Qualitative Fecal Immunochemical Tests Research Articles

Qualitative Fecal Immunochemical Test as a Screening Test for Colorectal Cancer

Colorectal cancer is one of the most common cancers, causing mortality, morbidity, and economic burden. Patient survival differs due to differences in access to health facilities, as well as diagnostic and therapeutic modalities. Early detection can allow colorectal cancer to be diagnosed at an earlier stage, improving patient outcomes and lowering mortality. Due to the lack of a national screening program in Indonesia, as well as the uneven availability of colonoscopy tools, the fecal immunochemical test has become the preferred screening method. This cross-sectional study aims to validate the application of the fecal immunochemical test for colorectal cancer detection. Fecal immunochemical test examination is performed on all patients with suspected colorectal cancer who will undergo a colonoscopy examination at Prof. Hospital dr. I.G.N.G. Ngoerah, Bali, Indonesia. Histopathological examination is used to diagnose colorectal cancer. This study included 78 people with a colorectal cancer prevalence of 40.91%. There were 38(57.6%) subjects with positive fecal immunochemical test results in this study, and 25(65.6%) of them were diagnosed with colorectal cancer. The sensitivity, specificity, positive predictive value, and negative predictive value of the qualitative fecal immunochemical test in detecting colorectal cancer were 92.59%, 66.67%, 65.79%, and 92.86%, respectively. The qualitative fecal immunochemical test has high sensitivity and can be used as an objective and accurate method of screening symptomatic patients with suspected CRC for colonoscopy.

A qualitative interview study on colorectal cancer screening in China.

The effectiveness of triage screening for colorectal cancer (CRC) is not fully achieved in Chinese populations, mainly due to low compliance to colonoscopy follow-up. This study aimed to collect viewpoints of experts in China on ongoing screening programs and emerging screening tests for CRC, which may help to improve effectiveness of CRC screening in the country. We conducted 15 semi-structured interviews with experts involving CRC screening in China during October to November of 2020. Interview topics included personal characteristics, work context, opinions on ongoing screening programs, challenges and opportunities in optimization of screening strategies, and prospects for CRC screening in near future. To analyze the data, we used a generic qualitative research approach inspired by grounded theory, including open, axial, and selective coding. This analysis revealed a total of 83 initial categories, 37 subcategories and 10 main categories, which included 4 core categories of current modality for CRC screening, factors influencing screening effectiveness, optimization of CRC screening modality, and prospects for development of CRC screening. The results provide insight into the factors underlying the challenges of the ongoing CRC screening programs in China: the most important concern is the low compliance to colonoscopy, followed by the low specificity of the currently-used initial tests. The experts proposed to use quantitative instead of qualitative fecal immunochemical test (FIT), and optimize risk assessment tools to improve specificity of initial tests. Regarding the emerging screening tests, 9 of 15 experts did not think that the novel techniques are good enough to replace the current tests, but can be used complementarily in opportunistic screening for CRC. The viewpoints of Chinese experts suggested that use quantitative FIT or optimize risk assessment tools may help to identify high-risk individuals of CRC more accurately, improve adherence to colonoscopy, and thus fully achieve the effectiveness of screening.

Cost-Utility Analysis for Colorectal Cancer Screening According to the Initiating Age of National Cancer Screening Program in Korea.

This study aimed to identify the most cost-effective strategy for colorectal cancer screening using the fecal immunochemical test (FIT), focusing on screening initiation age in Korea. We designed Markov simulation models targeting individuals aged 40 years or older. Twelve strategies combining screening initiation ages (40, 45, or 50 years old), termination ages (80 or no limit), and intervals (1 or 2 years) were modeled, and the most cost-effective strategy was selected. The robustness of the results was confirmed using one-way and probabilistic sensitivity analyses. Furthermore, the cost-effectiveness of the qualitative and quantitative FIT methods was verified using scenario analysis. The 2-year interval strategy with a screening age range of 45-80 years was the most cost-effective (incremental cost-utility ratio = KRW 7,281,646/quality adjusted life years). The most sensitive variables in the results were transition rate from advanced adenoma to local cancer and discount rate. The uncertainty in the model was substantially low. Moreover, strategies starting at the age of 40 years were also cost-effective but considered suboptimal. The scenario analysis showed that there was no significant difference in cost-effectiveness between strategies with various relative screening ratio of quantitative and qualitative method. The screening method for advancing the initiation age, as presented in the 2015 revised national screening recommendations, was superior regarding cost-effectiveness. This study provides a new paradigm for the development of a national cancer screening system in Korea, which can be utilized as a scientific basis for economic evaluations.

