Investigating the Current Harmonization Status of Tumor Markers Using Global External Quality Assessment Programs: A Feasibility Study.

BACKGROUND: The harmonization status of most tumor markers (TMs) is unknown. We report a feasibility study performed to determine whether external quality assessment (EQA) programs can be used to obtain insights into the current harmonization status of the tumor markers α-fetoprotein (AFP), prostate specific antigen (PSA), carcinoembryonic antigen (CEA), cancer antigen (CA)125, CA15-3 and CA19-9. METHODS: EQA sample results provided by 6 EQA providers (INSTAND [Germany], Korean Association of External Quality Assessment Service [KEQAS, South Korea], National Center for Clinical Laboratories [NCCL, China], United Kingdom National External Quality Assessment Service [UK NEQAS, United Kingdom], Stichting Kwaliteitsbewaking Medische Laboratoriumdiagnostiek [SKML, the Netherlands], and the Royal College of Pathologists of Australasia Quality Assurance Programs [RCPAQAP, Australia]) between 2020 and 2021 were used. The consensus means, calculated from the measurement procedures present in all EQA programs (Abbott Alinity, Beckman Coulter DxI, Roche Cobas, and Siemens Atellica), was used as reference values. Per measurement procedure, the relative difference between consensus mean for each EQA sample and the mean of all patient-pool-based EQA samples were calculated and compared to minimum, desirable, and optimal allowable bias criteria based on biological variation. RESULTS: Between 19040 (CA15-3) and 25398 (PSA) individual results and 56 (PSA) to 76 (AFP) unique EQA samples were included in the final analysis. The mean differences with the consensus mean of patient-pool-based EQA samples for all measurement procedures were within the optimum bias criterion for AFP, the desirable bias for PSA, and the minimum bias criterion for CEA. However, CEA results <8 µg/L exceeded the minimum bias criterion. For CA125, CA15-3, and CA19-9, the harmonization status was outside the minimum bias criterion, with systematic differences identified. CONCLUSIONS: This study provides relevant information about the current harmonization status of 6 tumor markers. A pilot harmonization investigation for CEA, CA125, CA15-3, and CA19-9 would be desirable.

Recommendations for validation testing of home pregnancy tests (HPTs) in Europe.

Home pregnancy tests (HPTs) available in Europe include accuracy and other performance claims listed on their packaging. Due to the lack of guidance on the standardisation of such products, it is often difficult to replicate these claims when tested on a clinical sample, whether in a laboratory setting or by lay users. The In Vitro Diagnostic Regulation is a set of requirements that mandate comprehensive validation data on human pregnancy tests and other in vitro devices. It is due to replace the current European Directive (98/79/EC) and fully implemented in Europe by 2022. In June 2019, a panel of seven experts convened to discuss the validation studies required to provide the information needed to meet the new regulation for HPTs in Europe and proposed 15 recommendations for best practice. Defining best practice at all stages of validation of these important tests may ensure that tests marketed in Europe are fit for purpose, enabling lay users to be confident of the high quality of the HPT results they obtain. The panelists believe that the recommendations proposed here for the validation of HPTs may constructively contribute to improved standardisation of validation procedures in Europe.

Clinical Use of Cancer Biomarkers in Epithelial Ovarian Cancer: Updated Guidelines From the European Group on Tumor Markers.

OBJECTIVE: To present an update of the European Group on Tumor Markers guidelines for serum markers in epithelial ovarian cancer. METHODS: Systematic literature survey from 2008 to 2013. The articles were evaluated by level of evidence and strength of recommendation. RESULTS: Because of its low sensitivity (50-62% for early stage epithelial ovarian cancer) and limited specificity (94-98.5%), cancer antigen (CA) 125 (CA125) is not recommended as a screening test in asymptomatic women. The Risk of Malignancy Index, which includes CA125, transvaginal ultrasound, and menopausal status, is recommended for the differential diagnosis of a pelvic mass. Because human epididymis protein 4 has been reported to have superior specificity to CA125, especially in premenopausal women, it may be considered either alone or as part of the risk of ovarian malignancy algorithm, in the differential diagnosis of pelvic masses, especially in such women. CA125 should be used to monitor response to first-line chemotherapy using the previously published criteria of the Gynecological Cancer Intergroup, that is, at least a 50% reduction of a pretreatment sample of 70 kU/L or greater. The value of CA125 in posttherapy surveillance is less clear. Although a prospective randomized trial concluded that early administration of chemotherapy based on increasing CA125 levels had no effect on survival, European Group on Tumor Markers state that monitoring with CA125 in this situation should occur, especially if the patient is a candidate for secondary cytoreductive surgery. CONCLUSIONS: At present, CA125 remains the most important biomarker for epithelial ovarian cancer, excluding tumors of mucinous origin.

