Fecal Calprotectin Measurement Research Articles

Fecal calprotectin: beyond intestinal organic diseases.

Fecal calprotectin (FC) is a calcium-binding protein with antimicrobic, imunomodulatory and antiproliferative properties that is mainly found in the cytoplasm of neutrophil granulocytes. During the last decades, FC became an increasingly useful tool both for gastroenterologists and for general practitioners for distinguishing inflammatory bowel disease (IBD) from irritable bowel syndrome. FC correlates with clinical scoring systems and endoscopic lesions in IBD and is considered a reliable biomarker for the prediction of clinical relapse or remission. However, FC elevation could be observed also in other gastrointestinal pathological conditions including infective colitis, microscopic colitis, eosinophilic colitis, adenomas and colorectal cancer. In addition, there are several non-pathological conditions that can lead to altered FC values. In this review, we aimed to point out individual, environmental and method-related factors that can affect FC measurement and thus its clinical interpretation.

P329 Utility of faecal calprotectin to assess Crohn’s disease activity in patients with an ileostomy

Faecal calprotectin (FCP) is increasingly used as a non-invasive tool to monitor ulcerative colitis. However, to date the use of FCP to monitor patients with an ileostomy due to Crohn’s disease (CD) has not been established. The aim of this study was to assess the performance characteristics of FCP in patients with Crohn’s disease and an ileostomy. Patients with an ileostomy due to CD, attending a single academic centre were identified. Patient demographics were recorded using a prospectively maintained database of >3800 IBD patients. Endoscopy activity was graded using modified Rutgeert’s score. Radiological investigations included MRE/CT, and classified as active or inactive CD. Seventeen patients were identified. Patient demographics, disease characteristics, and baseline biochemistry are given in Table 1. Patient demographics and disease characteristics Patient demographics and disease characteristics A total of 19 contemporaneous endoscopic and FCP results from 15 patients were analysed. 63.2% had i0/1 disease, 15.7% i2, and 21.1% i3/i4. Furthermore, no significant correlation was identified between endoscopic scores and FCP results (R = 0.312; p = 0.19). The median FCP result for those patients with i0/i1 disease was 139.5 μg/g (IQR 41.25–232), while those with i2–i4 disease activity had a median FCP of 426 μg/g (IQR 44.75–2284.5). There was no significant difference between these two groups (p = 1.00). Five patients underwent radiological and FCP assessment simultaneously. There was no significant correlation identified (R = 0.866; p = 0.33). The utility of FCP to detect endoscopic activity was assessed. An FCP of 117.5 μg/g had a sensitivity of 67% and specificity of 63%; AUROC = 0.75 (Figure 1). Sensitivity and specificity of FCP to detect disease activity (AUROC) In this study, there was poor correlation between FCP and established tools in assessing disease activity. FCP measurement alone has only moderate sensitivity/specificity for the detection of disease activity in patients with CD and an ileostomy. FCP is best utilised in conjunction with other objective tools in this particular patient cohort as it is not a reliable independent non-invasive marker of disease activity.

Serial semi-quantitative measurement of fecal calprotectin in patients with ulcerative colitis in remission

Background: Fecal calprotectin (FC) correlates with clinical and endoscopic activity in ulcerative colitis (UC), and it is a good predictor of relapse. However, its use in clinical practice is constrained by the need for the patient to deliver stool samples, and for their handling and processing in the laboratory. The availability of hand held devices might spread the use of FC in clinical practice.Objectives: To evaluate the usefulness of a rapid semi-quantitative test of FC in predicting relapse in patients with UC in remission.Materials and methods: Prospective, multicenter study that included UC patients in clinical remission for ≥6 months on maintenance treatment with mesalamine. Patients were evaluated clinically and semi-quantitative FC was measured using a monoclonal immunochromatography rapid test at baseline and every three months until relapse or 12 months of follow-up.Results: One hundred and ninety-one patients had at least one determination of FC. At the end of follow-up, 33 patients (17%) experienced clinical relapse. Endoscopic activity at baseline (p = .043) and having had at least one FC > 60 μg/g during the study period (p = .03) were associated with a higher risk of relapse during follow-up. We obtained a total of 636 semi-quantitative FC determinations matched with a three-month follow-up clinical assessment. Having undetectable FC was inversely associated with early relapse (within three months), with a negative predictive value of 98.6% and a sensitivity of 93.9%.Conclusions: Serial, rapid semi-quantitative measurement of FC may be a useful, easy and cheap monitoring tool for patients with UC in remission.