Colorectal Cancer Screening Pilot Project in Tehran-Iran, a Feasibility Study.

Colorectal cancer (CRC) is the third most common cancer in Iran, where there is no organised CRC-screening programme. This study aimed to evaluate feasibility of CRC screening using a qualitative fecal immunochemical test (FIT) among Iranian average-risk adults. In this feasibility study, 7039 individuals aged 50-75 years were invited by community health workers (CHWs) in southern Tehran and its suburban districts between April 2018 and November 2019. The CHWs performed a qualitative FIT with cut-off level 50 ng Hb/mL buffer and referred those with positive-FIT for colonoscopy to the endoscopy center of Shariati hospital in Tehran. Outcomes included acceptance rate, FIT positivity rate, colonoscopy compliance, detection rates and positive predictive values (PPVs) with 95% confidence interval for CRC and advanced adenomas (AAs). Acceptance rate at initial invitation was 71.7%. From 4974 average-risk adults (1600 males and 3374 females) who were offered FIT, 96.8% (n=4813) provided valid samples, of whom 471 (9.8%) tested positive. Among FIT-positive participants, 150 (31.8%) underwent colonoscopy; CRC was detected in 2.0% (n=3) and adenomas in 27.3% (n=41). Detection rate of CRC and AAs per 1000-FIT-screened participants was 0.6 (0.1-1.8) [males: 0.7 (0.01-3.6), females: 0.6 (0.07-2.0)] and 4.2 (2.5-6.4) [males: 5.9 (2.6-11.0), females: 3.4 (1.7-6.0)], respectively. PPVs were 2.0% (0.4-5.7) for CRC and 13.3% (8.3-19.8) for AAs. There was no association between gender and the studied outcomes. Our results partially support the feasibility of scaling up organized CRC-screening through the existing healthcare system in Iran; it remains to be discussed carefully to ensure the capacity of healthcare system for adequate colonoscopy services.

Colorectal cancer screening in sub-Saharan Africa

Colorectal cancer screening in sub-Saharan Africa

Colorectal cancer screening with fecal immunochemical testing: a community-based, cross-sectional study in average-risk individuals in Nigeria