Validation of new cancer biomarkers: a position statement from the European group on tumor markers.

BACKGROUND: Biomarkers are playing increasingly important roles in the detection and management of patients with cancer. Despite an enormous number of publications on cancer biomarkers, few of these biomarkers are in widespread clinical use. CONTENT: In this review, we discuss the key steps in advancing a newly discovered cancer candidate biomarker from pilot studies to clinical application. Four main steps are necessary for a biomarker to reach the clinic: analytical validation of the biomarker assay, clinical validation of the biomarker test, demonstration of clinical value from performance of the biomarker test, and regulatory approval. In addition to these 4 steps, all biomarker studies should be reported in a detailed and transparent manner, using previously published checklists and guidelines. Finally, all biomarker studies relating to demonstration of clinical value should be registered before initiation of the study. SUMMARY: Application of the methodology outlined above should result in a more efficient and effective approach to the development of cancer biomarkers as well as the reporting of cancer biomarker studies. With rigorous application, all stakeholders, and especially patients, would be expected to benefit.

Gaps in the traceability chain of human growth hormone measurements.

BACKGROUND: Human growth hormone (hGH) is measured for the diagnosis of secretion disorders. These measurements fall under the EU Directive 98/79/EC on in vitro diagnostic medical devices requiring traceability of commercial calibrator values to higher-order reference materials or procedures (Off J Eur Communities 1998 Dec 7;L 331:1-37). External quality assessment schemes show large discrepancies between results from different methods, even though most methods provide results traceable to the recommended International Standard (IS 98/574). The aim of this study was to investigate possible causes for these discrepancies. METHODS: We investigated the commutability and recovery of hGH in reconstituted IS 98/574. We tested different reconstitution protocols and used 4 different serum matrices for spiking. These IS preparations were measured together with serum samples. We quantified hGH by 5 different methods in 4 different laboratories. RESULTS: Results from the different methods correlated well for the serum samples. Mean discrepancies between results from different methods were ≤20%. None of the IS preparations was commutable for all the method comparisons. The recovery of hGH in preparations of IS 98/574 depended on the reconstitution protocol (>10-fold differences) and background matrix (relative differences ≤17% for different serum matrices). CONCLUSIONS: The use of different protocols for reconstitution and spiking of hGH reference preparations affects quantification by immunoassays, potentially leading to a bias between commercial methods, despite the use of calibrators with values claimed to be traceable to the same higher-order reference material.

Design of tumor biomarker-monitoring trials: a proposal by the European Group on Tumor Markers.

A major application of tumor biomarkers is in serial monitoring of cancer patients, but there are no published guidelines on how to evaluate biomarkers for this purpose. The European Group on Tumor Markers has convened a multidisciplinary panel of scientists to develop guidance on the design of such monitoring trials. The panel proposes a 4-phase model for biomarker-monitoring trials analogous to that in use for the investigation of new drugs. In phase I, biomarker kinetics and correlation with tumor burden are assessed. Phase II evaluates the ability of the biomarker to identify, exclude, and/or predict a change in disease status. In phase III, the effectiveness of tumor biomarker-guided intervention is assessed by measuring patient outcome in randomized trials. Phase IV consists of an audit of the long-term effects after biomarker monitoring has been included into standard patient care. Systematic well-designed evaluations of biomarkers for monitoring may provide a stronger evidence base that might enable their earlier use in evaluating responses to cancer therapy.

