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PubMed2005

Clinical performance of a self-etching adhesive at 18 months.

PURPOSE: To test the null hypothesis that beveling and/or etching enamel would not affect the 18-month clinical performance of the self-etching adhesive Clearfil SE Bond (CSEB) in noncarious cervical lesions (NCCL). METHODS: With Institutional Review Board approval, 34 patients were enrolled in this study. A total of 120 NCCL was selected and assigned to four groups: (1) CSEB was applied without any cavity preparation; (2) CSEB was applied after beveling enamel; (3) CSEB was applied after etching enamel for 15 seconds with 35% phosphoric acid; (4) CSEB was applied after beveling and etching enamel. A microfilled composite resin was used for all restorations. RESULTS: At 6 months after initial placement, 120 restorations (a 100% recall rate) were evaluated. At 18 months, 87 restorations (a 72.5% recall rate) were available for evaluation. A survival rate of 100% was measured for all groups at both 6 and 18 months. Sensitivity to air decreased significantly only for Group 3 (no bevel+acid etch) from baseline to 18 months without statistical changes from 6 months to 18 months. None of the other parameters resulted in significant differences for any of the four groups. However, when data were pooled, both the overall marginal discoloration and the overall marginal adaptation were significantly worse at 18 months than at baseline, while sensitivity to air decreased significantly from baseline to 18 months. The 18-month survival rate of the self-etching adhesive Clearfil SE Bond was not improved by enamel bevel or by enamel etching. Both overall marginal adaptation and overall marginal discoloration were worse at 18 months than at baseline. .

Acid Etching, Dental↗

PubMed2003

Integrating self-referral for mammography into organised screening: results from an Italian experience.

OBJECTIVE: To compare self-referred screenees with respondents to invitation for main performance indicators of mammography screening. SETTING: First round of an organised, population-based screening programme in six districts of northern Italy. METHODS: The screening test was a two-view mammography. Eligible women aged 50-69 years were invited. Self-referred attendees were accepted if they were eligible for screening and had not yet been invited or had been invited >6 months before presentation. Age-specific performance indicators were compared with the calculation of their ratio and 95% confidence intervals (CIs). Total ratios were age standardised. In situ carcinomas were excluded. RESULTS: The eligible population was 183 542 women. There were 112 188 respondents to invitation and 20 280 self-referred attendees. Self-referral rate was inversely related to age. Performance indicators were as follows: recall rate, 5.6% for self-referred attendees vs 5.5% for respondents (ratio 1.02, 95% CI 0.96 to 1.08); total aspiration cytology rate, 37.3% vs 28.3% (1.37, 1.24 to 1.51); biopsy rate, 17.0 vs 12.6 x 1000 (1.51, 1.35 to 1.67); total detection rate, 10.7 vs 7.5 x 1000 (1.70, 1.48 to 1.94); detection rate of pT1 carcinoma, 7.0 vs 6.1 x 1000 (1.35, 1.14 to 1.59); detection rate of pT2-4 carcinoma, 3.5 vs 1.2 x 1000 (3.51, 2.75 to 4.43); false-positive rate, 4.5% vs 4.7% (0.93, 0.87 to 0.99); positive predictive value (PPV) of mammography, 19.1% vs 13.5% (1.59, 1.39 to 1.82); PPV of biopsy, 63.7% vs 60.6% (1.13, 0.98 to 1.29); detected:expected ratio, 5.02 vs 3.37 (1.49, 1.28 to 1.74). All differences were more pronounced among or restricted to women aged 50-54 years. CONCLUSIONS: Self-referred screenees were similar to respondents to invitation in main indicators of screening feasibility such as recall rate and PPV of biopsy, while showing important increases in detection rates and detected:expected ratios, especially among women aged 50-54 years.

Aged↗

PubMed2000

Does the peak-end phenomenon observed in laboratory pain studies apply to real-world pain in rheumatoid arthritics?

