High-risk symptoms and quantitative faecal immunochemical test accuracy: Systematic review and meta-analysis.

BACKGROUND: The quantitative faecal immunochemical test for haemoglobin (FIT) has been revealed to be highly accurate for colorectal cancer (CRC) detection not only in a screening setting, but also in the assessment of patients presenting lower bowel symptoms. Therefore, the National Institute for Health and Care Excellence has recommended the adoption of FIT in primary care to guide referral for suspected CRC in low-risk symptomatic patients using a 10 µg Hb/g faeces threshold. Nevertheless, it is unknown whether FIT´s accuracy remains stable throughout the broad spectrum of possible symptoms. AIM: To perform a systematic review and meta-analysis to assess FIT accuracy for CRC detection in different clinical settings. METHODS: A systematic literature search was performed using MEDLINE and EMBASE databases from inception to May 2018 to conduct a meta-analysis of prospective studies including symptomatic patients that evaluated the diagnostic accuracy of quantitative FIT for CRC detection. Studies were classified on the basis of brand, threshold of faecal haemoglobin concentration for a positive test result, percentage of reported symptoms (solely symptomatic, mixed cohorts) and CRC prevalence (< 2.5%, ≥ 2.5%) to limit heterogeneity and perform subgroup analysis to assess the influence of clinical spectrum on FIT´s accuracy to detect CRC. RESULTS: Fifteen cohorts including 13073 patients (CRC prevalence 0.4% to 16.8%) were identified. Pooled estimates of sensitivity for studies using OC-Sensor at 10 µg Hb/g faeces threshold (n = 10400) was 89.6% [95% confidence interval (CI): 82.7% to 94.0%). However, pooled estimates of sensitivity for studies formed solely by symptomatic patients (n = 4035) and mixed cohorts (n = 6365) were 94.1% (95%CI: 90.0% to 96.6%) and 85.5% (95%CI: 76.5% to 91.4%) respectively (P < 0.01), while there were no statistically significant differences between pooled sensitivity of studies with CRC prevalence < 2.5% (84.9%, 95%CI: 73.4% to 92.0%) and ≥ 2.5% (91.7%, 95%CI: 83.3% to 96.1%) (P = 0.25). At the same threshold, OC-Sensor® sensitivity to rule out any significant colonic lesion was 78.6% (95%CI: 75.6% to 81.4%). We found substantial heterogeneity especially when assessing specificity. CONCLUSION: The results of this meta-analysis confirm that, regardless of CRC prevalence, quantitative FIT is highly sensitive for CRC detection. However, FIT ability to rule out CRC is higher in studies solely including symptomatic patients.

Detection capability of quantitative faecal immunochemical tests for haemoglobin (FIT) and reporting of low faecal haemoglobin concentrations.

Faecal immunochemical tests for haemoglobin (FIT) are widely used in asymptomatic population screening for colorectal (bowel) cancer. FIT are also used to assist with the assessment of patients presenting with lower abdominal symptoms. Quantitative FIT allow the generation of numerical estimates of faecal haemoglobin (f-Hb) concentrations. There is now great interest in "low" f-Hb concentrations in these clinical settings: in consequence, knowledge of the detection capability is very important for f-Hb concentration examinations. There are a number of current problems associated with the reporting of low f-Hb concentrations and wide misunderstanding of the metrological aspects of examinations of f-Hb at low concentrations. These would be solved if the detectability characteristics of f-Hb concentration examinations, namely, the limit of blank (LoB), limit of detection (LoD) and limit of quantitation (LoQ), were generated, validated and used in reporting systems exactly as recommended in the EP17-A2 guideline of the Clinical Laboratory Standards Institute. LoB and LoD are statistical concepts, but the LoQ depends on definition of analytical performance specifications (APS). In this Opinion Paper proposals for interim APS are made, based on the current state of the art achieved with examinations of faecal samples. It is proposed that LoQ is determined at an examination imprecision of CV≤10% using faecal samples naturally positive for Hb rather than faeces spiked with haemolysate. Detailed proposals for reporting f-Hb data at low concentrations are also made.