Sampling and storage conditions influencing the measurement of parathyroid hormone in blood samples: a systematic review.

Parathyroid hormone (PTH) is relatively unstable: optimisation of pre-analytical conditions, including specimen type, sampling time and storage conditions, is essential. We have undertaken a systematic review of these pre-analytical conditions. An electronic search of the PubMed, Embase, Cochrane, Centre for Research and Dissemination and Bandolier databases was undertaken. Of 5511 papers identified, 96 underwent full text review, of which 83 were finally included. At room temperature PTH was stable in ethylenediaminetetraacetic acid (EDTA) preserved whole blood for at least 24 h and in EDTA plasma for at least 48 h after venepuncture. Losses were observed in clotted blood samples after 3 h and in serum after 2 h. At 4°C PTH was more stable in EDTA plasma (at least 72 h) than serum (at least 24 h). Central venous PTH concentrations were higher than peripheral venous concentrations. In the northern hemisphere, PTH concentrations were higher in winter than summer. PTH has a circadian rhythm characterised by a nocturnal acrophase and mid-morning nadir. Data related to frozen storage of PTH (-20°C and -80°C) were limited and contradictory. We recommend that blood samples for PTH measurement should be taken into tubes containing EDTA, ideally between 10:00 and 16:00, and plasma separated within 24 h of venepuncture. Plasma samples should be stored at 4°C and analysed within 72 h of venepuncture. Particular regard must be paid to the venepuncture site when interpreting PTH concentration. Further research is required to clarify the suitability of freezing samples prior to PTH measurement.

Roadmap for harmonization of clinical laboratory measurement procedures.

Results between different clinical laboratory measurement procedures (CLMP) should be equivalent, within clinically meaningful limits, to enable optimal use of clinical guidelines for disease diagnosis and patient management. When laboratory test results are neither standardized nor harmonized, a different numeric result may be obtained for the same clinical sample. Unfortunately, some guidelines are based on test results from a specific laboratory measurement procedure without consideration of the possibility or likelihood of differences between various procedures. When this happens, aggregation of data from different clinical research investigations and development of appropriate clinical practice guidelines will be flawed. A lack of recognition that results are neither standardized nor harmonized may lead to erroneous clinical, financial, regulatory, or technical decisions. Standardization of CLMPs has been accomplished for several measurands for which primary (pure substance) reference materials exist and/or reference measurement procedures (RMPs) have been developed. However, the harmonization of clinical laboratory procedures for measurands that do not have RMPs has been problematic owing to inadequate definition of the measurand, inadequate analytical specificity for the measurand, inadequate attention to the commutability of reference materials, and lack of a systematic approach for harmonization. To address these problems, an infrastructure must be developed to enable a systematic approach for identification and prioritization of measurands to be harmonized on the basis of clinical importance and technical feasibility, and for management of the technical implementation of a harmonization process for a specific measurand.

Variation in parathyroid hormone immunoassay results--a critical governance issue in the management of chronic kidney disease.

Renal physicians strive to maintain parathyroid hormone (PTH) concentrations for patients with chronic kidney disease (CKD) within guideline limits, but poor method comparability means there is currently serious risk of clinical misclassification. The potential for under- or over-treatment is significant, representing a major challenge to patient safety. In the short-term, raising awareness of clinical implications of method-related differences in PTH is essential. Agreeing and adopting assay-specific PTH action limits for CKD patients as an interim measure is highly desirable and has been achieved in Scotland. Establishing pre-analytical requirements for PTH is also a priority. In the longer term, re-standardization of PTH methods in terms of an appropriate International Standard is required. Provided commutability can be demonstrated, the recently established IS 95/646 for PTH (1-84) is a suitable candidate. Establishment of a well-characterized panel of samples of defined clinical provenance to enable manufacturers to determine appropriate reference intervals and clinical decision points is also recommended and will provide an invaluable clinical resource. Recent developments in mass spectrometry mean that a candidate reference measurement procedure for PTH is now achievable and will represent major progress. Concurrently, evidence-based recommendations on clinical requirements and performance goals for PTH are required. Improving the comparability of PTH results requires support from many stakeholders but is achievable.

