Biological variation and reference change values of CA 19‐9, CEA, AFP in serum of healthy individuals

Critical review and meta-analysis of biological variation estimates for tumor markers

OBJECTIVES

Biological variation data (BV) can be used for different applications, but this depends on the availability of robust and relevant BV data. In this study, we aimed to summarize and appraise BV studies for tumor markers, to examine the influence of study population characteristics and concentrations on BV estimates and to discuss the applicability of BV data for tumor markers in clinical practice.

METHODS

Studies reporting BV data for tumor markers related to gastrointestinal, prostate, breast, ovarian, haematological, lung, and dermatological cancers were identified by a systematic literature search. Relevant studies were evaluated by the Biological Variation Data Critical Appraisal Checklist (BIVAC) and meta-analyses were performed for BIVAC compliant studies to deliver global estimates of within-subject (CV_I) and between-subject (CV_G) BV with 95% CI.

RESULTS

The systematic review identified 49 studies delivering results for 22 tumor markers; four papers received BIVAC grade A, 3 B, 27 C and 15 D. Out of these, 29 CV_I and 29 CV_G estimates met the criteria to be included in the meta-analysis. Robust data are lacking to conclude on the relationship between BV and different disease states and tumor marker concentrations.

CONCLUSIONS

This review identifies a lack of high-quality BV studies for many tumor markers and a need for delivery of BIVAC compliant studies, including in different, disease states and tumor marker concentrations. As of yet, the state-of-the-art may still be the most appropriate model to establish analytical performance specifications for the majority of tumor markers.

Reference change value and measurement uncertainty in the evaluation of tumor markers

The use of measurement uncertainty among clinical laboratories becomes widespread. Measurement uncertainty can be reported with the result, as well as be used in certain reference change value (RCV) calculation equations. RCV is especially recommended for use in tests with a low individuality index. In our study, we calculated the measurement uncertainty of AFP, CA 125, CA 15-3, CA 19-9, CEA tumor markers with the ISO TS 20914:2019. We compared results with limits. Two Beckman Coulter DXI-800 (Minnesota, USA) autoanalysers' results were used. We calculated the RCV values using the classical Fraser method, logarithmic Lund Method, and Clinical Laboratory Standards Institute (CLSI) method as Minimal Difference (MD). We found the same permissible measurement uncertainty limit as 15.97% for all five tumor markers. The highest RCV value was found as 90% upstream for AFP test with Lund logarithmic approach, the lowest RCV value was found as 12% for CEA with MD, all other RCV results were between these two values. We do not recommend the use of MD, as values for Biological variation are not used in the MD approach. We also recommend using the logarithmic approach, although it gives higher results. There are also clinical studies on the significance of tumor markers in a follow-up that show different results. These differences may be because the studies are conducted with different systems. Therefore, each laboratory needs to calculate its own RCV values. We also recommend informing the clinicians about the tests with high measurement uncertainty.

Within- and between-subject biological variation data for tumor markers based on the European Biological Variation Study

OBJECTIVES

Reliable biological variation (BV) data are required for the clinical use of tumor markers in the diagnosis and monitoring of treatment effects in cancer. The European Biological Variation Study (EuBIVAS) was established by the EFLM Biological Variation Working Group to deliver BV data for clinically important measurands. In this study, EuBIVAS-based BV estimates are provided for cancer antigen (CA) 125, CA 15-3, CA 19-9, carcinoembryonic antigen, cytokeratin-19 fragment, alpha-fetoprotein and human epididymis protein 4.

METHODS

Subjects from five European countries were enrolled in the study, and weekly samples were collected from 91 healthy individuals (53 females and 38 males; 21-69 years old) for 10 consecutive weeks. All samples were analyzed in duplicate within a single run. After excluding outliers and homogeneity analysis, the BVs of tumor markers were determined by CV-ANOVA on trend-corrected data, when relevant (Røraas method).