The estimated incidence of colorectal cancer is rising in Nigeria, where most patients present with advanced disease. Earlier detection of colorectal cancer is a goal of the Nigerian National Cancer Control Plan, but the utility of fecal-based screening is unclear. This study aimed to assess the fecal immunochemical test as a colorectal cancer screening modality in average-risk individualS in Nigeria. A population-based, cross-sectional study of qualitative fecal immunochemical test-based colorectal cancer screening was done in asymptomatic, average-risk participants aged 45-75 years in three states in Nigeria (Osun, Kwara, and Lagos). Participants were invited to enrol using age-stratified and sex-stratified convenience sampling following community outreach. Exclusion criteria included a personal history of colorectal cancer or rectal bleeding in the previous 6 months, a first-degree relative with a known diagnosis of colorectal cancer, or a comorbidity that would preclude conscious sedation or general anesthesia. Participants with positive fecal immunochemical test results underwent colonoscopy, and the positive predictive value of fecal immunochemical testing for colorectal cancer and advanced adenomas (≥10 mm, tubulovillous or villous or high-grade dysplasia) was calculated. Data on demographics and acceptability of fecal immunochemical testing and colonoscopy were collected. Between January and April 2021, 2330 participants were enrolled in the study and received a fecal immunochemical test, which was returned by 2109 participants. 1677 participants tested negative and 432 tested positive. Of these 432 participants, 285 underwent a colonoscopy (235 showed no polyps or cancer, 47 had polyps identified, and three had colorectal cancer identified). Of the 47 participants who had polyps identified, 20 had advanced adenomas diagnosed. The median age was 57 years (IQR 50-63), 958 (41%) were male and 1372 (59%) were female, and 68% had at least a secondary-level education. Participants were evenly spread across wealth quintiles. The positivity rate of the fecal immunochemical test was 21% overall (432 of 2109; 95% CI 20-21%), 11% (51 of 455; 95% CI 10-12) in Lagos, 20% (215 of 1052; 95% CI 20-21) in Osun, and 28% (166 of 597; 95% CI 27-29) in Kwara. Among the patients with a positive fecal immunochemical test who completed colonoscopy, the positive predictive value for invasive colorectal cancer was 1·1% (95% CI 0·3-3·3), and 7·0% (4·5-10·8) for advanced adenoma. The acceptability of fecal immunochemical screening among participants was very high. Colorectal cancer screening with qualitative fecal immunochemical tests in Nigeria is feasible and acceptable to average-risk asymptomatic participants. However, the low positive predictive value for advanced neoplasia and high endoscopy burden investigating false positives suggests it might not be an appropriate screening tool in this setting. Thompson Family Foundation, Prevent Cancer Foundation, National Institutes of Health/National Cancer Institute Program Cancer Center.

Replicate and repeat faecal immunochemical tests in symptomatic patients: A systematic review.

Faecal Immunochemical tests (FITs) in the assessment of patients presenting with symptoms have generally used a single sample. Little evidence pertains to the use of replicate, where a number of tests are done prior to decision-making or repeat FIT, where additional FIT are performed following clinical decision-making. Overwhelmingly, research has focussed on FIT to help identify colorectal cancer (CRC). The aim of this review is to assess the available literature concerning replicate and repeat FIT in symptomatic patients to help generate consensus and guide future research. The terms 'faecal immunochemical test' or 'FIT' were combined with 'multiple' or 'repeat'. EMBASE, Medline and PubMed database and other searches were conducted. All papers published in English were included with no exclusion date limits until November 2021. Of the 161 initial papers screened, seven were included for review. Qualitative and quantitative FIT outcomes were assessed in the studies. The primary aims of most related to whether replicate FIT increased diagnostic yield of CRC, with colonoscopy used as the reference standard. One publication assessed the impact of a new COVID-adapted pathway on CRC detection. No consensus on replicate FIT was apparent. Some concluded that FITs may help minimise missed CRC diagnoses: others showed no increase in diagnostic yield of CRC. Current evidence on replicate and repeat FIT is both minimal and conflicting. FIT is a superb clinical tool, but significant gaps surrounding application remain. Further studies relating to replicate and repeat FIT are required.

One-sample quantitative and two-sample qualitative faecal immunochemical tests for colorectal cancer screening: a cross-sectional study in China

ObjectivesQuantitative faecal immunochemical tests (FITs) are widely used for colorectal cancer (CRC) screening in the Western countries, whereas qualitative FITs are preferred in China. The present study aimed to compare...

Adherence to colonoscopy in cascade screening of colorectal cancer: A systematic review and meta‐analysis

This study aims to systematically evaluate adherence to colonoscopy and related factors in cascade screening of colorectal cancer (CRC) among average-risk populations, which is crucial to achieve the effectiveness of CRC screening. We searched PubMed, Embase, Web of Science, and Cochrane Library for studies published in English up to October 16, 2020, and reporting the adherence to colonoscopy following positive results of initial screening tests. A random-effects meta-analysis was applied to estimate pooled adherence and 95% confidence intervals. Subgroup analysis and mixed-effects meta-regression analysis were performed to evaluate heterogeneous factors for adherence level. A total of 245 observational and 97 experimental studies were included and generated a pooled adherence to colonoscopy of 76.6% (95% confidence interval: 74.1-78.9) and 80.4% (95% confidence interval: 77.2-83.1), respectively. The adherence varied substantially by calendar year of screening, continents, CRC incidence, socioeconomic status, recruitment methods, and type of initial screening tests, with the initial tests as the most modifiable heterogeneous factor for adherence across both observational (Q=162.6, P<0.001) and experimental studies (Q=23.2, P<0.001). The adherence to colonoscopy was at the highest level when using flexible sigmoidoscopy as an initial test, followed by using guaiac fecal occult blood test, quantitative or qualitative fecal immunochemical test, and risk assessment. The pooled estimate of adherence was positively associated with specificity and positive predictive value of initial screening tests, but negatively with sensitivity and positivity rate. Colonoscopy adherence is at a low level and differs by study-level characteristics of programs and populations. Initial screening tests with high specificity or positive predictive value may be followed by a high adherence to colonoscopy.