Interaction of gonadal status with systemic inflammation and opioid use in determining nutritional status and prognosis in advanced pancreatic cancer.

PURPOSE: Hypogonadism has been linked with systemic inflammation and opioid use in males with advanced cancer. We aimed to investigate the interaction of gonadal status with systemic inflammation and opioids in determining nutritional status and prognosis in advanced pancreatic cancer. METHODS: One hundred and seventy-five patients (92 males, 83 postmenopausal females) with unresectable pancreatic cancer were studied. Serum sex steroids (total testosterone [TT], calculated free testosterone [cFT], oestradiol, sex hormone binding globulin), gonadotropins (follicle-stimulating hormone and luteinising hormone) and pro-inflammatory mediators (C-reactive protein [CRP], interleukin-6 [IL-6], soluble tumour necrosis factor receptor 75 [sTNFR75]) were measured, and nutritional assessment and opioid use recorded. RESULTS: Seventy-three percent of males were hypogonadal (by cFT definition). cFT correlated positively with BMI (r (2) =0.349; p< 0.001) and grip strength (r (2) = 0.229; p = 0.034) and inversely with weight loss (r (2) = -0.287; p = 0.007), CRP (r (2) = -0.426; p < 0.001) and IL-6 (r (2) = -0.303; p = 0.004). CRP (p= 0.007), opioid dosage (p = 0.009) and BMI (p = 0.005) were independent determinants of cFT on ANOVA. Hypogonadal males demonstrated worsened survival compared with eugonadal patients (TT: OR of death = 2.87; p < 0.001; cFT: OR = 2.26; p = 0.011). Furthermore, male opioid use was associated with decreased TT (p < 0.001) and cFT (p < 0.001) and worsened survival (OR = 1.96; p = 0.012). In contrast, 18% of postmenopausal females exhibited premenopausal ("hyperoestrogenic") oestradiol levels. Oestradiol correlated positively with sTNFR75 (r (2) = 0.299; p = 0.008). CRP (p < 0.001) was an independent determinant of oestradiol. Hyperoestrogenic females demonstrated worsened survival compared with eugonadal patients (OR = 2.43; p = 0.013). CONCLUSIONS: In males with pancreatic cancer, systemic inflammation and opioid use are associated with hypogonadism. Male hypogonadism and female hyperoestrogenism are associated with shortened survival in advanced pancreatic cancer.

Perspectives in Clinical Proteomics Conference: translating clinical proteomics into clinical practice.

Although there have been numerous publications on biomarkers, few new tests have been adopted in routine clinical practice. The major purpose of the very interesting multidisciplinary Perspectives in Clinical Proteomics Conference, which was convened under the auspices of the Wellcome Trust at the Wellcome Trust Genome Campus near Cambridge, was to explore reasons for this. Established and emerging proteomic markers in conditions ranging from kidney disease to neurochemical dementia were reviewed on the first day, while presentations on the second day specifically addressed the all-important question, "What does it take to translate a biomarker into clinical use?" More than 70 participants representing 60 organizations, nine countries and varied backgrounds convened in the tranquil surroundings of the Wellcome Trust Genome Campus for this truly multidisciplinary conference. Attendees included representatives from regulatory bodies, research institutions, academic institutions, professional organizations and the diagnostics and pharmaceutical industries. The stated intention of the organizers - Rolf Apweiler, Roz Banks, Mike Dunn, Scott Patterson and Jennifer van Eyk - was to stimulate informed debate and they succeeded admirably. Some highlights from each of the three excellent conference sessions are described briefly here.

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for use of tumor markers in liver, bladder, cervical, and gastric cancers.