RESULTS

Marked individuality was found for all tumor markers. CYFRA 21-1 was the measurand with the highest index of individuality (II) at 0.67, whereas CA 19-9 had the lowest II at 0.07. The CV _I s of HE4, CYFRA 21-1, CA 19-9, CA 125 and CA 15-3 of pre- and postmenopausal females were significantly different from each other.

CONCLUSIONS

This study provides updated BV estimates for several tumor markers, and the findings indicate that marked individuality is characteristic. The use of reference change values should be considered when monitoring treatment of patients by means of tumor markers.

Integrated hand-powered centrifugation and paper-based diagnosis with blood-in/answer-out capabilities

To date, 55% of inhabitants of the developing world still live in rural regions and they have a very urgent need to improve the level of disease diagnosis, especially in resource-limited settings. Herein, we present a microfluidic system that centrifuges whole blood and quantifies contained biomarkers in a rapid, feasible and integrated way. Such a device provides a blood-in/answer-out capability and is small enough to be carried by any individual in any environment. The successful integration a hand-powered centrifuge and immunoassay unit within a rotational paper-based device allows for diagnostic application by untrained users and in environments where access to electricity cannot be assumed. In addition, the low cost (~$ 0.5), light weight and small instrumental footprint make the device ideally suited for rapid on-site detection. To validate the applicability of the system in a clinical diagnostic testing, we successfully perform enzyme-linked immunosorbent assay (ELISA) analysis of carcinoembryonic antigen and alpha fetoprotein from human blood samples. We expect that this powerful platform technology will provide the opportunities for point-of-care diagnosis in resource-limited settings.

Development of blood-based biomarker tests for early detection of colorectal neoplasia: Influence of blood collection timing and handling procedures

INTRODUCTION

Blood-based, cancer-associated biomarkers are susceptible to a variety of well-known preanalytical factors. The influence of bowel preparation before a diagnostic colonoscopy on biomarker levels is, however, poorly investigated. The present study assessed the influence of bowel preparation on colorectal cancer-associated biomarkers. In addition, the effect of single versus double centrifugation of plasma biomarkers was assessed.

METHODS

Blood samples were collected pre- and post-bowel preparation from 125 subjects scheduled for first time diagnostic colonoscopy due to symptoms attributable to CRC. The samples were separated into serum and EDTA plasma, and analyzed by four independent collaborators for: 1) the proteins AFP, CA19-9, CEA, hs-CRP, CyFra21-1, Ferritin, Galectin-3 and TIMP-1, 2) the proteins BAG4, IL6ST, vWF, CD44 and EGFR, 3) the glycoprotein Galectin-3 ligand, and 4) cell-free DNA (cfDNA). Statistical analysis of biomarker data has been performed using mixed modelling, including repeated measures.

RESULTS

The biomarkers generally showed negligible variation between pre- and post-bowel preparation except for CyFra21-1, Ferritin, BAG4 and cfDNA. CyFra21-1 levels were systematically reduced with 29% (95% CI 21-36%) by bowel preparation (p ≤ 0.0001). Ferritin was not significantly different between pre- and post-bowel preparation (p = 0.07), however the estimated difference (increase) was 18%. BAG4 was systematically reduced by 12% (95% CI 1-22%, p = 0.04), while cfDNA showed a significant increase of 28% (95% CI 17-39%, p < 0.0001). Double centrifugation compared to single centrifugation showed reduced vWF (ratio 0.86, p ≤ 0.0001) and CD44 (ratio 0.85, p = 0.016), but increased IL6ST levels (ratio 1.18, p = 0.014).

CONCLUSIONS

Results of the present study demonstrated systematic, statistically significant differences between pre-bowel and post-bowel preparation levels for three independent blood-based biomarkers (BAG4, CyFra21-1, cfDNA), illustrating the importance of timing of sample collection for biomarker analyses.