Role of cytology and immunochemistry in diagnosis of metastatic malignancies in the lung: A critical appraisal.

BACKGROUND: Lung is one of the most common sites for primary and metastatic malignancies and a challenging site to diagnose primary versus a metastatic origin of the tumor on cytology. Pathologic diagnosis of the site of origin of cancer has major implications in the management and staging purposes and may have to be followed by testing for predictive/prognostic markers. The clinical history of a known extrapulmonary primary and the radiologic findings of multiple nodules in the lung are useful in arriving at the right diagnosis but is not always available. Rarely pulmonary metastasis may be the first manifestation of an extrapulmonary tumor or may even present as a single nodule. METHOD: In this study, we reviewed cytomorphologic features of tumors metastatic to the lung (2014-2017) in conjunction with immunochemistry and evaluation of needle core biopsy when available. The review of the slides was performed with an emphasis on our ability to identify the site of origin in the tumors. RESULTS: We identified 47 cases of metastatic tumors in the lung diagnosed on cytology. Clinical history was available in 83% cases and with aid of immunostains, a definitive diagnosis on the origin of the tumor was made in all these cases. In the remaining 8 cases, a primary origin could only be suggested. The use of immunochemistry facilitated the diagnosis but could be misleading. CONCLUSION: The approach to the diagnosis of metastatic tumors in the lung on cytology should be largely guided by the previous clinical history and comparison with previous tissue/cellular material if available.

NCCN Guidelines Insights: Colorectal Cancer Screening, Version 1.2018.

The NCCN Guidelines for Colorectal Cancer (CRC) Screening outline various screening modalities as well as recommended screening strategies for individuals at average or increased-risk of developing sporadic CRC. The NCCN panel meets at least annually to review comments from reviewers within their institutions, examine relevant data, and reevaluate and update their recommendations. These NCCN Guidelines Insights summarize 2018 updates to the NCCN Guidelines, with a primary focus on modalities used to screen individuals at average-risk for CRC.

Quality Control Practices for Chemistry and Immunochemistry in a Cohort of 21 Large Academic Medical Centers.

OBJECTIVES: In the United States, minimum standards for quality control (QC) are specified in federal law under the Clinical Laboratory Improvement Amendment and its revisions. Beyond meeting this required standard, laboratories have flexibility to determine their overall QC program. METHODS: We surveyed chemistry and immunochemistry QC procedures at 21 clinical laboratories within leading academic medical centers to assess if standardized QC practices exist for chemistry and immunochemistry testing. RESULTS: We observed significant variation and unexpected similarities in practice across laboratories, including QC frequency, cutoffs, number of levels analyzed, and other features. CONCLUSIONS: This variation in practice indicates an opportunity exists to establish an evidence-based approach to QC that can be generalized across institutions.

Novel artificial stool material for external quality assurance (EQA) on a fecal immunochemical test for hemoglobin (FIT): The confirmed utility of stable hemoglobin and an internal standard material.

The fecal immunochemical test for hemoglobin (FIT), which detects lower gastrointestinal bleeding, is widely accepted for population-based colorectal cancer (CRC) screening programs. However, the FIT screening process has not been standardized yet, and standardizing the pre-analytical phase and establishing an external quality assurance (EQA) program compliant with ISO requirements is urgently needed. Although there have been various attempts to establish EQA materials suitable for FIT, no materials have yet been reported to have sufficient uniformity and acceptable immunochemical stability of hemoglobin (Hb). The Health Care Technology Foundation (HECTEF; Tokyo Japan) is now developing a ready-to-use artificial stool containing Hb and an internal standard, glycerol. Accordingly, we verified the adaptability and efficacy of this material for the evaluation of the specimen collection phase of FIT. This material uniformly contained both Hb and glycerol. The glycerol allowed us to estimate the weight of the collected artificial stool and to correct the Hb concentration with the estimated weight. Furthermore, the stability of both Hb and glycerol were confirmed to be sufficient for an EQA material under appropriate storage, in-use, repeated freeze-thaw, and heated conditions. These in-house performance characteristics suggest that HECTEF artificial stool is acceptable as an EQA material for FIT.