Fecal calprotectin measurement is a marker of short-term clinical outcome and presence of mucosal healing in patients with inflammatory bowel disease.

AIMTo evaluate the utility of fecal calprotectin (FC) in predicting relapse and endoscopic activity during follow-up in an inflammatory bowel disease (IBD) cohort.METHODSAll FC measurements that were obtained during a 3-year period from patients with inflammatory bowel disease in clinical remission were identified. Data regarding the short-term (6 mo) course of the disease were extracted from the medical files. Exclusion criteria were defined as: (1) An established flare of the disease at the time of FC measurement, (2) Loss to follow up within 6 mo from baseline FC measurement, and, (3) Insufficient data on file. Statistical analysis was performed to evaluate whether baseline FC measurement could predict the short term clinical relapse and/or the presence of mucosal healing.RESULTSWe included 149 [Crohn’s disease (CD) = 113, Ulcerative colitis (UC) = 36, male = 77] IBD patients in our study. Within the determined 6-month period post-FC measurement, 47 (31.5%) had a disease flare. Among 76 patients who underwent endoscopy, 39 (51.3%) had mucosal healing. Baseline FC concentrations were significantly higher in those who had clinical relapse compared to those who remained in remission during follow up (481.0 μg/g, 286.0-600.0 vs 89.0, 36.0-180.8, P < 0.001). The significant predictive value of baseline median with IQR FC for clinical relapse was confirmed by multivariate Cox analysis [HR for 100μg/g: 1.75 (95%CI: 1.28-2.39), P = 0.001]. Furthermore, lower FC baseline values significantly correlated to the presence of mucosal healing in endoscopy (69.0 μg/g, 30.0-128.0 vs 481.0, 278.0-600.0, in those with mucosal inflammation, median with IQR, P < 0.001). We were able to extract cut-off values for FC concentration with a high sensitivity and specificity for predicting clinical relapse (261 μg/g with AUC = 0.901, sensitivity 87.2%, specificity 85.3%, P < 0.001) or mucosal healing (174 μg/g with AUC = 0.956, sensitivity 91.9%, specificity 87.2%, P < 0.001). FC was better than CRP in predicting either outcome; nevertheless, having a pathological CRP (> 5 mg/L) in addition to the cut-offs for FC, significantly enhanced the specificity for predicting clinical relapse (95.1% from 85.3%) or endoscopic activity (100% from 87.2%).CONCLUSIONSerial FC measurements may be useful in monitoring IBD patients in remission, as FC appears to be a reliable predictor of short-term relapse and endoscopic activity.

Cannabis for the treatment of Crohn's disease

Cannabis for the treatment of Crohn's disease

Analytical evaluation of a fully automated immunoassay for faecal calprotectin in a paediatric setting.

IntroductionFaecal calprotectin (FC) is a routinely used marker for identifying and monitoring children with inflammatory bowel disease (IBD). This non-invasive test is useful for screening children with gastrointestinal symptoms to avoid unnecessary invasive procedures. In this study, we validated for the first time the performance of a fully automated particle-enhanced turbidimetric immunoassay (PETIA) on the VITROS® 5600 analyzer for measurement of FC in symptomatic children and adolescents.Materials and methodsFor performance validation of the PETIA (fCAL® turbo, Bühlmann Laboratories, Switzerland) on the VITROS® 5600 analyzer (Ortho Clinical Diagnostics, USA) limit of quantitation (LoQ), linearity, precision data and calibration curve stability were defined. Additionally, 95 faecal samples were measured using the PETIA, an enzyme-linked immunosorbent assay (ELISA; fCAL®, Bühlmann Laboratories, Switzerland) and a semi-quantitative lateral flow assay (Quantum Blue Reader®, Bühlmann Laboratories, Switzerland) for agreement evaluation.ResultsThe LoQ for calprotectin using PETIA on the VITROS® 5600 analyzer was 21 µg/g. The linearity range was 20 - 2100 µg/g and the precision study showed a total coefficient of variation (CV) between 2.3% and 8.9%. The calibration curve was stable for 4 weeks. Using the clinical samples quantifiable by PETIA, ELISA and the semi-quantitative lateral flow assay, Passing-Bablok regression analysis and Bland-Altman plots showed good agreement.ConclusionsDue to good performance characteristics and agreement with established methods, the fully automated PETIA on the routine chemistry analyzer VITROS® 5600 is a new analytical option for the rapid determination of FC.