Laboratory studies and investigations of patients undergoing painful procedures have compared recalled pain to an average of multiple momentary reports taken throughout the painful experience. This work has shown that recalled ratings of pain are more closely associated with a combination of peak pain and pain proximal to the recall ratings than an average of all momentary reports. However, these studies have examined recalled pain over relatively short periods, usually under 1 hour. In this study of 32 patients with rheumatoid arthritis, momentary pain ratings taken over a 7-day period were compared with pain recalled on the eighth day. Analyses confirmed that a combination of peak and recent pain was a better predictor of recalled patient pain than was a simple average of all momentary pain reports. These results extend our understanding of how individuals remember pain and suggest alternative methods for assessing recalled pain.

Journal Article↗

PubMed1992

Update of the Swedish two-county program of mammographic screening for breast cancer.

The results of the Swedish two-county trial of mammographic screening for breast cancer are presented, updated to December 31, 1990, which is an average of 10.8 years follow-up per person. The main result of the trial in terms of breast cancer mortality remained the same: compared with the control group, the group invited to screening had a relative breast cancer mortality of 0.70 (P = 0.0002) with 95% confidence interval (0.58, 0.85). Analysis of survival showed that relative to the control group, the cancers detected at prevalence screen, incidence screens, and in the interval between screens had a good prognosis, whereas cancers detected in those who had refused screening had a very poor prognosis. When adjusted for tumor size, lymph node status, and tumor grade (differentiation), the better survival associated with incidence screen and interval detection was largely accounted for, indicating that the benefit of incidence screening is largely achieved through the effect of screening on the three prognostic variables, notably size of the tumor. Results indicate that to achieve a substantial mortality reduction, 50% of screen-detected invasive cancers should be less than 15 mm in diameter, at least 30% of screen-detected grade 3 tumors should be less than 15 mm, and at least 70% of screen-detected tumors should not have lymph node metastases. The percentage of grade 3 tumors of a given size should be the same in screen-detected cancers as in clinically detected, and breast cancer prevalence at first screen should be at least three times the expected incidence rate in the absence of screening. This should be achieved without the recall rate for further examination exceeding 9%, and procedures including further imaging techniques and fine needle aspiration or core biopsy should be used before resorting to surgical biopsy. These aims can be achieved in specialist screening centers if particular attention is paid to resources for screening and diagnostic evaluation, specialist training of clinical and technologic screening staff, and ongoing monitoring of mammographic quality, recall rates, and the attributes of the tumors detected.

Adult↗

PubMed1995

Measurement of the costs in two mammographic screening programmes in the province of Florence, Italy.

OBJECTIVES: To estimate and to compare the cost per woman examined and per breast cancer detected in two mammographic screening programmes in the province of Florence. SETTING: Two ongoing, population based, mammographic screening programmes in the province of Florence. The first (district project) was started in the seventies in a rural area, whereas the second (city project) was started in the city at the end of 1990. METHODS: All relevant resources consumed by the programmes (costs) were listed and measured. The costs are related to 1993. The unit cost for each phase (recruitment, screening, assessment) of the screening process was estimated by dividing the total cost of the phase by the number of women examined. The cost per cancer detected was obtained by dividing the total cost of the programme by the number of cancers detected at screening. RESULTS: The costs per woman examined were $38.1 and $41.1 in the district and city programmes respectively. The cost per breast cancer detected was $7424 in the district programme and $5180 in the city programme. Staff accounted for more than 50% of the total cost. The unit cost in the screening phase was higher in the district programme, whereas it was lower in the assessment phase. CONCLUSIONS: Our results are consistent with, although slightly lower than, published estimates of the cost per woman screened. Important parameters for determining the efficiency of a mammographic screening programme are the compliance rate and the recall rate.

Breast Neoplasms↗

PubMed1995

Health education campaign on population control: lessons from Iran.