Microbiota-based model improves the sensitivity of fecal immunochemical test for detecting colonic lesions.

BACKGROUND: Colorectal cancer (CRC) is the second leading cause of death among cancers in the United States. Although individuals diagnosed early have a greater than 90% chance of survival, more than one-third of individuals do not adhere to screening recommendations partly because the standard diagnostics, colonoscopy and sigmoidoscopy, are expensive and invasive. Thus, there is a great need to improve the sensitivity of non-invasive tests to detect early stage cancers and adenomas. Numerous studies have identified shifts in the composition of the gut microbiota associated with the progression of CRC, suggesting that the gut microbiota may represent a reservoir of biomarkers that would complement existing non-invasive methods such as the widely used fecal immunochemical test (FIT). METHODS: We sequenced the 16S rRNA genes from the stool samples of 490 patients. We used the relative abundances of the bacterial populations within each sample to develop a random forest classification model that detects colonic lesions using the relative abundance of gut microbiota and the concentration of hemoglobin in stool. RESULTS: The microbiota-based random forest model detected 91.7% of cancers and 45.5% of adenomas while FIT alone detected 75.0% and 15.7%, respectively. Of the colonic lesions missed by FIT, the model detected 70.0% of cancers and 37.7% of adenomas. We confirmed known associations of Porphyromonas assaccharolytica, Peptostreptococcus stomatis, Parvimonas micra, and Fusobacterium nucleatum with CRC. Yet, we found that the loss of potentially beneficial organisms, such as members of the Lachnospiraceae, was more predictive for identifying patients with adenomas when used in combination with FIT. CONCLUSIONS: These findings demonstrate the potential for microbiota analysis to complement existing screening methods to improve detection of colonic lesions.

[Role of Medical Technologists as Certified Clinical Chemistry and Inununochemistry Test Quality Assurance Managers in International Standardization].

In Japan, biochemical testing has been standardized by establishing secondary reference measurement procedures for each method under the leadership of the Japan Society of Clinical Chemistry (JSCC). This has led to the assignment of values to secondary calibration materials, enabling laboratories to manage the accuracy of measurement values using them. To promote the sharing of test data by standardizing base facilities on a nationwide basis, the Japanese As- sociation of Medical Technologists (JAMT) launched the Laboratory Test Data Standardization Project. The range of reference for biochemical testing was calculated, and the absence of regional differences in such a range was confirmed by standardized base facilities throughout Japan. Through collaboration between the JSCC and JAMT, the Clinical Chemistry and Immunochemistry Test Quality Assurance Manager Certification System was established in 2014, with a view to promoting quality assurance in laboratories. It is expected that medical technologists who are certified as such managers will contribute to the nationwide provision of high-quality medical services. [Review].

Importance of implementing an analytical quality control system in a core laboratory.

INTRODUCTION: The aim of the clinical laboratory is to provide useful information for screening, diagnosis and monitoring of disease. The laboratory should ensure the quality of extra-analytical and analytical process, based on set criteria. To do this, it develops and implements a system of internal quality control, designed to detect errors, and compare its data with other laboratories, through external quality control. In this way it has a tool to detect the fulfillment of the objectives set, and in case of errors, allowing corrective actions to be made, and ensure the reliability of the results. OBJECTIVE: This article sets out to describe the design and implementation of an internal quality control protocol, as well as its periodical assessment intervals (6 months) to determine compliance with pre-determined specifications (Stockholm Consensus(1)). MATERIALS AND METHODS: A total of 40 biochemical and 15 immunochemical methods were evaluated using three different control materials. Next, a standard operation procedure was planned to develop a system of internal quality control that included calculating the error of the analytical process, setting quality specifications, and verifying compliance. RESULTS: The quality control data were then statistically depicted as means, standard deviations, and coefficients of variation, as well as systematic, random, and total errors. The quality specifications were then fixed and the operational rules to apply in the analytical process were calculated. Finally, our data were compared with those of other laboratories through an external quality assurance program. DISCUSSION: The development of an analytical quality control system is a highly structured process. This should be designed to detect errors that compromise the stability of the analytical process. The laboratory should review its quality indicators, systematic, random and total error at regular intervals, in order to ensure that they are meeting pre-determined specifications, and if not, apply the appropriate corrective actions.