BACKGROUND: Updated National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for the use of tumor markers in the clinic have been developed. METHODS: Published reports relevant to use of tumor markers for 4 cancer sites--liver, bladder, cervical, and gastric--were critically reviewed. RESULTS: Alpha-fetoprotein (AFP) may be used in conjunction with abdominal ultrasound for early detection of hepatocellular carcinoma (HCC) in patients with chronic hepatitis or cirrhosis associated with hepatitis B or C virus infection. AFP concentrations >200 microg/L in cirrhotic patients with typical hypervascular lesions >2 cm in size are consistent with HCC. After a diagnosis of HCC, posttreatment monitoring with AFP is recommended as an adjunct to imaging, especially in the absence of measurable disease. Although several urine markers have been proposed for bladder cancer, none at present can replace routine cystoscopy and cytology in the management of patients with this malignancy. Some may, however, be used as complementary adjuncts to direct more effective use of clinical procedures. Although carcinoembryonic antigen and CA 19-9 have been proposed for use gastric cancer and squamous cell carcinoma antigen for use in cervical cancer, none of these markers can currently be recommended for routine clinical use. CONCLUSIONS: Implementation of these recommendations should encourage optimal use of tumor markers for patients with liver, bladder, cervical, or gastric cancers.

Differences in recognition of the 1st WHO international reference reagents for hCG-related isoforms by diagnostic immunoassays for human chorionic gonadotropin.

BACKGROUND: The 1st WHO International Reference Reagents (IRRs) for 6 human chorionic gonadotropin (hCG)-related molecular variants, highly purified and calibrated in substance concentrations by the IFCC Working Group for hCG, permit experimental elucidation of what commercially available hCG methods measure in molar terms and enable assessment of their fitness for clinical purposes. METHODS: Pools containing known amounts of the IRRs spiked into normal human serum were issued to participants through the UK National External Quality Assessment Service for hCG for a period of 7 years. Among 16 assays used, 4 recognized only hCG, whereas 6 recognized hCG and its free beta-subunit (hCGbeta), and 6 recognized hCG, hCGbeta, and the beta core fragment. RESULTS: Differences in calibration of current hCG assays are moderate. Mean recovery of the current International Standard (IS), hCG IS 75/589, was 107% (range 93% to 126%), whereas that of the IRR 99/688 for hCG was 139% (range 109%-164%). Between-method variation for the latter (CV 12.3%) was also greater than for IS 75/589 (CV 8.8%). Recognition of hCGbeta varied markedly (CV 37%). Most assays overestimated it, but 2 RIAs produced results that were slight underestimations. Recognition of the beta core fragment was even more variable (CV 57%) and was closest to equimolarity for the RIAs. CONCLUSIONS: Assays for hCG show considerable variation in their recognition of various forms of hCG, and this variability is the most important cause of method-related differences in hCG results in serum and an even more important cause of method-related differences in urine measurements. Equimolar recognition of the major hCG isoforms is essential if between-method comparability for hCG is to be improved.

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for use of tumor markers in clinical practice: quality requirements.

BACKGROUND: This report presents updated National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines summarizing quality requirements for the use of tumor markers. METHODS: One subcommittee developed guidelines for analytical quality relevant to serum and tissue-based tumor markers in current clinical practice. Two other subcommittees formulated recommendations particularly relevant to the developing technologies of microarrays and mass spectrometry. RESULTS: Prerequisites for optimal use of tumor markers in routine practice include formulation of the correct clinical questions to ensure selection of the appropriate test, adherence to good clinical and laboratory practices (e.g., minimization of the risk of incorrect patient and/or specimen identification, tube type, or timing), use of internationally standardized and well-characterized methods, careful adherence to manufacturer instructions, and proactive and timely reactions to information derived from both internal QC and proficiency-testing specimens. Highly desirable procedures include those designed to minimize the risk of the reporting of erroneous results attributable to interferences such as heterophilic antibodies or hook effects, to facilitate the provision of informative clinical reports (e.g., cumulative and/or graphical reports, appropriately derived reference intervals, and interpretative comments), and when possible to integrate these reports with other patient information through electronic health records. Also mandatory is extensive validation encompassing all stages of analysis before introduction of new technologies such as microarrays and mass spectrometry. Provision of high-quality tumor marker services is facilitated by dialogue involving researchers, diagnostic companies, clinical and laboratory users, and regulatory agencies. CONCLUSIONS: Implementation of these recommendations, adapted to local practice, should encourage optimization of the clinical use of tumor markers.