A descriptive study was carried out in Tehran, the capital of Iran, to investigate a health education campaign on population control. A sample of 68 adults aged 20 to 40 years participated in the study. Each respondent was shown a picture of the campaign. They then filled in a short questionnaire. The main objectives of the study were to measure recall rates and to assess attitude of the subjects. The study results show that recall rates were high (78%), 68% of respondents claimed that the campaign is likely to change their attitudes towards population control, and 87% of participants perceived the main idea of the campaign correctly. The study findings show that there are some significant associations between demographic variables (marital status, having child or not) and perception of the campaign. These may lead health educators and health promoters to communicate more effectively and efficiently in the context of family planning. In countries with a large number of young people, health education campaigns on population control with respect to social values of each society and moral considerations are recommended.

Adult↗

PubMed2004

Predicting one's own forgetting: the role of experience-based and theory-based processes.

The authors examined the hypothesis that judgments of learning (JOL), if governed by processing fluency during encoding, should be insensitive to the anticipated retention interval. Indeed, neither item-by-item nor aggregate JOLs exhibited "forgetting" unless participants were asked to estimate recall rates for several different retention intervals, in which case their estimates mimicked closely actual recall rates. These results and others reported suggest that participants can access their knowledge about forgetting but only when theory-based predictions are made, and then only when the notion of forgetting is accentuated either by manipulating retention interval within individuals or by framing recall predictions in terms of forgetting rather than remembering. The authors interpret their findings in terms of the distinction between experience-based and theory-based JOLs.

Humans↗

PubMed2006

Performance of opportunistic breast cancer screening in Slovenia.

The purpose of the study was to assess performance indicators of opportunistic breast screening carried out in one of the Primary Breast Diseases Centers (PBDC) and to find out if these indicators meet the standards set in "European guidelines for quality assurance in mammographic screening". The records of 1,896 asymptomatic women, aged between 50 and 69 years who attended PBDC for the first time in the period from October 15 1998 to October 15 2002, were reviewed. In all of them, clinical examination and mammography was done. If necessary, non-invasive additional imaging was also performed in the PBDC. If malignancy could not be excluded, the women were referred to the Institute of Oncology (IO) for additional invasive diagnostic procedures. The data on these findings were collected from the records of the IO. We compared our results with the recommended values of performance indicators valid for organized screening programs as determined by "European guidelines". Of 1,896 women, 415 (22%) were recalled for additional imaging. In 335/415 women the suspicion for malignancy was excluded with noninvasive diagnostic methods. Invasive diagnostic procedures were applied in 80/415 women. Carcinomas were detected in 23 women, the majority of them (96%) were non palpable. All carcinomas were ductal; 9 (39%), 7 (30.5%), 7 (30.5%) were grade 1, 2 and 3, respectively. One carcinoma was preinvasive; 20 had the tumor size T1, 1 had T2, while in one the size was not specified. The axillary lymph nodes were negative in 14/23 (61%) women with invasive carcinoma and positive in 5/23 (22%). Surgery of the axilla was considered unnecessary in 4/23 (17%). Diagnostic sensitivity in presented cohort was 96%, specificity 79%. After a negative mammogram 1 interval cancer was detected. Compared to the "European guidelines" we achieved satisfactory results in the number and size of detected and interval cancers, but the analysis showed a higher recall rate with too many false-positive results. Efforts should target lowering the recall rate without reducing the cancer detection rate. Compared to Slovenian average, a large percentage of localized breast cancers in our study claim for organized breast cancer screening program in Slovenia at earliest convenience.

Aged↗

PubMed1995

Searching for information on chemical substances in selected biomedical bibliographic databases.

A method was developed which allows effective searching for information on chemical substances in databases. Several searches for chemicals in bibliographic databases were carried out to analyse the method of indexing chemical names. The recall rates of documents were compared to evaluate information resources as well as searching strategies. Recall rates of documents searched with the CAS Nos. were compared to those searched with substance name. It turned out that searching for substances is most specific and fastest with CAS Nos. They should always be used whenever possible. However, this is not sufficient in many BDs, making an additional search using chemical names necessary. Specific search options that have to be considered for each database are reported.