Fecal Calprotectin in Cystic Fibrosis and Its Relation to Disease Parameters: A Longitudinal Analysis for 12 Years.

Fecal calprotectin (FC) is a marker of inflammation in the intestinal tract. We assessed FC levels longitudinally in patients with cystic fibrosis (CF) and evaluated the relation between FC results and relevant markers of disease. Calprotectin was measured in fecal samples starting in 2003 and values were stored in the center's patient database. In this retrospective analysis, we searched for associations of FC concentrations with disease severity and progression. Linear mixed effects models were used to model the logarithm of FC levels. A total of 171 patients (0-61 years) had 2434 FC measurements between 2003 and 2015, with a total observation period of 1686 patient-years. Median (interquartile range) FC concentrations were 60.9 (75.9) μg/g and 61% of the samples showed elevated FC concentrations (>50 μg/g). Despite some statistically significant effects, there was no clinically relevant association among FC and sex, age, forced expiratory volume in 1 second z score, or body mass index z score. Pancreatic insufficiency (ie, fecal elastase <100 μg/g stool) was associated with considerably higher FC values compared to normal pancreatic function (median FC 68 vs 29 μg/g, P < 0.0001). F508del homozygous subjects showed a trend to higher FC values than heterozygous patients (median 71 vs 62 μg/g, P = 0.173). In addition, a significant association with increasing serum C-reactive protein concentrations (P < 0.0001) was observed. FC was elevated in two-thirds of stool specimens. Increased FC was more common in patients with pancreatic insufficiency. Whether increased FC reflects intestinal inflammation in patients with CF remains to be determined.

Simultaneous Measurements of Faecal Calprotectin and the Faecal Immunochemical Test in Quiescent Ulcerative Colitis Patients Can Stratify Risk of Relapse.

Both faecal calprotectin [Fcal] and the faecal immunochemical test [FIT] are useful to predict clinical relapse of ulcerative colitis [UC]. However, the difference between Fcal and FIT in ability to predict relapse has scarcely been reported. Whether the combined use of these two faecal markers increases the predictability is also unknown. UC patients in clinical remission who underwent colonoscopy were enrolled prospectively, and the Fcal and FIT values were examined at enrolment. Their clinical course was observed for 2 years or until relapse. The correlation between the incidence of relapse and the values of the two markers was examined. A total of 113 patients were enrolled, and 48 [42%] relapsed. Fcal ≥ 75 μg/g and FIT ≥ 110 ng/mL were defined as Fcal-positive and FIT-positive, respectively, according to the receiver operating characteristic curves. Both Fcal-positive and FIT-positive statuses were independent predictive factors of clinical relapse (hazard ratio [HR] 2.29; 95% confidence interval [CI], 1.23-4.49; p = 0.0086, and HR 2.91; 95% CI, 1.49-5.50; p = 0.0022, respectively). Categorisation of patients into three groups according to the faecal marker status [FIT-positive, FIT-negative and Fcal-positive, and both negative] can efficiently stratify the risk of relapse with graded increases in risk [FIT-negative and Fcal-positive: HR 2.05; 95% CI, 1.02-4.43; p = 0.0045, and FIT-positive: HR 5.43; 95% CI, 2.57-11.76; p < 0.0001, compared with both negative]. Fcal vs FIT showed distinct properties regarding the prediction of relapse in UC. A risk assessment using both faecal markers could increase the predictability for relapse.

Do not forget about pre-analytics in faecal calprotectin measurement!

Do not forget about pre-analytics in faecal calprotectin measurement!