National Academy of Clinical Biochemistry laboratory medicine practice guidelines for use of tumor markers in testicular, prostate, colorectal, breast, and ovarian cancers.

BACKGROUND: Updated National Academy of Clinical Biochemistry (NACB) Laboratory Medicine Practice Guidelines for the use of tumor markers in the clinic have been developed. METHODS: Published reports relevant to use of tumor markers for 5 cancer sites--testicular, prostate, colorectal, breast, and ovarian--were critically reviewed. RESULTS: For testicular cancer, alpha-fetoprotein, human chorionic gonadotropin, and lactate dehydrogenase are recommended for diagnosis/case finding, staging, prognosis determination, recurrence detection, and therapy monitoring. alpha-Fetoprotein is also recommended for differential diagnosis of nonseminomatous and seminomatous germ cell tumors. Prostate-specific antigen (PSA) is not recommended for prostate cancer screening, but may be used for detecting disease recurrence and monitoring therapy. Free PSA measurement data are useful for distinguishing malignant from benign prostatic disease when total PSA is <10 microg/L. In colorectal cancer, carcinoembryonic antigen is recommended (with some caveats) for prognosis determination, postoperative surveillance, and therapy monitoring in advanced disease. Fecal occult blood testing may be used for screening asymptomatic adults 50 years or older. For breast cancer, estrogen and progesterone receptors are mandatory for predicting response to hormone therapy, human epidermal growth factor receptor-2 measurement is mandatory for predicting response to trastuzumab, and urokinase plasminogen activator/plasminogen activator inhibitor 1 may be used for determining prognosis in lymph node-negative patients. CA15-3/BR27-29 or carcinoembryonic antigen may be used for therapy monitoring in advanced disease. CA125 is recommended (with transvaginal ultrasound) for early detection of ovarian cancer in women at high risk for this disease. CA125 is also recommended for differential diagnosis of suspicious pelvic masses in postmenopausal women, as well as for detection of recurrence, monitoring of therapy, and determination of prognosis in women with ovarian cancer. CONCLUSIONS: Implementation of these recommendations should encourage optimal use of tumor markers.

Improving the comparability of immunoassays for prostate-specific antigen (PSA): progress and problems.

BACKGROUND: Commutability of immunoassay test results is an important objective for laboratory medicine. METHODS: PSA is a clinically important analyte for which, as a consequence of a number of national and international initiatives over the last decade, considerable progress has been made towards improving method comparability. However, results from different assays are still not interchangeable, a situation that is only likely to improve once broad recommendations can be made about the most clinically relevant antibody combinations. CONCLUSIONS: Universal implementation of such recommendations would almost certainly improve between-method agreement substantially, provided careful attention were paid to assay design and use of appropriately pure secondary standards ensured.

Perspective and priorities for improvement of parathyroid hormone (PTH) measurement - A view from the IFCC Working Group for PTH.

Parathyroid hormone (PTH) measurement in serum or plasma is a necessary tool for the exploration of calcium/phosphate disorders, and is widely used as a surrogate marker to assess skeletal and mineral disorders associated with chronic kidney disease (CKD), referred to as CKD-bone mineral disorders (CKD-MBD). CKD currently affects >10% of the adult population in the United States and represents a major health issue worldwide. Disturbances in mineral metabolism and fractures in CKD patients are associated with increased morbidity and mortality. Appropriate identification and management of CKD-MBD is therefore critical to improving clinical outcome. Recent increases in understanding of the complex pathophysiology of CKD, which involves calcium, phosphate and magnesium balance, and is also influenced by vitamin D status and fibroblast growth factor (FGF)-23 production, should facilitate such improvement. Development of evidence-based recommendations about how best to use PTH is limited by considerable method-related variation in results, of up to 5-fold, as well as by lack of clarity about which PTH metabolites these methods recognise. This makes it difficult to compare PTH results from different studies and to develop common reference intervals and/or decision levels for treatment. The implications of these method-related differences for current clinical practice are reviewed here. Work being undertaken by the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) to improve the comparability of PTH measurements worldwide is also described.