Abstracting and Indexing↗

PubMed2004

Sensitivity of noncommercial computer-aided detection system for mammographic breast cancer detection: pilot clinical trial.

PURPOSE: To evaluate a noncommercial computer-aided detection (CAD) program for breast cancer detection with screening mammography. MATERIALS AND METHODS: A CAD program was developed for mammographic breast cancer detection. The program was applied to 2,389 patients' screening mammograms at two geographically remote academic institutions (institutions A and B). Thirteen radiologists who specialized in breast imaging participated in this pilot study. For each case, the individual radiologist performed a prospective Breast Imaging Reporting and Data System (BI-RADS) assessment after viewing of the screening mammogram. Subsequently, the radiologist was shown CAD results and rendered a second BI-RADS assessment by using knowledge of both mammographic appearance and CAD results. Outcome analysis of results of examination in patients recalled for a repeat examination, of biopsy, and of 1-year follow-up examination was recorded. Correct detection with CAD included a computer-generated mark indicating a possible malignancy on craniocaudal or mediolateral oblique views or both. RESULTS: Eleven (0.46%) of 2,389 patients had mammographically detected nonpalpable breast cancers. Ten (91%) of 11 (95% CI: 74%, 100%) cancers were correctly identified with CAD. Radiologist sensitivity without CAD was 91% (10 of 11; 95% CI: 74%, 100%). In 1,077 patients, follow-up findings were documented at 1 year. Five (0.46%) patients developed cancers, which were found on subsequent screening mammograms. The area where the cancers developed in two (40%) of these five patients was marked (true-positive finding) by the computer in the preceding year. Because of CAD results, a 9.7% increase in recall rate from 14.4% (344 of 2,389) to 15.8% (378 of 2,389) occurred. Radiologists' recall rate of study patients prior to use of CAD was 31% higher than the average rate for nonstudy cases (10.3%) during the same time period at institution A. CONCLUSION: Performance of the CAD program had a very high sensitivity of 91% (95% CI: 74%, 100%).

Adult↗

PubMedDate not supplied

[Assessment of diagnostic accuracy of mammography carried out for secondary prevention. Results of a test with a sample caseload conducted by 75 Italian radiologists].

PURPOSE: To report the results of a test performed by 75 volunteer radiologists involved in screening program in Italy. MATERIAL AND METHODS: The test includes 12 screening detected cancers and 6 cancers (4 screening detected and 2 interval lesions) with minimal signs at review of a previous negative mammogram. Data on previous experience in mammography (years of activity, years of screening activity, total number of mammograms read and number of mammograms read per year) were also collected. RESULTS: Standards for passing the test were at least 83.3% for sensitivity for screening detected cancers and at most 30% for recall rate among negative cases. Mean sensitivity was 83.9% (median 83.3%, range 50-100%) and mean recall rate was 16.3 (median 14.4%, range 3.8-42.4%). In all, 44 radiologists (58.7%) passed the test. On average 1.4 of 6 cancers with minimal signs were correctly identified. According to readers' experience (at least 5 years in mammographic activity, at least 3 years in screening mammography, at least 10,000 total mammograms read, at least 5,000 per year) radiologists were classified as expert (13) or not (62): no difference in test performance was observed between the two groups. The only significant association occurred for years of mammographic activity and sensitivity. DISCUSSION AND CONCLUSIONS: Test results suggest the need for proper training of radiologists prior to involvement in a screening program. Seeding proficiency tests with cancers with minimal signs was of no benefit as far as evaluation is concerned.

Aged↗

PubMed1998

EEG activity and heart rate during recall of emotional events in hypnosis: relationships with hypnotizability and suggestibility.

