon the coupled enzyme reaction of urease and glutamate dehydrogenase. The method was developed, validated and tested for its transferability. The method and materials have been credentialed and approved by the National Reference System for the Clinical Laboratory, Clinical and Laboratory Standards Institute (Document RS11-P). Blood urea nitrogen (BUN) may be calculated from the urea result.
Sampson EJ et al. A coupled-enzyme equilibrium method for measuring urea in serum: optimization and evaluation of the AACC study group on urea candidate reference method. Clin Chem 1980; 26:816-826.
Creatinine
CLINICAL APPLICATIONS
Evaluation of Renal Function
HOW TARGET VALUES ARE ASSIGNED:
Creatinine is measured in human serum using a JCTLM-listed isotope dilution gas chromatograph mass spectrometry methodology (NRMeth 1) as carried out in collaboration with Dr. L Thienpont’s laboratory at the University of Gent, Belgium. The method is used for certification of the CRMs for creatinine from BCR (European Commission).
Joint Committee for Traceability in Laboratory Medicine (JCTLM). Database for higher-order reference materials, measurement methods/procedures and services. http://www.bipm.org/jctlm/
Urine Albumin
CLINICAL APPLICATIONS
Evaluation of Renal Function
HOW TARGET VALUES ARE ASSIGNED:
Human urine samples are augmented gravimetrically with human serum albumin to generate samples covering the clinical range of interest for albumin and ACR (albumin:creatinine ratio). These augmented urine pools have been shown to be commutable as assessed relative to an LC-MS/MS comparative method. To date there are no credentialed reference methods for the measurement of albumin in urine.
Jacobson BE, Seccombe DW, Levin, A. A study examining the accuracy of albumin and ACR measurements in urine.
Sodium
CLINICAL APPLICATIONS
Evaluation of Renal Function, Electrolyte Balance
HOW TARGET VALUES ARE ASSIGNED:
This reference method is based upon the flame atomic emission spectrometry method for measuring sodium in serum as developed cooperatively by the National Institute of Standards and Technology and the Centers for Disease Control and Prevention. The method and materials have been credentialed and approved by the National Reference System for the Clinical Laboratory, Clinical and Laboratory Standards Institute (Document RS7-P).
Velapoldi RA, Paul RC, Schaffer R et al. A reference method for the determination of sodium in serum. NBS special publication 260-60. US Department of Commerce/National Bureau of Standards, Washington, DC 1978.
Potassium
CLINICAL APPLICATIONS
Evaluation of Renal Function, Electrolyte Balance
HOW TARGET VALUES ARE ASSIGNED:
This reference method is based upon the flame atomic emission spectrometry method for measuring potassium in serum as developed cooperatively by the National Institute of Standards and Technology and the Centers for Disease Control and Prevention. The method and materials have been credentialed and approved by the National Reference System for the Clinical Laboratory, Clinical and Laboratory Standards Institute (Document RS8-P).
Velapoldi RA, Paul RC, Schaffer R et al. A reference method for the determination of potassium in serum. NBS special publication 260-63. US Department of Commerce/National Bureau of Standards, Washington, DC 1978. 2nd ed. US Department of Health and Human Resources, Bethesda, MD.1982.
-
Chloride
CLINICAL APPLICATIONS
Evaluation of Renal Function, Electrolyte Balance
HOW TARGET VALUES ARE ASSIGNED:
This reference method is based upon the coulometric generation of silver ions and the amperometric indication of the endpoint (Cotlove method). The method and materials have been credentialed and approved by the National Reference System for the Clinical Laboratory, Clinical and Laboratory Standards Institute (Document RS10-P).
Velapoldi RA, Paule RC, Schaffer R et al. A reference method for the determination of chloride in serum. NBS special publication 260-67. US Department of Commerce/National Bureau of Standards, Washington, DC 1979.
Total Protein
CLINICAL APPLICATIONS
Evaluation of Liver Function
HOW TARGET VALUES ARE ASSIGNED:
This reference method is based upon the biuret reaction as developed, validated and tested for transferability by Doumas et al. The method and materials have been credentialed and approved by the National Reference System for the Clinical Laboratory, National Committee for Clinical Laboratory Standards (Document RS5-A2).