THE EFFECT OF PHLEBOTOMY-INDUCED HEMOLYSIS ON INSULIN LEVEL DETERMINATION.

OBJECTIVE: To examine the effect of phlebotomy-induced hemolysis on serum insulin and C-peptide measurement by an immunochemiluminometric assay. METHODS: As part of a study designed to evaluate ß-cell function in a group of adults with newly diagnosed type 2 diabetes, we tested insulin and C-peptide levels in 1,048 samples. In order to evaluate the effect of phlebotomy-induced hemolysis, we determined insulin and C-peptide levels simultaneously in hemolyzed and nonhemolyzed samples. RESULTS: Forty-seven (4.5%) of the 1,048 samples were affected by hemolysis. In 26 cases, we had paired hemolyzed and nonhemolyzed serum samples that allowed a simultaneous comparison. We found that all degrees of hemolysis led to a significant decrease in insulin level. In hemolyzed serum, the median (interquartile range) of the insulin was 5.6 (1.8 to 24.3) mIU/L, versus 21.3 (11.4 to 48.5) mIU/L in nonhemolyzed serum, representing a 25 to 98% loss. This phenomenon was not found for C-peptide levels. CONCLUSION: Clinicians have to be aware that even a mild degree of phlebotomy-induced hemolysis has a significant effect on serum insulin level determination, which can lead to misinterpretation of test results. This finding has important implications, especially in the evaluation of suspected cases of hyperinsulinemic hypoglycemia.

Primary afferent and spinal cord expression of gastrin-releasing peptide: message, protein, and antibody concerns.

There is continuing controversy relating to the primary afferent neurotransmitter that conveys itch signals to the spinal cord. Here, we investigated the DRG and spinal cord expression of the putative primary afferent-derived "itch" neurotransmitter, gastrin-releasing peptide (GRP). Using ISH, qPCR, and immunohistochemistry, we conclude that GRP is expressed abundantly in spinal cord, but not in DRG neurons. Titration of the most commonly used GRP antiserum in tissues from wild-type and GRP mutant mice indicates that the antiserum is only selective for GRP at high dilutions. Paralleling these observations, we found that a GRPeGFP transgenic reporter mouse has abundant expression in superficial dorsal horn neurons, but not in the DRG. In contrast to previous studies, neither dorsal rhizotomy nor an intrathecal injection of capsaicin, which completely eliminated spinal cord TRPV1-immunoreactive terminals, altered dorsal horn GRP immunoreactivity. Unexpectedly, however, peripheral nerve injury induced significant GRP expression in a heterogeneous population of DRG neurons. Finally, dual labeling and retrograde tracing studies showed that GRP-expressing neurons of the superficial dorsal horn are predominantly interneurons, that a small number coexpress protein kinase C gamma (PKCγ), but that none coexpress the GRP receptor (GRPR). Our studies support the view that pruritogens engage spinal cord "itch" circuits via excitatory superficial dorsal horn interneurons that express GRP and that likely target GRPR-expressing interneurons. The fact that peripheral nerve injury induced de novo GRP expression in DRG neurons points to a novel contribution of this peptide to pruritoceptive processing in neuropathic itch conditions.

Accuracy of fecal immunochemical tests for colorectal cancer: systematic review and meta-analysis.