The purpose of the present research was to find physiological and cognitive correlates of hypnosis, imaginative suggestibility and emotional experiences. After the administration of a standard hypnotic induction, the EEG and heart rate (HR) were recorded during self-generated happy and sad emotions using a relaxation condition as a control. Physiological recordings were also obtained during three eyes-open and eyes-closed baseline periods: (1) waking rest; (2) early-rest in hypnosis (just after the hypnotic induction); (3) late-rest hypnosis (at the end of hypnotic condition). EEG was recorded at frontal (F3, F4), central (C3, C4), and posterior sites (middle of O1-P3-T5 and O2-P4-T6 triangles). Using log transform of mean spectral amplitude, eight EEG frequency bands (4-44 Hz) were evaluated. High hypnotizable subjects, as compared to the lows, produced a higher theta1 amplitude (4-6 Hz) across both left- and right-frontal and right-posterior areas. These subjects also produced smaller alpha1 amplitude (8.25-10 Hz) over both left and right frontal recording sites. High suggestible subjects, during resting conditions, disclosed higher theta2 (6.25-8 Hz) and alpha1 amplitudes in eyes-closed as compared to an eyes-open condition than did low suggestible subjects. High suggestible subjects also showed, in hypnosis-rest condition, higher 40-Hz amplitudes (36-44 Hz) and HR activity than did low suggestible subjects. Hypnotizability and not suggestibility was found to moderate emotional processing: high hypnotizable individuals self-reported greater levels of emotional experiences than did low hypnotizables especially in terms of negative emotion. High hypnotizables, during processing of emotional material, also disclosed opposite 40-Hz hemispheric asymmetries over anterior and posterior regions of the scalp. These subjects during happiness showed an increased production of 40-Hz activity in the left frontal and central regions of the scalp, while during sadness they showed an increased activity in the right central and posterior regions. The hemispheric asymmetries for relaxation condition were similar, but less marked, to those obtained for happiness. No significant interactions involving both hypnotizability and imaginative suggestibility were found for physiological variables considered in this study. This demonstrates that hypnotizability and suggestibility reflect different underlying psychophysiological activities.

Adult↗

PubMed2004

Enhancing performance of protein and gene name recognizers with filtering and integration strategies.

Named entity (NE) recognition is a fundamental task in biological relationship mining. This paper considers protein/gene collocates extracted from biological corpora as restrictions to enhance the precision rate of protein/gene name recognition. In addition, we integrate the results of multiple NE recognizers to improve the recall rates. Yapex and KeX, and ABGene and Idgene are taken as examples of protein and gene name recognizers, respectively. The precision of Yapex increases from 70.90 to 85.84% at the low expense of the recall rate (i.e., it only decreases 2.44%) when collocates are incorporated. When both filtering and integration strategies are employed together, the Yapex-based integration with KeX shows good performance, i.e., the F-score increases by 7.83% compared to the pure Yapex method. The results of gene recognition show the same tendency. The ABGene-based integration with Idgene shows a 10.18% F-score increase compared to the pure ABGene method. These successful methodologies can be easily extended to other name finders in biological documents.

Abstracting and Indexing↗

PubMed2003

Newborn screening in Indonesia.

In Indonesia, newborn screening is not yet a policy, and the incidence of preventable causes of mental retardation detected by newborn screening is not known. Congenital hypothyroidism (CH) is not infrequent. Without a screening program, unrecognized CH patients were neglected for years. Since May 1999, the International Atomic Energy Agency (IAEA) has assisted in starting a CH Newborn Screening Project to estimate the local incidence of CH and to evaluate the problems associated with the screening. In June 2000, a pilot study was conducted using primary TSH measurement, supplemented by T4 in infants with elevated TSH. The target was to screen 12,000 newborn infants, using cord blood serum taken at birth, or a heel prick between 2 to 6 days of age. Between June 2000 and February 2001, 3,534 neonates born in 4 hospitals were screened using cord blood serum taken at birth (recall rate 3.3%). From March 2001 onwards, the heel prick method was used and participating hospitals increased from 4 to 7. Using this approach, until August 2001, 3,309 samples were analysed and the recall rate was much lower (0.64%). The number of unsatisfactory samples was relatively high due to an unstable process of blood collection. Parental refusal and low acceptance of screening among policy makers resulted from lack of awareness of the dangers of CH, and the screening program was not considered a health priority. Recall of patients after screening was a major barrier, with problems in tracking patients arising from urbanization and a high rate of relocation. To advance the CH screening program nationwide, infrastructure must be improved along with the recall system, and education as well as information campaigns for parents and medical professionals must be intensified. The Department of Health must be persuaded to give a national mandate.