Feasibility and performance of the fecal immunochemical test (FIT) for average-risk colorectal cancer screening in Nigeria.

There is a paucity of prospective data on the performance of the fecal immunochemical test (FIT) for colorectal cancer (CRC) screening in sub-Saharan Africa. The aim of this exploratory analysis was to evaluate the feasibility and performance of FIT in Nigeria. This was a prospective, single-arm study. A convenience sample of asymptomatic, average-risk individuals between 40-75 years of age were enrolled at Obafemi Awolowo University Teaching Hospital. Study participants returned in 48 hours with a specimen for ova and parasite (O&P) and qualitative FIT (50ug/g) testing. Participants with a positive FIT had follow-up colonoscopy and those with intestinal parasites were provided treatment. Between May-June 2019, 379 individuals enrolled with a median age of 51 years (IQR 46-58). In total, 87.6% (n = 332) returned for FIT testing. FIT positivity was 20.5% (95% CI = 16.3%-25.2%). Sixty-one (89.7%) of participants with a positive FIT had a follow-up colonoscopy (n = 61), of whom 9.8% (95%CI:3.7-20.2%) had an adenoma and 4.9% (95%CI:1.0-13.7%) had advanced adenomas. Presence of intestinal parasites was inversely related to FIT positivity (6.5% with vs. 21.1% without parasites, p = 0.05). Eighty-two percent of participants found the FIT easy to use and 100% would recommend the test to eligible family or friends if available. Asymptomatic, FIT-based CRC screening was feasible and well tolerated in this exploratory analysis. However, the high FIT positivity and low positive predictive value for advanced neoplasia raises concerns about its practicality and cost effectiveness in a low-resource setting such as Nigeria.

Divergent detection rates of fecal immunochemical test and questionnaire-based risk assessment for detecting proximal and distal advanced colorectal adenomas

Divergent detection rates of fecal immunochemical test and questionnaire-based risk assessment for detecting proximal and distal advanced colorectal adenomas

Diagnosing colorectal cancer in primary care: cohort study in Sweden of qualitative faecal immunochemical tests, haemoglobin levels, and platelet counts.

BackgroundColorectal cancer (CRC) diagnostics are challenging in primary care and reliable diagnostic aids are desired. Qualitative faecal immunochemical tests (FITs) have been used for suspected CRC in Sweden since the mid-2000s, but evidence regarding their effectiveness is scarce. Anaemia and thrombocytosis are both associated with CRC.AimTo evaluate the usefulness of qualitative FITs requested for symptomatic patients in primary care, alone and combined with findings of anaemia and thrombocytosis, in the diagnosis of CRC.Design and settingA population-based cohort study using electronic health records and data from the Swedish Cancer Register, covering five Swedish regions.MethodPatients aged ≥18 years in the five regions who had provided FITs requested by primary care practitioners from 1 January 2015 to 31 December 2015 were identified. FIT and blood-count data were registered and all CRC diagnoses made within 2 years were retrieved. Diagnostic measurements were calculated.ResultsIn total, 15 789 patients provided FITs (four different brands); of these patients, 304 were later diagnosed with CRC. Haemoglobin levels were available for 13 863 patients, and platelet counts for 10 973 patients. Calculated for the different FIT brands only, the sensitivities for CRC were 81.6%–100%; specificities 65.7%–79.5%; positive predictive values 4.7%–8.1%; and negative predictive values 99.5%–100%. Calculated for the finding of either a positive FIT or anaemia, the sensitivities increased to 88.9–100%. Adding thrombocytosis did not further increase the diagnostic performance.ConclusionQualitative FITs requested in primary care seem to be useful as rule-in tests for referral when CRC is suspected. A negative FIT and no anaemia indicate a low risk of CRC.