FECAL CALPROTECTIN AND CRP AS BIOCHEMICAL MARKERS IN PREDICTING INFLAMMATORY BOWEL DISEASE ACTIVITY IN PATIENTS WITH ULCERATIVE COLITIS

Background & Aims: The routinely used clinical activity indices alongside systemic markers of inflammation as white blood count (WBC) and erythrocyte sedimentation rate (ESR), have low sensitivity and specificity in the discrimination between inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). These limitations emphasize the need for a sensitive and specific non-invasive marker of bowel inflammation. The aim of the study was to evaluate fecal calprotectin (FC) and C-reactive protein (CRP) as biochemical markers in predicting IBD activity in patients with ulcerative colitis (UC).Patients & Methods: The study included 50 patients with UC aged ranged from 12-74 years. All patients were subjected to full colonoscopy. Ileum was visualized. Each of 5 colonic segments was assessed using endoscopic component of the Mayo score. Colonic biopsies were taken from the suspected lesions for histopathological studies. Blood and stool samples were performed for both CRP and calprotectin respectively.Results: Patients with mild activity had mean age 43.2, mean calprotectin 207.46, and mean C-reactive protein was 11.37. While in moderate to severe group, the mean age was 42.5, mean calprotectin 729.85 and mean CRP was 29.38. Fecal calprotectin (FC) cut off 47.5, sensitivity 84.6%, and specificity 54% and C-reactive protein cut off 7, sensitivity 84%, and specificity of 50% in prediction of moderate to severe activity of IBD.Conclusions: Serial measurements of FC and CRP could be recommended for patients with UC to assess disease activity, induction and maintenance of remission, response to treatment, and recurrence of activity. Keywords: Inflammatory bowel disease (IBD); Irritable bowel syndrome (IBS); Fecal calprotect in (FC); C-reactive protein (CRP); Activity.

Commentary: Impact of Fecal Calprotectin Measurement on Decision-Making in Children with Inflammatory Bowel Disease.

Commentary: Impact of Fecal Calprotectin Measurement on Decision-Making in Children with Inflammatory Bowel Disease.

Clinical Utility of Fecal Calprotectin Monitoring in Asymptomatic Patients with Inflammatory Bowel Disease: A Systematic Review and Practical Guide.

In asymptomatic patients with inflammatory bowel disease (IBD), "monitoring" involves repeated testing aimed at early recognition of disease exacerbation. We aimed to determine the usefulness of repeated fecal calprotectin (FC) measurements to predict IBD relapses by a systematic literature review. An electronic search was performed in Medline, Embase, and Cochrane from inception to April 2016. Inclusion criteria were prospective studies that followed patients with IBD in remission at baseline and had at least 2 consecutive FC measurements with a test interval of 2 weeks to 6 months. Methodological assessment was based on the second Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) checklist. A total of 1719 articles were identified; 193 were retrieved for full text review. Six studies met eligibility for inclusion. The time interval between FC tests varied between 1 and 3 months. Asymptomatic patients with IBD who had repeated FC measurements above the study's cutoff level had a 53% to 83% probability of developing disease relapse within the next 2 to 3 months. Patients with repeated normal FC values had a 67% to 94% probability to remain in remission in the next 2 to 3 months. The ideal FC cutoff for monitoring could not be identified because of the limited number studies meeting inclusion criteria and heterogeneity between selected studies. Two consecutively elevated FC values are highly associated with disease relapse, indicating a consideration to proactively optimize IBD therapy plans. More prospective data are necessary to assess whether FC monitoring improves health outcomes.

Usability of a home-based test for the measurement of fecal calprotectin in asymptomatic IBD patients

The aim of our work was to test the usability of fecal calprotectin (FC) home-based test in inflammatory bowel disease (IBD) patients. MethodsIBD patients were prospectively recruited. They had to measure FC with a dedicated tool and smartphone application, 5 times at two weeks intervals over an 8 weeks period. They had to fill in a usability questionnaire at the first and the last FC measurement. A System Usability Scale (SUS: 0–100) and the Global Score of Usability (GSU: 0–85) were calculated. FC was also centrally measured by ELISA. ResultsFifty-eight patients were recruited. Forty-two performed at least one FC measurement and 27 performed all the FC requested measurements. The median (IQR) SUS (0–100) at the first and last use were 85 (78–90) and 81 (70–88), respectively; the median (IQR) GSU (0–85) at the first and last use were 74 (69–80) and 77 (68–83), respectively. Adherence to the planned measurements and usability of the tool were higher in females and in less severe disease. The intra-class correlation coefficient between home-based and centrally measured FC was 0.88. ConclusionThe adherence to home-based measurement of FC was fair. Usability scores for the home-based test were high. There was a good correlation with the centrally measured FC by ELISA.