Attitude to Health↗

PubMed2006

Reverse fingerprinting, similarity searching by group fusion and fingerprint bit importance.

Recent research has shown that using data fusion rules in fingerprint-based similarity searching can improve results over traditional searches. Group fusion scores, which use multiple reference compounds, have in particular been shown to be quite effective in increasing enrichment rates over single reference structure based searches. In this paper, the effectiveness of using data fusion with multiple reference compounds to increase similarity search recall rates was investigated using 44 biological targets and four different 2D fingerprinting systems, including a new 2D typed triangle fingerprinting system introduced here. Scaffold-hopping abilities using data fusion rules were investigated using eight (8) different classes of scaffolds active against cGMP phosphodiesterase isoform 5 (PDE5). An approach to using the reference group for ranking and visualizing important fingerprints bits, or reverse fingerprinting, was presented, and used to score and visualize important pharmacophore features within sample active molecules. Finally, similarity statistics within the reference groups were investigated and compared to recall rates.

3',5'-Cyclic-GMP Phosphodiesterases↗

PubMed2003

Comparison of standard and double reading and computer-aided detection (CAD) of interval cancers at prior negative screening mammograms: blind review.

The study evaluates the role of computer-aided detection (CAD) in improving the detection of interval cancers as compared to conventional single (CONV) or double reading (DOUBLE). With this purpose, a set of 89 negative cases was seeded with 31 mammograms reported as negative and developing interval cancer in the following 2-year interval (false negative (FN)=11, minimal signs (MS)=20). A total of radiologists read the set with CONV and then with CAD. Overall, there were 589 cancer and 1691 noncancer readings with both CONV and CAD. Double reading was simulated by combining conventional readings in all 171 possible combinations of 19 radiologists, resulting in a total of 5301 cancer and 15 219 noncancer readings. Conventional single, DOUBLE and CAD readings were compared in terms of sensitivity and recall rate. Considering all 19 readings, cancer was identified in 190 or 248 of 589 readings (32.2 vs 42.1%, chi(2)=11.80, df=1, P<0.01) and recalls were 287 or 405 of 1691 readings (16.9 vs 23.9%, chi(2)=24.87, df=1, P<0.01) at CONV or CAD, respectively. When considering FN and MS cases separately, sensitivity at CONV or CAD was 50.2 or 62.6% (chi(2)=6.98, df=1, P=0.01) for FN and 22.3 or 30.7% (chi(2)=6.47, df=1, P=0.01) for MS cases, respectively. Computer-aided detection (average of 19 readings) was slightly and not significantly less sensitive (sensitivity: 42.1 vs 46.1%, chi(2)=3.24, df=1, P=0.07) but more specific (recall rate 23.9 vs 26.1%, chi(2)=3.8, df=1, P=0.04) as compared to DOUBLE (average of 171 readings). Average sensitivity for FN cases only was 62.6% for CAD and 64.8% for DOUBLE (chi(2)=0.32, df=1, P=0.58). Corresponding values for MS cases were 30.7% for CAD and 35.7% for DOUBLE (chi(2)=3.53, df=1, P=0.06). Compared to CONV, CAD allowed for improved sensitivity, though with reduced specificity, both effects being statistically significant. Computer-aided detection was almost as sensitive as DOUBLE but significantly more specific. Computer-aided detection might be used in the current practice to improve sensitivity of conventional single reading. Based on estimates of screening sensitivity and FN/MS interval cancer expected frequency, the absolute increase of screening sensitivity expected by introducing CAD-assisted reading may be estimated around 0.9%. The use of CAD as a possible surrogate to conventional DOUBLE needs to be confirmed by further studies, which should include a cost-effective analysis.