Prediction of survival after left-sided pancreatic resection for adenocarcinoma: Introduction of a new prognostic score

BACKGROUND

Due to the clinically unapparent course the entity of left-sided pancreatic adenocarcinoma is often diagnosed at advanced stages, resulting in small numbers of patients qualifying for pancreatectomy. This study strives to develop a prognostic model for survival after left-sided pancreatic resection.

METHODS

A total of 54 patients were analyzed. Pre- and intra-operative predictive factors for 18-month mortality were identified with multivariable binary logistic regression analysis and compiled into a prognostic model. The applicability was evaluated by assessment of the area under the receiver operating characteristic curve (AUROC). The model was internally validated applying a randomized backwards bootstrapping analysis.

RESULTS

The 18-month mortality rate was 74.1% (n = 40). Mean survival was 19.1 months. A prognostic model for 18-month mortality after left sided-pancreatectomy showed an AUROC >0.800: 18-month mortality risk in% = Exp(Y) / (1 + Exp(Y)) with y= -0.927 + (1.724, if CA 19-9 elevated, otherwise 0) + (1.212 × number of intra-operative transfused packed red blood cells) + (2.771, if prior abdominal surgery, otherwise 0) - (3.612, if gastric resection, otherwise 0) This model was internally validated in 40 randomized backwards bootstrapping steps with AUROCs ranging from 0.757 to 0.971.

CONCLUSIONS

The 18-month mortality risk for patients after left-sided pancreatectomy for adenocarcinoma of the pancreatic body can be assessed with the number of intra-operatively transfused packed red blood cells, elevated CA 19-9 levels, additional gastric resection and prior abdominal surgeries in the patient's history.

Reference intervals for gastrointestinal tumor markers (AFP, CEA, CA199 and CA724) in healthy adults of Han nationality in Chongqing by Roche ECLIA system

The aim of this study is to establish the reference intervals (RIs) for serum gastrointestinal tumor markers (AFP, CEA, CA199 and CA724) in healthy adults of Han nationality in Chongqing by Roche ECLIA system. According to CLSI EP28-A3, the appropriate statistical analysis method was selected and the RIs were determined using the indirect method based on the analysis results. All the test data of the four research projects showed a skewness distribution (p < .05). Gender and age are two important factors influencing the level of detection value. According to the analysis results, the data of the four research projects were grouped by gender and age, and the non-parametric percentile method (95%, double-sided) was used to establish the RIs of each group. The established RIs were validated using the method of Reference Change Value (RCV). The relative deviations between the upper limit value of reference interval in each group of AFP and CEA and that provided by the manufacturer is all smaller than the RCV of eath, so the RIs established by this study is proved to be reliable. While, the relative deviation of the group CEA (male > 40 years old, female > 60 years old) and CA724 is higher than each RCV, which indicates that the RIs provided by the manufacturer is not applicable to the test population and test system of the laboratory. We established RIs of serum gastrointestinal tumor markers (AFP, CEA, CA199 and CA724) in healthy adults of Han nationality in Chongqing by Roche ECLIA system. Furthermore, our study suggests that it is necessary to establish the age-specific and sex-specific RIs for gastrointestinal tumor markers in different detection systems.

Longitudinal analysis of CA19-9 reveals individualised normal range and early changes before development of biliary tract cancer in patients with primary sclerosing cholangitis

BACKGROUND

Primary sclerosing cholangitis is associated with an increased risk of biliary tract cancer. Carbohydrate antigen 19-9 (CA19-9) can be used to screen for these malignancies.

AIM

To perform a longitudinal analysis of CA19-9 in patients with primary sclerosing cholangitis.

METHODS

We conducted a retrospective analysis of CA19-9 values in patients who had primary sclerosing cholangitis, with and without biliary malignancy. We calculated the index of individuality and reference change value in patients who were cancer-free. Long-term analysis of CA19-9 in cancer-free patients was performed and we assessed the change of CA19-9 prior to diagnosis of cancer.