32 Does faecal calprotectin measurement have an impact on patient management

Background Faecal calprotectin (FC) is recommended to support the differential diagnosis of IBD or IBS in adults with recent onset lower gastrointestinal symptoms. FC can assess IBD activity in those with known disease, as a rising level is an early marker of potential relapse. There is presently no formal funding for FC within Northern Ireland. Aim To assess if FC measurement directs an immediate modification in patient management within two out-patient groups: 1) new patients with differential diagnosis of IBS or IBD; 2) review patients with known IBD. Method A random selection of FC results from secondary care patients over 12 months were analysed. Patient outcomes following the FC result stratified patients into one of four groups: Discharged, colonoscopy performed, clinic review or escalation of medical therapy. Results Group 1 (n=28): 8 positive FC, all proceeding to endoscopy. In the 14 negative FC, 12 patients were discharged, 2 had clinic review. For indeterminate result: one patient with 2 indeterminate results underwent colonoscopy; 4 had clinic review; 1 was discharged. Group 2 (n=28): of the 20 positive results, 11/20 (55%) had medical management escalated, 5/20 (25%) underwent colonoscopy and 20% had clinic review. In the negative and indeterminate results: 7/8 had clinic review. Conclusions For patients with suspected IBS, a negative FC avoided unnecessary colonoscopy. In patients with known IBD, a raised FC led to an escalation in therapy in the majority of patients to minimise the risk of relapse and potential hospital admission. This study supports the need for a Northern Ireland FC service.

Correlation between fecal calprotectin and inflammation in the surgical specimen of Crohn's disease

BackgroundAn accurate assessment of the inflammatory activity is crucial to establish the most appropriate treatment in Crohn's disease (CD). The present study aimed to evaluate the utility of preoperative fecal calprotectin (FC) measurement in small bowel CD and its relationship with inflammatory activity in surgical pathology specimens. MethodsThis was a prospective observational study including all the patients with small bowel CD operated on at our center between March 2011 and September 2013. Preoperative laboratory and stool tests were performed. A meticulous exploration of entire small bowel was performed during surgery, and the resected bowel (or a sample of whole intestinal wall, if strictureplasty) was submitted for pathologic analyses. Chiorean's score was used to grade pathologic features (inflammation or fibrosis). In case of multiple lesions, the most inflammatory component was considered. ResultsThirty-eight consecutive patients were included in the study, and 81 small bowel lesions were identified. Among inflammatory markers, only FC was significantly associated with the degree of histologic inflammation in the surgical specimen (P < 0.003). FC reflected histologic inflammatory activity with an area under the receiver-operating characteristic curve of 0.85 (CI: 0.70-0.99; P < 0.001). A cutoff value of 170 μg/g had 81% sensitivity and 85% specificity for diagnosis of moderate or severe inflammation. Ordinal regression analysis showed the probability of a greater or lesser degree of inflammation based on the value of preoperative FC. ConclusionsFC is an excellent biomarker of inflammatory activity in small bowel CD as it correlates with histologic inflammation in the surgical specimen.

Fecal calprotectin as a non-invasive biomarker for intestinal involvement of Behçet's disease.

The diagnostic and prognostic values of fecal calprotectin (FC) levels in patients with inflammatory bowel diseases have been proven. However, little is known about the usefulness of FC measurement in predicting intestinal involvement of Behçet's disease (BD). Forty-four consecutive patients with systemic BD who underwent colonoscopy for the evaluation of gastrointestinal symptoms were prospectively enrolled between November 2012 and March 2014 in a single tertiary medical center. Fecal specimens from the patients were obtained the day before bowel cleansing and 3 months after colonoscopy. Twenty-five patients showed intestinal ulcerations on colonoscopy (12 [48.0%] typical and 13 [52.0%] atypical ulcerations). The median FC level in the intestinal BD group was significantly higher than that in the non-diagnostic group (112.53 [6.86-1604.39] vs 31.64 [5.46-347.60] µg/g, respectively, P = 0.003). Moreover, the typical ulceration group showed a significantly higher median FC level than the atypical ulceration group in patients with intestinal BD (435.995 [75.65-1604.39] vs 71.42 [6.86-476.94] µg/g, respectively, P = 0.033). Multivariate analysis revealed higher FC as an independent predictor of intestinal BD (OR = 38.776; 95% CI = 2.306-652.021; P = 0.011). The cut-off level of FC for predicting intestinal BD was 68.89 µg/g (76% sensitivity and 79% specificity). The absolute changes between fecal calprotectin levels and the disease activity index of intestinal BD from initial diagnosis of intestinal BD to 3 months after diagnosis were significantly correlated (Pearson's correlation coefficient = 0.470, P = 0.027). The FC level might serve as a non-invasive surrogate marker of intestinal involvement of BD.