Qualitative faecal immunochemical tests (FITs) for diagnosing colorectal cancer in patients with histories of rectal bleeding in primary care: a cohort study

BackgroundRectal bleeding is considered an alarm symptom for colorectal cancer (CRC) but it is common and mostly caused by benign conditions. Qualitative faecal immunochemical tests (FITs) for occult blood have been used as diagnostic aids for many years in Sweden when CRC is suspected. The study aimed to evaluate the usefulness of FITs requested by primary care physicians for patients with and without histories of rectal bleeding, in the diagnosis of CRC.MethodsResults of all FITs requested in primary care for symptomatic patients in the Örebro region during 2015 were retrieved. Data on each patient’s history of rectal bleeding was gathered from electronic health records. Patients diagnosed with CRC within 2 years were identified from the Swedish Cancer Register. The analysis focused on three-sample FITs, the customary FIT in Sweden.ResultsA total of 4232 patients provided three-sample FITs. Information about the presence/absence of rectal bleeding was available for 2027 patients, of which 59 were diagnosed with CRC. For 606 patients with the presence of rectal bleeding, the FIT showed sensitivity 96.2%, specificity 60.2%, positive predictive value 9.8% (95% CI 6.1–13.4) and negative predictive value 99.7% (95% CI 99.2–100) for CRC. For 1421 patients without rectal bleeding, the corresponding figures were 100%, 73.6%, 8.3% (95% CI 5.6–10.9) and 100% (95% CI 99.6–100).ConclusionThe diagnostic performance of a qualitative three-sample FIT provided by symptomatic patients in primary care was similar for those with and without a history of rectal bleeding. FITs seem useful for prioritising patients also with rectal bleeding for further investigation.

An Exploratory Analysis of Fecal Immunochemical Test Performance for Colorectal Cancer Screening in Nigeria.

The fecal immunochemical test (FIT) for hemoglobin is recommended for colorectal cancer (CRC) screening in resource-limited environments. However, there are several unique variables that may alter FIT performance in this setting, including endemic intestinal parasites and high ambient temperature. This prospective study evaluated the performance of FIT in asymptomatic, average-risk individuals of screening age in rural Nigeria. Three hundred and twenty-four community volunteers completed a questionnaire and provided stool specimens for parasitology and microbiome analysis. Specimens were frozen and stored at -80°C. Of 324 subjects, 139 met criteria for average-risk CRC screening and had a stool sample for analysis. These were thawed and tested with a qualitative FIT. Specimens positive for occult blood were retested every two days to evaluate the impact of time and temperature on test performance. Of 139 individuals, 69 (49.6%) were positive for intestinal parasites and 10 (7.2%) were positive for occult blood. The most common pathogen was Cryptosporidium (40.6%). Among patients with intestinal parasites, 10.1% (7/69) had a positive FIT. Only 4.3% (3/70) of patients without parasites had a positive FIT (p = 0.208). On bivariate analysis, sociodemographic variables were not associated with a positive FIT result. Thirty percent (3/10) of the FIT-positive specimens became FIT-negative with routine storage. Although a positive FIT result was more common in those with parasitic infection, the relationship was not significant in this small cohort. The impact of high ambient temperature on test positivity may necessitate shorter processing time guidelines for equatorial countries. Additional prospective studies are needed to validate FIT performance in Nigeria.

Improvement in External Quality Assessment Results for Qualitative Fecal Immunochemical Tests in Korea After Feedback to Manufacturers.