RESULTS

We obtained 1818 CA19-9 values from 247 patients, including 32 with malignancy. Median CA19-9 in cancer-free individuals was 15.6 U/mL. The index of individuality was 0.37 and the reference change value was 46.23%. In cancer-free patients, no significant change in CA19-9 was observed at 1, 2, 5, 7, 10, 15, and 20 years after initial diagnosis of primary sclerosing cholangitis. In patients with biliary tract cancer, CA19-9 was higher at 3 months prior to diagnosis (P < 0.05) than at 6 months before diagnosis and was also higher than at 3 months prior to last follow-up in cancer-free patients (P < 0.05). In 92.9% of patients with biliary cancer, we found an increase in CA19-9 of >46.23% in the year prior to cancer diagnosis.

CONCLUSIONS

CA19-9 in patients with primary sclerosing cholangitis is highly individual, and the reference change value should be preferred to reference intervals. In this study, CA19-9 remained stable in patients who were cancer-free but increased early in those who developed biliary tract cancer. Regular CA19-9 measurement might improve early detection of these malignancies.

Perioperative Serum Carcinoembryonic Antigen Ratio Is a Prognostic Indicator in Patients With Stage II Colorectal Cancer

Purpose

The aim of this study was to evaluate whether the perioperative carcinoembryonic antigen (CEA) ratio could be used as a determinant for adjuvant therapy after curative surgery in stage II colorectal cancer.

Methods

Data for 119 patients with stage II colorectal cancer who underwent radical surgery between 2010 and 2013 were collected. The perioperative CEA ratio was defined as the postoperative/preoperative serum CEA level, and the patients were grouped according to their perioperative CEA ratios: high ratio (≥0.5) and low ratio (<0.5). Overall survival rates were calculated, and their prognostic significances were analyzed.

Results

The overall survival rates of the high and the low perioperative CEA groups were 68.2% and 86.8%, respectively (P = 0.033). In patients with normal preoperative CEA levels (<5 ng/mL), the high perioperative CEA ratio group showed a worse survival rate than the low perioperative CEA ratio group (71.7% vs. 100.0%, P = 0.007). In patients with high preoperative CEA levels (≥5 ng/mL), the high perioperative CEA ratio group showed a worse survival rate than the low perioperative CEA ratio group (33.3% vs. 75.0%, P = 0.036). In the multivariate analysis, perioperative CEA ratio (P = 0.046), age (P = 0.034), and venous invasion (P = 0.015) were independent prognostic factors for survival.

Conclusion

The perioperative CEA ratio is a prognostic indicator for stage II colorectal cancer. Patients with normal preoperative serum CEA levels might also be considered for adjuvant therapy if their perioperative CEA ratios are higher than 0.5.

Serum reference interval of ARCHITECT alpha-fetoprotein in healthy Chinese Han adults: Sub-analysis of a prospective multi-center study

OBJECTIVES

Alpha-fetoprotein (AFP) has been widely used in clinical practice for decades. However, large-scale survey of serum reference interval for ARCHITECT AFP is still absent in Chinese population. This study aimed to measure serum AFP levels in healthy Chinese Han subjects, which is a sub-analysis of an ongoing prospective, cross-sectional, multi-center study (ClinicalTrials.gov Identifier: NCT03047603).

METHODS

This analysis included a total of 530 participants (41.43±12.14years of age on average, 48.49% males), enrolled from 5 regional centers. Serum AFP level was measured by ARCHITECT immunoassay. Statistical analysis was performed using SAS 9.4 and R software.

RESULTS

AFP distribution did not show significant correlation with age or sex. The overall median and interquartile range of AFP was 2.87 (2.09, 3.83) ng/mL. AFP level did not show a trend of increasing with age. The new reference interval was 2.0-7.07ng/mL (LOQ- 97.5th percentiles).

CONCLUSIONS

The reference interval for ARCHITECT AFP is updated with the data of adequate number of healthy Han adults. This new reference interval is more practical and applicable in Chinese adults.