Breast Neoplasms↗

PubMed2005

Two-tiered immunoreactive trypsinogen-based newborn screening for cystic fibrosis in Colorado: screening efficacy and diagnostic outcomes.

OBJECTIVE: To examine immunoreactive trypsinogen (IRT)-based screening for cystic fibrosis (CF) for recall rate, genotype distribution, and "borderline" sweat test results. STUDY DESIGN: CF newborn screening in Colorado began in 1982, and >1,153,000 infants were screened through 2002 with an IRT-based screen (IRT/IRT). RESULTS: We have identified 313 infants with CF, giving an overall incidence of 1 in 3684 and a Hispanic incidence of 1 in 6495. Fifty-five infants with meconium ileus (17.6%) were excluded from analysis. Fourteen infants with false-negative results were identified (5.4%). The average recall rate was 0.6%, with a positive predictive value of 4.7%. Ninety-three percent of the infants had at least 1 DeltaF508 mutation, and 98% of the infants had at least 1 mutation from the American College of Medical Genetics recommended panel. Six infants had hypertrypsinogenemia and borderline results on sweat tests (30-60 mmol/L). Increased variability in sweat chloride levels were seen in these infants compared with infants with homozygous DeltaF508. Three children with initial borderline results on sweat tests had CF diagnosed. CONCLUSIONS: The recall and false-negative rates of our IRT/IRT CF screening program are reported. Additionally, genotypes of the patients identified mirror the CF population genotypes, reflecting similar disease severity in the screened population. Finally, infants with persistent hypertrypsinogenemia and borderline sweat test results need long-term follow-up.

Chlorides↗

PubMed2002

Basic variables at different positivity thresholds of a quantitative immunochemical test for faecal occult blood.

OBJECTIVES: Screening by faecal occult blood testing (FOBT) is effective in decreasing mortality and incidence of colorectal cancer (CRC). Immunochemical tests have proved to be more cost effective than guaiac FOBTs. The latex agglutination test (LAT) has the advantage of being a fully automated, quantitative test. The aim of this study is to interpret the overall experience with LAT according to different positivity thresholds. SETTING: A population based screening programme is currently running involving subjects aged 50-70, invited every 2 years to have an FOBT. LAT is the standard screening test and has a positivity threshold for further diagnostic tests of 100 ng haemoglobin/ml of sample solution. METHODS: Positivity rates, detection rates for CRC high risk adenomas, and positive predictive values for CRC, high risk adenomas, and low risk adenomas were calculated for several positivity thresholds. RESULTS: 19,132 attendances at screening were recorded (11,774 at first screening, 7358 at subsequent screenings). Progressively increasing the positivity threshold from 100 to 200 ng/ml showed (a) a decrease in positivity rate; (b) a decrease in detection rates for CRC or high risk adenomas; (c) an increase in positive predictive values for cancer; (d) an increase in positive predictive value for high risk adenomas. CONCLUSIONS: Increasing the positivity threshold of the LAT reduces recall rate and improves positive predictive value for cancer or high risk adenomas but substantially decreases the detection rate of CRC and high risk adenomas. For this reason increasing the positivity cut off for LATs is not advisable. On the other hand decreasing the positivity threshold would increase recall rate and sensitivity of screening. Careful evaluation of sensitivity of the quantitative results of the LAT for interval cancers is needed to definitively assess the optimal positivity threshold for LATs in population based screening programmes.

Adenoma↗