Wonmok Lee , M.D., Nanhee Ryoo , M.D., Hun-Seok Suh , M.D., and Chang-Ho Jeon , M.D.; Urinalysis and Routine Microscopy Subcommittee, Korean Association of External Quality Assessment Service. Ann Lab Med 2019;39:584-6. https://doi.org/10.3343/alm.2019.39.6.584

Colorectal Cancer Screening Modalities in Chinese Population: Practice and Lessons in Pudong New Area of Shanghai, China.

Background: Parallel test of risk stratification and two-sample qualitative fecal immunochemical tests (FITs) are used to screen colorectal cancer (CRC) in Shanghai, China. This study was designed to identify an optimal initial screening modality based on available data.Methods: A total of 538,278 eligible residents participated in the program during the period of January 2013 to June 2017. Incident CRC was collected through program reporting system and by record linkage with the Shanghai Cancer Registry up to December 2017. Logistic regression model was applied to identify significant factors to calculate risk score for CRC. Cutoff points of risk score were determined based on Youden index and defined specificity. Sensitivity, specificity, and positive predictive values (PPVs) were computed to evaluate validity of assumed screening modalities.Results: A total of 446 CRC were screen-detected, and 777 interval or missed cases were identified through record linkage. The risk score system had an optimal cutoff point of 19 and performed better in detecting CRC and predicting long-term CRC risk than did the risk stratification. When using a cutoff point of 24, parallel test of risk score, and FIT were expected to avoid 56 interval CRCs with minimal decrease in PPV and increase in colonoscopy. However, the observed detection rates were much lower than those expected due to low compliance to colonoscopy.Conclusions: Risk score is superior to risk stratification used in the program, particularly when combined with FIT. Compliance to colonoscopy should be improved to guarantee the effectiveness of CRC screening in the population.

Performance Characteristics of Fecal Immunochemical Tests for Colorectal Cancer and Advanced Adenomatous Polyps: A Systematic Review and Meta-analysis.

Studies report inconsistent performance of fecal immunochemical tests (FITs) for colorectal cancer (CRC) and advanced adenomas. To summarize performance characteristics of FITs for CRC and advanced adenomas in average-risk persons undergoing screening colonoscopy (reference standard) and to identify factors affecting these characteristics. Ovid MEDLINE, PubMed, Embase, and the Cochrane Library from inception through October 2018; reference lists of studies and reviews. Two reviewers independently screened records to identify published English-language prospective or retrospective observational studies that evaluated FIT sensitivity and specificity for colonoscopic findings in asymptomatic, average-risk adults. Two authors independently extracted data and evaluated study quality. Thirty-one studies (120255 participants; 18 FITs) were included; all were judged to have low to moderate risk of bias. Performance characteristics depended on the threshold for a positive result. A threshold of 10 µg/g resulted in sensitivity of 0.91 (95% CI, 0.84 to 0.95) and a negative likelihood ratio of 0.10 (CI, 0.06 to 0.19) for CRC, whereas a threshold of greater than 20 µg/g resulted in specificity of 0.95 (CI, 0.94 to 0.96) and a positive likelihood ratio of 15.49 (CI, 9.82 to 22.39). For advanced adenomas, sensitivity was 0.40 (CI, 0.33 to 0.47) and the negative likelihood ratio was 0.67 (CI, 0.57 to 0.78) at 10 µg/g, and specificity was 0.95 (CI, 0.94 to 0.96) and the positive likelihood ratio was 5.86 (CI, 3.77 to 8.97) at greater than 20 µg/g. Studies had low to high heterogeneity, depending on the threshold. Although several FITs had adequate performance, sensitivity and specificity for CRC for 1 qualitative FIT were 0.90 and 0.91, respectively, at its single threshold of 10 µg/g; positive and negative likelihood ratios were 10.13 and 0.11, respectively. Comparison of 3 FITs at 3 thresholds was inconclusive: CIs overlapped, and the comparisons were across rather than within studies. Only English-language studies were included. Incomplete reporting limited quality assessment of some evidence. Performance characteristics are for 1-time rather than serial testing. Single-application FITs have moderate to high sensitivity and specificity for CRC, depending on the positivity threshold. Sensitivity of 1-time testing for advanced adenomas is low, regardless of the threshold. Department of Medicine, Indiana University School of Medicine.