BACKGROUND: Performance characteristics of fecal immunochemical tests (FITs) to screen for colorectal cancer (CRC) have been inconsistent. PURPOSE: To synthesize data about the diagnostic accuracy of FITs for CRC and identify factors affecting its performance characteristics. DATA SOURCES: Online databases, including MEDLINE and EMBASE, and bibliographies of included studies from 1996 to 2013. STUDY SELECTION: All studies evaluating the diagnostic accuracy of FITs for CRC in asymptomatic, average-risk adults. DATA EXTRACTION: Two reviewers independently extracted data and critiqued study quality. DATA SYNTHESIS: Nineteen eligible studies were included and meta-analyzed. The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of FITs for CRC were 0.79 (95% CI, 0.69 to 0.86), 0.94 (CI, 0.92 to 0.95), 13.10 (CI, 10.49 to 16.35), 0.23 (CI, 0.15 to 0.33), respectively, with an overall diagnostic accuracy of 95% (CI, 93% to 97%). There was substantial heterogeneity between studies in both the pooled sensitivity and specificity estimates. Stratifying by cutoff value for a positive test result or removal of discontinued FIT brands resulted in homogeneous sensitivity estimates. Sensitivity for CRC improved with lower assay cutoff values for a positive test result (for example, 0.89 [CI, 0.80 to 0.95] at a cutoff value less than 20 µg/g vs. 0.70 [CI, 0.55 to 0.81] at cutoff values of 20 to 50 µg/g) but with a corresponding decrease in specificity. A single-sample FIT had similar sensitivity and specificity as several samples, independent of FIT brand. LIMITATIONS: Only English-language articles were included. Lack of data prevented complete subgroup analyses by FIT brand. CONCLUSION: Fecal immunochemical tests are moderately sensitive, are highly specific, and have high overall diagnostic accuracy for detecting CRC. Diagnostic performance of FITs depends on the cutoff value for a positive test result. PRIMARY FUNDING SOURCE: National Institute of Diabetes and Digestive and Kidney Diseases and National Cancer Institute.

Comparison of copper labeling followed by liquid chromatography-inductively coupled plasma mass spectrometry and immunochemical assays for serum hepcidin-25 determination.

Hepcidin-25 has been defined as the key biomarker in iron metabolism. This peptide binds to the iron transporter ferroportin to cause its degradation. Therefore, the need for specific, accurate and precise methods for the quantification of hepcidin-25 in biological fluids is dramatically increasing. In this regard, the use of rapid immunochemical methods that provide low limit of quantification is desired for routine clinical use. However, such fast methodologies should be first analytically evaluated and compared with alternative strategies to check for their advantages and limitations. Here we compare the use of a commercial immunochemical assay for hepcidin determination with a novel analytical approach based on Cu-labeling of the peptide followed by Cu determination using liquid chromatography (HPLC) and plasma mass spectrometry (ICP-MS). The figures of merit of both systems reveal similar analytical characteristics and both seem to be adequate for the determination of the peptide at biologically relevant concentrations in human serum samples. The analysis of a larger number of samples (n=50) by both techniques showed a good agreement in the concentrations found. Such finding permits to address the hepcidin recovery in the sample preparation procedure necessary for the HPLC-ICP-MS analysis in human serum that turn out to be 76-85%. Additionally, limitations due to cross-reactivity issues of the ELISA method could be addressed in some of the samples by using LC-ICP-MS and were confirmed by LC-Electrospray-MS.

Development of a Protein Standard Absolute Quantification (PSAQ™) assay for the quantification of Staphylococcus aureus enterotoxin A in serum.

Enterotoxin A (SEA) is a staphylococcal virulence factor which is suspected to worsen septic shock prognosis. However, the presence of SEA in the blood of sepsis patients has never been demonstrated. We have developed a mass spectrometry-based assay for the targeted and absolute quantification of SEA in serum. To enhance sensitivity and specificity, we combined an immunoaffinity-based sample preparation with mass spectrometry analysis in the selected reaction monitoring (SRM) mode. Absolute quantification of SEA was performed using the PSAQ™ method (Protein Standard Absolute Quantification), which uses a full-length isotope-labeled SEA as internal standard. The lower limit of detection (LLOD) and lower limit of quantification (LLOQ) were estimated at 352pg/mL and 1057pg/mL, respectively. SEA recovery after immunocapture was determined to be 7.8±1.4%. Therefore, we assumed that less than 1femtomole of each SEA proteotypic peptide was injected on the liquid chromatography column before SRM analysis. From a 6-point titration experiment, quantification accuracy was determined to be 77% and precision at LLOQ was lower than 5%. With this sensitive PSAQ-SRM assay, we expect to contribute to decipher the pathophysiological role of SEA in severe sepsis. This article is part of a Special Issue entitled: Proteomics: The clinical link.