Faecal calprotectin: A reliable diagnostic and prognostic biomarker in inflammatory bowel disease

Faecal calprotectin (FC) is supposed to be a reliable biomarker that quantifies intestinal inflammation in inflammatory bowel disease (IBD). This cross sectional study was aimed to determine the role of FC level in screening of suspected IBD patients and monitoring treatment response. This study was conducted by measurement of FC using a commercially available ELISA kit among 50 patients with chronic diarrhea who underwent colonoscopic evaluation (25 IBD cases, 10 other organic bowel diseases and 15 disease control) and 12 healthy control. IBD patients were followed up after one month of medical treatment. FC level showed significantly higher value (p&lt;0.001) among IBD patients (496.7±127.15?g/g) than those in disease control (82.17±75.64?g/g) and healthy control (27±18.2?g/g). Measurement of FC in diagnosing IBD revealed the sensitivity 100%, specificity 66%, PPV 83% and NPV 100%. The FC level decreased significantly (p&lt;0.001) after one month of medical treatment of IBD patients (90±43?g/g) from pre treatment value (607.56±94?g/g). FC can be used as a reliable biomarker in screening of suspected IBD patients and to monitor treatment response.Bangladesh J Med Microbiol 2014; 08 (01): 12-15

Accuracy of Consecutive Fecal Calprotectin Measurements to Predict Relapse in Inflammatory Bowel Disease Patients

Accuracy of Consecutive Fecal Calprotectin Measurements to Predict Relapse in Inflammatory Bowel Disease Patients

P-227 Impact of Fecal Calprotectin Measurement on Decision-making in Children with Inflammatory Bowel Disease

P-227 Impact of Fecal Calprotectin Measurement on Decision-making in Children with Inflammatory Bowel Disease

P169 Usability of a home-based test for the measurement of fecal calprotectin in IBD patients

Background: Fecal calprotectin (FC) correlates well with mucosal healing and risk of relapse in inflammatory Bowel Disease (IBD). An obstacle for a broader use of FC measurement in routine practice is the need to bring stool samples at the hospital or the send them by mail. The aim of our work was to test the usability of a home-based test for the measurement of FC in IBD patients. Methods: IBD patients in clinical remission or mild disease activity and declaring motivation to perform home-based FC measurements were prospectively recruited in three IBD centres in Oslo, Barcelona and Liège. They received a standardized training. They were instructed to collect and extract stools and to measure FC with a dedicated tool and smartphone application, 5 times at two weeks intervals over a 8 weeks period. The included patients had to fill in a usability questionnaire made of simple questions and Linkert scales at the first and the last FC measurement. Two global scores were calculated integrating the different aspects of usability: the System Usability Scale (SUS: 0–100) and the Global Usability Score (GUS: 0–85). FC was also centrally measured by ELISA. Results: 58 patients were recruited, including 18 ulcerative colitis (UC) and 40 Crohn's disease (CD), 30 females. Median (IQR) age was 35 yrs (27–40), median (IQR) HBI in CD was 0 (0–4), median (IQR) Clinical Mayo in UC was 0 (0–1). Over the 58 included patients, 42 performed at least one FC measurement and 27 performed all the FC requested measurements. The median (IQR) GUS (0–85) at the first and last use were 74 (69–80) and 77 (68–83), respectively; the median (IQR) SUS (0–100) at the first and last use were 85 (78–90) and 81 (70–88), respectively. Adherence to the planned measurements and usability of the tool were higher in females and in less severe disease. The inter-class correlation coefficient between home-based and centrally measured FC was 0.85. Conclusions: Around three quarters of the patients who declared themselves motivated to use home-based test of FC measurement actually did it, but only half of them fully adhered to the planned measurements. Usability scores for the home-based test were high. There was a very good correlation with the centrally measured FC by ELISA.