Doumas BT, Bayse DD, Carter RJ et al. A candidate reference method for determination of total protein in serum. I. Development and validation. Clin Chem 1981;27:1642-1650.
Doumas BT, Bayse DD, Carter RJ et al. A candidate reference method for determination of total protein in serum. II. Test for transferability. Clin Chem 1981;27:1651-1654.
Total Bilirubin
CLINICAL APPLICATIONS
Evaluation of Liver Function
HOW TARGET VALUES ARE ASSIGNED:
This reference method is based upon the Jendrassik-Grof principle as developed by Doumas et al. The method and materials have been credentialed and approved by the National Reference System for the Clinical Laboratory, National Committee for Clinical Laboratory Standards (Document RS6-A).
Doumas BT, Perry BW, Bayse DD et al. A candidate reference method for the determination of bilirubin in serum, test for transferability. Clin Chem 1983; 29:297-301.
Doumas BT, Kwok-Cheung PP, Perry BW et al. Candidate reference method for determination of total bilirubin in serum: development and validation. Clin Chem 1985;21:1779-1789.
Direct Bilirubin
CLINICAL APPLICATIONS
Evaluation of Liver Function
HOW TARGET VALUES ARE ASSIGNED:
The Direct Bilirubin method is a modification of the Doumas reference method for Total Bilirubin. In an acidic medium bilirubin conjugates and delta bilirubin are known to react with Diazo Reagent. Ascorbic acid is added to the reaction to block unconjugated bilirubin from reacting with the Diazo Reagent. Absorbance of the azobilirubin formed is monitored at 598 nm.
Doumas BT, Perry BW, Bayse DD et al. A candidate reference method for the determination of bilirubin in serum, test for transferability. Clin Chem 1983; 29:297-301.
Doumas BT, Kwok-Cheung PP, Perry BW et al. Candidate reference method for determination of total bilirubin in serum: development and validation. Clin Chem 1985;21:1779-1789.
Alkaline Phosphatase
CLINICAL APPLICATIONS
Evaluation of Liver Function
HOW TARGET VALUES ARE ASSIGNED:
The catalytic activity concentration of ALP is assigned by the JCTLM listed IFCC reference method C7RMP2R as operated in Prof. Dr. G. Schumann’s laboratory at the DGKL Reference Institute of Bioanalysis, Hannover Germany.
Joint Committee for Traceability in Laboratory Medicine (JCTLM). Database for higher-order reference materials, measurement methods/procedures and services. http://www.bipm.org/jctlm/
Aspartate Aminotransferase
CLINICAL APPLICATIONS
Evaluation of Liver Function
HOW TARGET VALUES ARE ASSIGNED:
The catalytic activity concentration of AST is assigned by the JCTLM listed IFCC primary reference method NRMeth 68 as operated in Prof. Dr. G. Schumann’s laboratory at the DGKL Reference Institute of Bioanalysis, Hannover Germany.
Joint Committee for Traceability in Laboratory Medicine (JCTLM). Database for higher-order reference materials, measurement methods/procedures and services. http://www.bipm.org/jctlm/
-
Alanine Transaminase
CLINICAL APPLICATIONS
Evaluation of Liver Function
HOW TARGET VALUES ARE ASSIGNED:
The catalytic activity concentration of ALT is assigned by the JCTLM listed IFCC primary reference method NRMeth 67 as operated in Prof. Dr. G. Schumann’s laboratory at the DGKL Reference Institute of Bioanalysis, Hannover Germany.
Joint Committee for Traceability in Laboratory Medicine (JCTLM). Database for higher-order reference materials, measurement methods/procedures and services. http://www.bipm.org/jctlm/
Gamma-glutamyl transferase
CLINICAL APPLICATIONS
Evaluation of Liver Function
HOW TARGET VALUES ARE ASSIGNED:
The catalytic activity concentration of GGT is assigned by the JCTLM listed IFCC primary reference method NRMeth 69 as operated in Prof. Dr. G. Schumann’s laboratory at the DGKL Reference Institute of Bioanalysis, Hannover Germany.