Assessment of average of normals (AON) procedure for outlier-free datasets including qualitative values below limit of detection (LoD): an application within tumor markers such as CA 15-3, CA 125, and CA 19-9

Average of normals (AON) is a quality control procedure that is sensitive only to systematic errors that can occur in an analytical process in which patient test results are used. The aim of this study was to develop an alternative model in order to apply the AON quality control procedure to datasets that include qualitative values below limit of detection (LoD). The reported patient test results for tumor markers, such as CA 15-3, CA 125, and CA 19-9, analyzed by two instruments, were retrieved from the information system over a period of 5 months, using the calibrator and control materials with the same lot numbers. The median as a measure of central tendency and the median absolute deviation (MAD) as a measure of dispersion were used for the complementary model of AON quality control procedure. The u_bias values, which were determined for the bias component of the measurement uncertainty, were partially linked to the percentages of the daily median values of the test results that fall within the control limits. The results for these tumor markers, in which lower limits of reference intervals are not medically important for clinical diagnosis and management, showed that the AON quality control procedure, using the MAD around the median, can be applied for datasets including qualitative values below LoD.

[Persistent elevation of Ca 19-9 and an unexpected finding. A case report]

BACKGROUND

Tumour markers are substances produced by the tumour itself, or by the host in response to a tumour. These markers could be measured either in the blood or in body secretions. One of the most common tumour markers used in gastrointestinal diseases is Ca 19-9. It is the marker most used for pancreatic cancer, but can be elevated in many benign processes. Thus, it is not a specific marker.

CLINICAL CASE

The case is presented of a male patient with 4 years of moderate abdominal pain, weight loss, and persistent elevation of Ca 19-9. After an extensive work-up, renal and hepatic cysts were found, as well as steatosis and, apparently, a gallbladder polyp. With these findings and the persistent elevation of Ca 19-9, it was decided to operate the patient. An exploratory laparoscopy was performed showing multiple, yellowish nodular lesions all over the hepatic surface suggestive of metastases, as well as simple hepatic cysts. Pathology reported biliary hamartomas, steatosis, and chronic cholecystitis. After 2years of follow up, although there is no evidence of malignant neoplasia, there is still an elevation of Ca 19-9.

CONCLUSION

The persistent elevation of Ca 19-9 is probably due to the presence of multiple benign diseases such as steatosis, urolithiasis, hepatic and renal cysts, and cholecystitis. An algorithm is needed for healthy patients with elevated levels of Ca 19-9 marker, in order to lower costs, avoid misdiagnoses, and improve management.

Standardization and quality control in quantifying non-enzymatic oxidative protein modifications in relation to ageing and disease: Why is it important and why is it hard?

Post-translational modifications (PTM) of proteins determine the activity, stability, specificity, transportability and lifespan of a protein. Some PTM are highly specific and regulated involving various enzymatic pathways, but there are other non-enzymatic PTM (nePTM), which occur stochastically, depend on the ternary structure of proteins and can be damaging. It is often observed that inactive and abnormal proteins accumulate in old cells and tissues. The nature, site and extent of nePTM give rise to a population of that specific protein with alterations in structure and function ranging from being fully active to totally inactive molecules. Determination of the type and the amount (abundance) of nePTM is essential for establishing connection between specific protein structure and specific biological role. This article summarizes analytical demands for reliable quantification of nePTM, including requirements for the assay performance, standardization and quality control, and points to the difficulties, uncertainties and un-resolved issues.

Pediatric Population Reference Value Distributions for Cancer Biomarkers and Covariate-Stratified Reference Intervals in the CALIPER Cohort

BACKGROUND

Cancer biomarkers are commonly used in pediatrics to monitor cancer progression, recurrence, and prognosis, but pediatric reference value distributions have not been well established for these markers. The Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) sought to develop a pediatric database of covariate-stratified reference value distributions for 11 key circulating tumor markers, including those used in assessment of patients with childhood or adult cancers.