Standardization of tumor markers - priorities identified through external quality assessment.

Tumor markers are often heterogeneous substances that may be present in elevated concentrations in the serum of cancer patients. Typically measured by immunoassay, they contribute to clinical management, particularly in screening, case-finding, prognostic assessment, and post-treatment monitoring. Data both from external quality assessment (EQA) schemes and clinical studies demonstrate significant variation in tumor marker results obtained for the same specimen using different methods. Between-method between-laboratory coefficients of variation (CV) reported by EQA schemes generally reflect the complexity of the measurand, ranging from <5% for the structurally relatively simple α-fetoprotein (AFP) to >25% for the complex mucinous cancer antigen 19-9 (CA19-9). Improving the standardization of tumor marker measurements is particularly important for three reasons. The primary use of tumor markers is in monitoring cancer patients over long periods of time. Clinical interpretation of trends may consequently be affected if results are obtained in different laboratories using different methods or if a laboratory has to change method. Differences in results may have major implications for adoption of area-wide decision cut-offs and make implementation of these difficult. Method-related differences also make it difficult to compare clinical studies. Improving comparability of tumor marker results requires broad international agreement about which molecular forms of the measurand have clinical utility, identifying and adopting pure molecular forms as calibrants, and defining antibody specificities for their optimal detection. These aims have been achieved to varying extents for the most frequently measured serum tumor markers as described in this paper.

Alpha-Fetoprotein Detection of Hepatocellular Carcinoma Leads to a Standardized Analysis of Dynamic AFP to Improve Screening Based Detection.

Detection of hepatocellular carcinoma (HCC) through screening can improve outcomes. However, HCC surveillance remains costly, cumbersome and suboptimal. We tested whether and how serum Alpha-Fetoprotein (AFP) should be used in HCC surveillance. Record linkage, dedicated pathways for management and AFP data-storage identified i) consecutive highly characterised cases of HCC diagnosed in 2009-14 and ii) a cohort of ongoing HCC-free patients undergoing regular HCC surveillance from 2009. These two well-defined Scottish patient cohorts enabled us to test the utility of AFP surveillance. Of 304 cases of HCC diagnosed over 6 years, 42% (129) were identified by a dedicated HCC surveillance programme. Of these 129, 47% (61) had a detectable lesion first identified by screening ultrasound (US) but 38% (49) were prompted by elevated AFP. Despite pre-HCC diagnosis AFP >20kU/L being associated with poor outcome, 'AFP-detected' tumours were offered potentially curative management as frequently as 'US-detected' HCCs; and had comparable survival. Linearity of serial log10-transformed AFPs in HCC cases and in the screening 'HCC-free' cohort (n = 1509) provided indicators of high-risk AFP behaviour in HCC cases. An algorithm was devised in static mode, then tested dynamically. A case/control series in hepatitis C related disease demonstrated highly significant detection (p<1.72*10-5) of patients at high risk of developing HCC. These data support the use of AFP in HCC surveillance. We show proof-of-principle that an automated and further refine-able algorithmic interpretation of AFP can identify patients at higher risk of HCC. This approach could provide a cost-effective, user-friendly and much needed addition to US surveillance.

Pregnancy testing with hCG--future prospects.

Pregnancy tests for human chorionic gonadotrophin (hCG) are used widely in hospital and home settings. Assays measuring hCG also have uses in prenatal screening and oncology. The output from three recent international workshops provides a framework for reliable measurement of hCG. Requirements for future hCG assays include use of clear descriptive nomenclature, informed selection of antibodies of well-defined epitope specificities, and design of robust methods. Tests will be precisely characterized and calibrated in SI units using six International Reference Reagents (IRR) for hCG and variants, and the Fifth International Standard for hCG 07/364, making it possible to report clinical results in molar units. These measures will help to increase patient safety by reducing the risk of erroneous or misleading hCG results.