Análisis interlaboratorio de parámetros inmunoquímicos, paraproteínas y bandas oligoclonales. Informe técnico del IV Taller de Inmunoquímica de laSociedad Española de Inmunología / Report of the IV workshop on immunochemistry of the Spanish Society of immunology

Objetivo: El IV Taller de Inmunoquímica, auspiciado por la SociedadEspañola de Inmunología, consistió en la realización de una serie de comparaciones interlaboratorio para evaluar la homogeneidad de los métodos analíticos en Inmunoquímica (IQ). El objetivo de los Talleres de IQ esdesarrollar herramientas de control de calidad y guías de trabajo que permitan estandarizar los distintos procedimientos analíticos, empleados enel diagnóstico clínico. Métodos: En el Taller 2005, en 21 laboratorios se valoraron los parámetros IQ: Inmunoglobulinas IgG, IgA, IgM, total IgE, cadenas ligeras κ y λ,C3, C4, FR, PCR y ASLO en muestras de Controles Comerciales. Tambiénse analizaron las paraproteínas en muestras de suero y orina y por vez primera se incorporó el estudio de bandas oligoclonales en líquido cefalorraquídeo (..) (AU)

Objective: The IV Immunochemistry Workshop supported by the“Sociedad Española de Inmunología” (SEI), consisted in a series of interlaboratory comparative studies to evaluate the homogeneity of the analytic methods in immunochemistry. The objective was to develop qualitycontrol tools to standardise diagnostic analytic procedures. Methods: 21 centres have participated in the Workshop. It comprisedthe quantification of IgG, IgA, IgM, and total IgE κ and λ light chain Immunoglobulin; Complement C3 and C4; Rheumatoid Factor (RF); C-reactiveprotein (CRP), and Antiestreptolysin O (ASL) in commercial control serum samples. Monoclonal immunoglobulins present in serum and urine samples were also characterized. For the first time, the study of LCR oligoclonal bands in the serum and cerebrospinal fluid was incorporated. Thestudy was performed using the routine methods currently used in eachlaboratory. The participant laboratories sent the records of the results to (..) (AU)

A comparison of three stool tests for colorectal cancer screening.

The annual guaiac or immunochemical fecal occult blood test (FOBT) is one of the five colorectal cancer (CRC) screening regimens recommended by the American Cancer Society (Smith, Cokkinides, & Eyre, 2005). Stool-based deoxyribonucleic acid (DNA) testing for CRC is considered a promising technology (Smith, Cokkinides, & Eyre, 2003). Numerous features of three noninvasive stool tests for CRC are compared.

Consensus recommendations of the Italian Association for Neuroimmunology for immunochemical cerebrospinal fluid examination.

In 2002-2003, the Italian Association for Neuroimmunology (AINI) ran a program for procedure and method standardization in neuroimmunology. The main purposes of the program were: a) to improve the overall quality of analytical performance and, simultaneously, to reduce costs by resource optimization; b) to establish the bases for clinical guidelines in neurology; c) to promote the formation of laboratory networks and of joint research projects; d) to facilitate the procedures for certification required by governmental/non-governmental agencies. This report summarizes the consensus recommendations of a panel of AINI neuroimmunologists/biochemists involved in the field of cerebrospinal fluid examination. The collection process for said recommendations was guided by "impact-factored" literature and the knowledge of the experts involved. Communication was by email and face-to-face at two dedicated AINI workshops.