METHODS

Healthy community children from birth to 18 years of age were recruited to participate in the CALIPER project with informed parental consent. We analyzed serum samples from 400–700 children (depending on the analyte in question) on the Abbott Architect ci4100 and established reference intervals for α-fetoprotein (AFP), antithyroglobulin (anti-Tg), human epididymis protein 4 (HE4), cancer antigen 125 (CA125), CA15-3, CA19-9, progastrin-releasing peptide (proGRP), carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCC), and total and free prostate specific antigen (PSA) according to CLSI C28-A3 statistical guidelines.

RESULTS

We observed significant fluctuations in biomarker concentrations by age and/or sex in 10 of 11 biomarkers investigated. Age partitioning was required for CA153, CA125, CA19-9, CEA, SCC, proGRP, total and free PSA, HE4, and AFP, whereas sex partitioning was also required for CA125, CA19-9, and total and free PSA.

CONCLUSIONS

This CALIPER study established a database of childhood reference intervals for 11 tumor biomarkers and revealed dramatic fluctuations in tumor marker concentrations between boys and girls and throughout childhood. In addition, important differences between the adult and pediatric population were observed, further highlighting the need for pediatric-specific reference intervals.

Pediatric Within-Day Biological Variation and Quality Specifications for 38 Biochemical Markers in the CALIPER Cohort

BACKGROUND

Studies of biological variation provide insight into the physiological changes that occur within and between study participants. Values obtained from such investigations are important for patient monitoring and for establishing quality specifications. In this study we evaluated the short-term biological variation of 38 chemistry, lipid, enzyme, and protein analytes in a pediatric population, assessed the effect of age partitions on interindividual variation, and compared the findings to adult values.

METHODS

Four plasma samples each were obtained within 8 h from 29 healthy children (45% males), age 4–18 years. Samples were stored at −80 °C and analyzed in 3 batches, with samples from 9–10 study participants per batch. Within-person and between-person biological variation values were established using nested ANOVA after exclusion of outliers by use of the Tukey outlier test. Analytical quality specifications were established with the Fraser method.

RESULTS

Biological variation coefficients and analytical goals were established for 38 analytes. Age partitioning was required for 6 analytes. Biological variation characteristics of 14 assays (37%) were distinct from adult values found in the Westgard database on biological variation. Biological variation characteristics were established for 2 previously unreported analytes, unconjugated bilirubin and soluble transferrin receptor.

CONCLUSIONS

This study is the first to examine biological variation and to establish analytical quality specifications on the basis of biological variation for common assays in a pediatric population. These results provide insight into pediatric physiology, are of use for reference change value calculations, clarify the appropriateness of reference interval use, and aid in the development of quality management strategies specific to pediatric laboratories.

[Variability of healthy human proteome]

The purpose of this review is to analyze investigations devoted to characteristic of protein variability and diversity of their posttranslational modifications in healthy humans. The numerous researches have demonstrated that proteomic profile has a considerable both intra- and inter-individual variability, and quite often normal variability of some proteins can be comparable to changes observed in pathological processes. Results obtained by our research group have confirmed high intra-individual variability of serum low-molecular subproteome of healthy volunteers, certified by a special medial committee. Proteins characterized by high variability in normal conditions (e.g. haptoglobin--0-40 mg/ml; lysozyme--0,01-0,1 mg/ml; C-reactive protein--0,01-0,3 mg/ml) should be excluded from the list of potential biomarkers. On the contrary, proteins and peptides characterized by insignificant dispersion in healthy population (such as albumin--coefficient of variation (CV) 9%; transferrin--CV14%; C3c complement--CV 17%, alpha-1 acid glycoprotein--CV 21%, alpha2-macroglobulin--CV 20%; transthyretin fragment--CV 28,3% and beta-chain alpha2-HS-glycoprotein--CV 29,7%) can provide us with important information about state of health. Thus investigations of plasticity in proteomic profiles of healthy humans will help to correct reference intervals used in clinical proteomics.

