Rejection of Fecal Immunochemical Tests Within the Lower Gastrointestinal Diagnostic Pathway: A Cohort Study.

INTRODUCTION/OBJECTIVES: The fecal immunochemical test (FIT) helps triage primary care patients at risk of colorectal cancer (CRC). Improving FIT returns has received recent attention, however uncertainty exists regarding the accurate completion of samples provided for laboratory analysis. This study aims to identify the rejection rate of returned FIT samples and determine rejection causes. METHODS: FIT samples from symptomatic patients within South Yorkshire, Bassetlaw, and North Derbyshire are processed at a central laboratory. Tests requests are made from 225 GP practices, which serve an estimated 2 million population. This study describes a retrospective review of FIT samples received in the central laboratory between 01/09/19 and 31/12/22. Locally held data was interrogated in March 2023 to determine the number of FIT samples received and rejected during the study period. Documented reasons for rejection were explored to identify common themes. RESULTS: Total FIT specimens received during the study period was 126 422. Of these, 5190 (4.1%) were rejected. Monthly rejection rates fell from 17.4% in September 2019 to 1.3% in December 2022 (P < .001). Sampling errors were the most frequent cause for FIT rejection (2151/5190), with other causes including: expired specimen; no sample collection date/ time, no request form, incomplete patient information and illegible handwriting. CONCLUSIONS: This is the first study exploring FIT rejection rates in symptomatic primary care patients, which shows improvements in rejection rates over time. Targeted interventions could improve rejection rates further, thereby reducing NHS resource use and costs and diagnostic delays.

Fecal Immunochemical Testing in Patients With Low-Risk Symptoms of Colorectal Cancer: A Diagnostic Accuracy Study.

BACKGROUND: The fecal immunochemical test (FIT) is recommended for triaging primary care patients in England with low-risk symptoms of colorectal cancer (CRC). The evidence underpinning recommendations by the National Institute for Health and Care Excellence had limitations, with a paucity of primary care evidence. This study examines the diagnostic accuracy of FIT in a defined low-risk symptom primary care population. PATIENTS AND METHODS: Consecutive symptomatic adult patients referred for a FIT between October and December 2019 were included. Patients were derived from 225 primary care practices in England. Serious colorectal diseases (CRC, high-risk polyps, and inflammatory bowel disease [IBD]) were identified through patient follow-up over 18 months, using both primary and secondary healthcare records. Performance characteristics of FIT are reported according to differing thresholds, including the currently recommended threshold of ≥10 µg hemoglobin per gram of feces (µg/g). RESULTS: A total of 3,506 patients were included in the final analysis. Of these, 708 had a positive FIT result (≥10 µg/g). The prevalence of CRC was 1.3%. FIT positivity declined from 20.2% to 5.8% and 4.5% at cutoffs of 10, 80, and 120 µg/g, respectively. The sensitivity of FIT at ≥10 µg/g to detect CRC was 91.1% (95% CI, 77.9%-97.1%); its specificity was 80.7% (95% CI, 79.3%-82.0%); the positive predictive value (PPV) was 5.8% (95% CI, 4.2%-7.8%); and the negative predictive value (NPV) was 99.9% (95% CI, 99.6%-99.95%). The area under the receiver operating characteristic curve was 0.93 (0.91-0.96). PPV and specificity increased, whereas sensitivity and NPV decreased when serious colorectal diseases (CRC, high-risk polyps, and IBD) were combined. Age, sex, socioeconomic deprivation, and anemia did not significantly influence FIT sensitivity on subgroup analysis. CONCLUSIONS: Utilization of FIT at a threshold ≥10 µg/g can safely triage patients with low-risk symptoms in primary care, with negative results effectively ruling out CRC.

Whole-genome sequencing of a sporadic primary immunodeficiency cohort.

Primary immunodeficiency (PID) is characterized by recurrent and often life-threatening infections, autoimmunity and cancer, and it poses major diagnostic and therapeutic challenges. Although the most severe forms of PID are identified in early childhood, most patients present in adulthood, typically with no apparent family history and a variable clinical phenotype of widespread immune dysregulation: about 25% of patients have autoimmune disease, allergy is prevalent and up to 10% develop lymphoid malignancies1-3. Consequently, in sporadic (or non-familial) PID genetic diagnosis is difficult and the role of genetics is not well defined. Here we address these challenges by performing whole-genome sequencing in a large PID cohort of 1,318 participants. An analysis of the coding regions of the genome in 886 index cases of PID found that disease-causing mutations in known genes that are implicated in monogenic PID occurred in 10.3% of these patients, and a Bayesian approach (BeviMed4) identified multiple new candidate PID-associated genes, including IVNS1ABP. We also examined the noncoding genome, and found deletions in regulatory regions that contribute to disease causation. In addition, we used a genome-wide association study to identify loci that are associated with PID, and found evidence for the colocalization of-and interplay between-novel high-penetrance monogenic variants and common variants (at the PTPN2 and SOCS1 loci). This begins to explain the contribution of common variants to the variable penetrance and phenotypic complexity that are observed in PID. Thus, using a cohort-based whole-genome-sequencing approach in the diagnosis of PID can increase diagnostic yield and further our understanding of the key pathways that influence immune responsiveness in humans.

British Lung Foundation/United Kingdom Primary Immunodeficiency Network Consensus Statement on the Definition, Diagnosis, and Management of Granulomatous-Lymphocytic Interstitial Lung Disease in Common Variable Immunodeficiency Disorders.

A proportion of people living with common variable immunodeficiency disorders develop granulomatous-lymphocytic interstitial lung disease (GLILD). We aimed to develop a consensus statement on the definition, diagnosis, and management of GLILD. All UK specialist centers were contacted and relevant physicians were invited to take part in a 3-round online Delphi process. Responses were graded as Strongly Agree, Tend to Agree, Neither Agree nor Disagree, Tend to Disagree, and Strongly Disagree, scored +1, +0.5, 0, -0.5, and -1, respectively. Agreement was defined as greater than or equal to 80% consensus. Scores are reported as mean ± SD. There was 100% agreement (score, 0.92 ± 0.19) for the following definition: "GLILD is a distinct clinico-radio-pathological ILD occurring in patients with [common variable immunodeficiency disorders], associated with a lymphocytic infiltrate and/or granuloma in the lung, and in whom other conditions have been considered and where possible excluded." There was consensus that the workup of suspected GLILD requires chest computed tomography (CT) (0.98 ± 0.01), lung function tests (eg, gas transfer, 0.94 ± 0.17), bronchoscopy to exclude infection (0.63 ± 0.50), and lung biopsy (0.58 ± 0.40). There was no consensus on whether expectant management following optimization of immunoglobulin therapy was acceptable: 67% agreed, 25% disagreed, score 0.38 ± 0.59; 90% agreed that when treatment was required, first-line treatment should be with corticosteroids alone (score, 0.55 ± 0.51).