Joint Committee for Traceability in Laboratory Medicine (JCTLM). Database for higher-order reference materials, measurement methods/procedures and services. http://www.bipm.org/jctlm/
Fecal Occult Blood
CLINICAL APPLICATIONS
Colon Cancer Screening
HOW TARGET VALUES ARE ASSIGNED:
The sample matrix for this product has been formulated to simulate human feces with known concentrations of human hemoglobin per gram wet weight. The hemoglobin concentration of the spiking concentrate has been validated using the CLSI H15-A3 reference method for the quantitative determination of hemoglobin as calibrated against the NIBSC – WHO Haemiglobincyanide Reference Standard.
Reference and Selected Procedures for the Quantitative Determination of Hemoglobin in Blood; Approved Standard - Third Edition CLSI H15-A3 Vol.20 No.28
HIV-1
CLINICAL APPLICATIONS
HIV Screening
HOW TARGET VALUES ARE ASSIGNED:
Qualitative serum samples containing human IgG levels that are optimized for INSTI™ HIV antibody test are prepared to yield negative, weak positive and strong positive results when tested following the assay procedures outlined for INSTI™
Note: These samples were customized for bioLytical Laboratories and their INSTI™ HIV test. However, similar quality control samples can be produced for other HIV testing methods or screening programs.
Human Serum Lipid Pools
CEQAL can provide pools of human serum with normal and abnormal concentrations of lipids that are customized to your requirements. As a member of the CRMLN, we use our credentialed reference methods to assign target values for total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, apoproteins B and A-1. These samples may be used to confirm the linearity of your lipid testing methods and accuracy of your lipid test results. Use these pools to establish accuracy-based internal quality control programs, achieve harmonization of lipid testing within networks of clinical labs, or document traceability of your methods to a defined base of accuracy.
Human Serum Chemistry Pools
CEQAL uses a proprietary dialysis and augmentation process for producing pools of human serum with varying concentrations of analytes covering the clinical range of interest. Only purified human enzymes and proteins are used for augmentation purposes. The samples are sterilized by (0.2µm) filtration and are free of additives and stabilizers. Selected analytes have target values assigned by credentialed reference methods. The commutable matrix sample sets enable you to improve the quality of your systems for monitoring accuracy, linearity and precision. These samples may also be used for harmonization of testing within networks of clinical labs.
-
Individual Donor Serum
The only sample matrix that can be used to confirm the accuracy of lipid testing is human serum, without augmentation, additives, or stabilizers. CEQAL conducts several clinics annually to collect samples from both normal and dyslipidemic donors. We can, therefore, supply individual lipid donor serum samples that cover the clinical range of interest for lipid measurements and meet your specific accuracy assessment needs.
Sample Procurement
Upon request, CEQAL can source individual patient samples covering the clinical range of interest for a particular analyte. These samples may be used in developing new testing methods, in transferring a method from one instrument to another, or in the performance assessment of an existing method. Contact us for more information.
Target Value Assignment
The calibration materials used by instrument manufacturers are typically not commutable and thus cannot be relied upon to accurately set calibration values. Using our reference methods, we can assign target values to samples used in a manufacturer’s calibration process. CEQAL can also confirm the transferability of these values by providing individual donor serum samples with reference-assigned target values.
Customized Samples
If you are searching for an analyte not featured on our menu, CEQAL can create customized accuracy-based samples to suit your purposes. The fecal occult blood samples, for instance, were originally developed for the Ontario Association of Medical Laboratories (OAML) and are still being used in their External Quality Assessment [EQA] and Internal Quality Control [IQC] programs.
We can also produce customized preparations of human serum chemistry pools to examine possible interferences between analytes. CEQAL can produce sample sets with identical concentrations of one analyte and variable concentration of a second analyte. This enables you to determine if elevated concentrations of the second analyte interferes with the accurate analysis of the first.
Contact us to discuss your specific requirements.
CDC Certificate of Traceability available