The pitfalls of CA19-9: routine testing and comparison of two automated immunoassays in a reference oncology center

We evaluated CA19-9 as a marker of various malignancies and compared the results of 2 commercial immunoassays. The Abbott ARCHITECT i2000 and Roche cobas 410 immunoassays were used on 500 consecutive samples to evaluate the frequency of positive results by cancer type and the correlation between assays. The patients were tested before or after surgery and/or during chemotherapy. The rate of results exceeding conventional thresholds was 92.3% in pancreatic cancer, 36.8% in gastric cancer, and ranged from 3.0% to 35.9% in other tumors. Agreement (90.6%) and correlation (R(2) = 0.865) between the 2 assays were good and the frequency of highly discordant results was low (6/500). In some cases, interference by heterophilic antibodies was demonstrated. The 2 methods were comparable in diagnostic accuracy and had good correlation but are not interchangeable. Patients should always be monitored for CA19-9 with the same method and it should be indicated in the report.

Reference intervals for serum alpha-fetoprotein and carcinoembryonic antigen in Chinese Han ethnic males from the Fangchenggang Area Male Health and Examination Survey

OBJECTIVES

We calculated upper 95% reference limits for serum alpha-fetoprotein (AFP) and carcinoembryonic antigen (CEA) according to the CLSI/NCCLS C28-A3 guideline.

MATERIAL AND METHODS

Serum samples from 1400 healthy male subjects were collected from the Fangchenggang Area Male Health and Examination Survey (FAMHES). Serum AFP and CEA values were measured by electrochemiluminescence immunoassay on COBAS 6000 system E601 (Elecsys module) immunoassay analyzers.

RESULTS

Serum AFP and CEA values were not normally distributed but log normally distributed. The upper 95% reference limits of the reference intervals were ≤ 4.76 IU/mL (nonparametric) or ≤ 4.56 IU/mL (parametric) for AFP and ≤ 5.57 ng/mL (nonparametric) or ≤ 5.82 ng/mL (parametric) for CEA. The distribution of AFP levels was found to be consistent between the non-smoking and smoking (p=0.740) and non-drinking and drinking groups (p=0.698). The distribution of serum CEA levels was significantly higher in the smoking than the non-smoking group (p<10⁵), whereas there was no significant difference in this respect between the non-drinking and drinking groups (p=0.147). A significant increase with age was found both for serum AFP and CEA levels, and the age-dependent reference intervals were calculated.

CONCLUSIONS

The reference intervals for serum AFP and CEA show a slight deviation compared to previously reported reference levels. Distinct reference intervals of serum CEA must be established for smoking and non-smoking populations. In addition, age-dependent reference intervals should be implemented in clinical laboratories.

Analytical performance and clinical concordance of the cancer biomarkers CA 15-3, CA 19-9, CA 125 II, Carcinoembryonic Antigen, and Alpha-Fetoprotein on the Dimension Vista® System

OBJECTIVES

We examined analytical characteristics of new CA 15-3, CA 19-9, CA 125 II, Carcinoembryonic Antigen (CEA), and Alpha-Fetoprotein (AFP) assays on the Dimension Vista® System.

DESIGN AND METHODS

Imprecision studies used CLSI-EP5-A2, Limit of Blank and Limit of Detection used CLSI-EP17 and measurement ranges were determined. Method comparisons were evaluated with Passing-Bablok, least-squares regression and residual plots. Reference intervals were determined and valid specimen types, lot-to-lot variability and sample storage stability were defined. Clinical monitoring patterns for each tumor marker in patients were examined.

RESULTS

Reproducibility for each method was <6.5%. Limits of Blank and Detection were low. Comparisons between methods showed slopes ranging from 0.89 to 1.32 with low y-intercepts and scatter. Minimal lot-to-lot variability was documented; serum/plasma specimens provide valid results; sample stability at -70°C was >9months. Clinical monitoring patterns correlated with established methods in >89% of cases.

CONCLUSIONS

Measurement of CA 15-3, CA 19-9, CA 125 II, CEA and AFP on the Dimension Vista® System is an attractive alternative.