The importance of comparing quantitative faecal immunochemical tests (FIT) before selecting one for a population-based colorectal cancer screening programme

FIT for haemoglobin are now commonly used in many countries as the best, currently available, non-invasive test for colorectal cancer (CRC) in asymptomatic population screening programmes (1). FIT are available in two formats, qualitative, usually based on lateral-flow immunochromatographic test strips or cassettes, and quantitative, most often based on immunoturbidimetry, and performed on small benchtop analyzers. Quantitative FIT have a number of significant advantages over qualitative FIT, a major one being that analyses of faecal samples give estimates of the faecal haemoglobin concentrations (f-Hb) (2).

Optimizing sampling device for the fecal immunochemical test increases colonoscopy yields in colorectal cancer screening.

The fecal immunochemical test (FIT) that quantifies hemoglobin concentration is reported to be better than qualitative FIT and the reason for its superiority has not been interpreted. To evaluate and understand the superiority of quantitative FIT, a representative randomly selected population (n=2355) in Jiashan County, China, aged 40-74 years was invited for colorectal cancer screening in 2012. Three fecal samples were collected from each participant by one optimized and two common sampling devices, and then tested by both quantitative and qualitative FITs. Colonoscopy was provided independently to all participants. The performances of five featured screening strategies were compared. A total of 1020 participants were eligible. For screening advanced neoplasia, the positive predictive value (PPV) and the specificity of the strategy that tested one sample dissolved in an optimized device by quantitative FIT [PPV=40.8%, 95% confidence interval (CI): 27.1-54.6; specificity=96.8%, 95% CI: 95.7-98.0] were significantly improved over the strategy that tested one sample dissolved in the common device by qualitative FIT (PPV=14.1%, 95% CI: 8.2-19.9; specificity=87.9%, 95% CI: 85.8-89.9), whereas the sensitivity did not differ (39.2 and 37.3%, P=0.89). Similar disparity in performance was observed between the strategies using qualitative FIT to test one sample dissolved in optimized (PPV=29.5%, 95% CI: 18.1-41.0; specificity=95.3%, 95% CI: 94.0-96.7) versus common sampling devices. High sensitivity for advanced neoplasia was observed in the strategy that tested two samples by qualitative FIT (52.9%, 95% CI: 39.2-66.6). Quantitative FIT is better than qualitative FIT for screening advanced colorectal neoplasia. However, the fecal sampling device might contribute most significantly toward the superiority of quantitative FIT.

Effect of Ambient Temperature Variations on Positivity of Manual Fecal Immunochemical Tests.

In the United States, many fecal occult blood tests are mailed by patients to a laboratory for analysis. Hemoglobin is not stable in feces and can be affected by the heat. Effects of season and ambient temperature on fecal immunochemical tests (FITs) have demonstrated a decrease in positivity rates during the hottest season. To investigate the potential effect of the average of 4-day ambient maximum temperature variations on the positivity of a single sample, one-time Clinical Laboratory Improvement Amendments (CLIA)-waived FIT. Midwestern tertiary care hospital. Individuals scheduled for a colonoscopy were invited to complete a qualitative FIT prior to their colonoscopy in 2010 and 2011. FITs were read as positive or negative. Valid FITs were received from 1026 individuals over 25 months. The positivity rate was 10.9%. The mean 4-day average of daily maximum ambient temperatures was calculated including the day of receipt for each sample. Fahrenheit temperatures ranged from 16.0 to 96.8. Based on the odds ratio of 1.04 with a confidence interval of 0.94 to 1.14 for a 10°F increase in temperature, there was no statistically significant evidence of an effect of the preceding maximum average 4-day ambient temperature on FIT positivity. No evidence was found that ambient temperature had an effect on positivity rate over a 25-month period using 4 different qualitative FIT products. Further analysis on effect of ambient temperatures is warranted for the automated FITs and CLIA-waived FITs, including liquid-vial and dry-slide FITs. Primary care providers need to be aware of potential adverse effects of FITs.