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Background: Faecal immunochemical tests (FITs) are used to triage primary care patients with symptoms that could be caused by colorectal cancer for referral to colonoscopy. The aim of this study was to determine whether combining FIT with routine blood test results could improve the performance of FIT in the primary care setting.Methods: Results of all consecutive FITs requested by primary care providers between March 2017 and December 2020 were retrieved from the Oxford University Hospitals NHS Foundation Trust. Demographic factors (age, sex), reason for referral, and results of blood tests within 90 days were also retrieved. Patients were followed up for incident colorectal cancer in linked hospital records. The sensitivity, specificity, positive and negative predictive values of FIT alone, FIT paired with blood test results, and several multivariable FIT models, were compared.Results: One hundred thirty-nine colorectal cancers were diagnosed (0.8%). Sensitivity and specificity of FIT alone at a threshold of 10 μg Hb/g were 92.1 and 91.5% respectively. Compared to FIT alone, blood test results did not improve the performance of FIT. Pairing blood test results with FIT increased specificity but decreased sensitivity. Multivariable models including blood tests performed similarly to FIT alone.Conclusions: FIT is a highly sensitive tool for identifying higher risk individuals presenting to primary care with lower risk symptoms. Combining blood test results with FIT does not appear to lead to better discrimination for colorectal cancer than using FIT alone. [ABSTRACT FROM AUTHOR]

Background: Monitoring is the mainstay of chronic kidney disease management in primary care; however, there is little evidence about the best way to do this.Aim: To compare the effectiveness of estimated glomerular filtration rate (eGFR) derived from serum creatinine and serum cystatin C to predict renal function decline among those with a recent eGFR of 30-89 ml/min/1.73 m2.Design and Setting: Observational cohort study in UK primary care.Method: Serum creatinine and serum cystatin C were both measured at seven study visits over 2 years in 750 patients aged ≥18 years with an eGFR of 30-89 ml/min/1.73 m2 within the previous year. The primary outcome was change in eGFR derived from serum creatinine or serum cystatin C between 6 and 24 months.Results: Average change in eGFR was 0.51 ml/min/1.73 m2/year when estimated by serum creatinine and -2.35 ml/min/1.73 m2/year when estimated by serum cystatin C. The c-statistic for predicting renal decline using serum creatininederived eGFR was 0.495 (95% confidence interval [CI] = 0.471 to 0.519). The equivalent c-statistic using serum cystatin C-derived eGFR was 0.497 (95% CI = 0.468 to 0.525). Similar results were obtained when restricting analyses to those aged ≥75 or <75 years, or with eGFR ≥60 ml/min/1.73 m2. In those with eGFR <60 ml/min/1.73 m2, serum cystatin C-derived eGFR was more predictive than serum creatinine-derived eGFR for future decline in kidney function.Conclusion: In the primary analysis neither eGFR estimated from serum creatinine nor from serum cystatin C predicted future change in kidney function, partly due to small changes during 2 years. In some secondary analyses there was a suggestion that serum cystatin C was a more useful biomarker to estimate eGFR, especially in those with a baseline eGFR <60 ml/min/1.73 m2. [ABSTRACT FROM AUTHOR]

Summary: Background: Faecal immunochemical testing (FIT) is recommended by the National Institute for Health and Care Excellence (NICE) to triage symptomatic primary care patients for further investigation of colorectal cancer. Aim: To ascertain the diagnostic performance of FIT in symptomatic adult primary care patients. Methods: Faecal samples from routine primary care practice in Oxfordshire, UK were analysed using the HM‐JACKarc FIT method between March 2017 and March 2020. Clinical details were recorded. Patients were followed for up to 36 months in linked hospital records for evidence of benign and serious (colorectal cancer, high‐risk adenomas and bowel inflammation) colorectal disease. The diagnostic accuracy of FIT is reported by gender, age group and FIT threshold. Results: In 9896 adult patients with at least 6‐month follow‐up, a FIT result ≥10 µg Hb/g faeces had a sensitivity for colorectal cancer of 90.5% (95% CI 84.9%‐96.1%), specificity 91.3% (90.8%‐91.9%), positive predictive value (PPV) 10.1% (8.15%‐12.0%) and negative predictive value (NPV) 99.9% (99.8%‐100.0%). The PPV and specificity for serious colorectal disease were higher and the sensitivity and NPV lower than for colorectal cancer alone. The area under the curve for all adults did not change substantially by gender or by increasing the minimum age of testing. Using ≥10 µg Hb/g faeces, 10% of adults would be investigated to detect 91% of cancers, a number needed to scope of ten to detect one cancer. Using ≥7, ≥50 and ≥150 µg Hb/g faeces, 11%, 4% and 3% of adults would be investigated, and 91%, 74% and 54% cancers detected, respectively. Conclusion: A FIT threshold of ≥10 µg Hb/g faeces would be appropriate to triage adult patients presenting to primary care with symptoms of serious colorectal disease. FIT may be used to reprioritise patients referred with colorectal cancer symptoms whose investigations have been delayed by the COVID‐19 pandemic. [ABSTRACT FROM AUTHOR]

Background: Creatinine-based estimated glomerular filtration rate (eGFR) determines chronic kidney disease (CKD) stage, but underestimates renal function. The 2014 updated guidance from the National Institute for Health and Care Excellence (NICE) recommends that GPs reduce overdiagnosis of CKD stage 3a (eGFR 45-60 ml/min/1.73 m2) by using the renal biomarker cystatin C.Aim: To determine the population requirement for cystatin C testing, compared with current national availability of the assay.Design and Setting: Retrospective study of primary care laboratory requests in Oxfordshire, England.Method: The first creatinine results from tests ordered in primary care over a 6-year period (2008-2014) in a population of 600 000 in Oxfordshire were analysed and the number of patients with CKD stage 3a without proteinuria (who, in accordance with NICE guidance, required cystatin C) was determined. A conservative estimate of the national need was provided by scaling the population of Oxfordshire to the national population (CKD prevalence in the county is below the national average). Cystatin C assay availability was determined using national databases of laboratory assay provision.Results: From a population of 600 000, there were 22 240 individuals with stable stage 3a CKD and no proteinuria. As the population of Oxfordshire equates to 1% of the UK population, there is an initial requirement for at least 2 million people to have their CKD status determined with cystatin C testing. Eight laboratories (2.1% of UK laboratories) reported cystatin C assay provision.Conclusion: There is a substantial gap between cystatin C assay requirements in primary care and national assay provision. This is a major barrier to implementing NICE guidance. [ABSTRACT FROM AUTHOR]

To understand Cancer Antigen 125 (CA125) testing in primary care in relation to a national guideline, we conducted a retrospective observational study including CA125 data from a well‐defined region in the UK, from 2003 to 2014. 51,033 CA125 tests from 30,737 women were stratified by month and year of testing, location of test request and patient age. Absolute numbers and rates of testing, rates and proportions of positive and negative tests, and frequencies of single and repeat tests were calculated. Negative binomial and logistic regression were used to test the effect of the guideline's introduction. Primary care testing spiked in the three months following the release of the guideline. However, there was no difference in the increase in testing observed across age groups. The proportion of positive tests decreased over time despite both the rates of positive and negative tests increasing. Retesting and repeat testing were associated with the initial CA125 value with no significant difference between women whose first test was 30–35 and >35 IU/L. Large studies using linked data are required to investigate the impact of increasing CA125 testing on onward intervention and patient outcomes. CA125 guidelines should be refined to avoid over‐investigation in low risk age‐groups. [ABSTRACT FROM AUTHOR]