Scottish Bowel Screening Center Laboratory

King's Lynn, United Kingdom

Scottish Bowel Screening Center Laboratory

King's Lynn, United Kingdom

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Fraser C.G.,Scottish Bowel Screening Center Laboratory | McDonald P.J.,Scottish Bowel Screening Center Laboratory | Colford L.,Scottish Bowel Screening Center Laboratory | Irvine A.,Scottish Bowel Screening Center Laboratory | And 4 more authors.
Journal of Medical Screening | Year: 2010

The format of the traditional guaiac faecal occult blood test (gFOBT), particularly the collection technique, might cause difficulties for some. A multistage evaluation of alternative tests was performed. Firstly, four tests with different faecal collection approaches were assessed: a focus group recommended further investigation of a wipe gFOBT. Secondly, 100 faecal samples were analysed using two wipe tests and the routine gFOBT: no differences were found. Thirdly, a wipe gFOBT was introduced. Over 21 months, 400 requests were made and 311 wipe kit sets were submitted for analysis: 153 (49.2%) were negative, 21 (6.8%) positive (all 3 kits positive), 96 (30.9%) weak positive (1 or 2 positive) and 41 (13.2%) un-testable. Forty-three participants were referred for colonoscopy. Outcome data were provided on 39 participants: nine declined colonoscopy, two were judged unsuitable, two did not attend, two were already in follow-up, 13 had normal colonoscopy and two normal barium enema, two had diverticular disease, two had a metaplastic polyp, four had a low-risk adenoma and one had a high-risk adenoma. No participant had cancer. Detection of significant neoplasia was small. The use of the wipe gFOBT was ceased: it cannot be recommended as a screening test for bowel cancer.


Cheuvront S.N.,U.S. Army | Fraser C.G.,Scottish Bowel Screening Center Laboratory | Kenefick R.W.,U.S. Army | Ely B.R.,U.S. Army | Sawka M.N.,U.S. Army
Clinical Chemistry and Laboratory Medicine | Year: 2011

Background: Dehydration is a common medical problem requiring heuristic evaluation. Our aim was to develop a quantitative and graphical tool based on serial changes in either plasma osmolality (Posm), urine specific gravity (Usg), or body mass (Bm) to aid in determining the probability that a person has become dehydrated. A secondary purpose was to validate use of the tool by dehydrating a group of volunteers. Methods: Basic data were obtained from a recent study of biological variation in common hydration status markers. Four reference change values (RCV) were calculated for each variable (Posm, Usg, Bm) using four statistical probabilities (0.80, 0.90, 0.95, and 0.99). The probability derived from the Z-score for any given change can be calculated from: Z=change/[2 1/2(CVa 2+CVi 2) 1/2]. This calculation was simplified to require one input (measured change) by plotting the RCV against probability to generate both an empirical equation and a dual quantitative-qualitative graphic. Results: Eleven volunteers were dehydrated by moderate levels (-2.1% to-3.5% Bm). Actual probabilities were obtained by substituting measured changes in Posm, Usg, and Bm for X in the exponential equation, Y=1-e -K•X, where each variable has a unique K constant. Median probabilities were 0.98 (Posm), 0.97 (Usg), and 0.97 (Bm), which aligned with 'very likely' to 'virtually certain' qualitative probability categories for dehydration. Conclusions: This investigation provides a simple quantitative and graphical tool that can aid in determining the probability that a person has become dehydrated when serial measures of Posm, Usg, or Bm are made. © 2011 by Walter de Gruyter Berlin Boston.


Petersen P.H.,University of Bergen | Fraser C.G.,Scottish Bowel Screening Center Laboratory
Accreditation and Quality Assurance | Year: 2010

The setting of analytical quality specifications in laboratory medicine has attracted attention for many years. Over time, many strategies were advocated and all had advantages and disadvantages. In the final decade of the last millennium, considerable confusion existed on how to define analytical quality specifications correctly and how to apply them in everyday practice. This led to wide professional interest. In 1999, a consensus conference sponsored by IUPAC, IFCC and WHO was held in Stockholm on "Strategies to Set Global Analytical Quality Specifications in Laboratory Medicine". The consensus set useful and well-documented strategies for the setting of analytical quality specifications into a hierarchy with the best strategy at the highest level, namely, (1) Evaluation of the effect of analytical performance on clinical outcomes in specific clinical situations, (2) Evaluation of the effect of analytical performance on clinical decisions in general, (3) Published professional recommendations, (4) Performance goals set by regulatory bodies and EQAS organisers, and (5) Goals based on the current state of the art. Much success has been achieved since the promulgation of the statement with the approach being adopted by many in laboratory medicine for a very wide variety of purposes, particularly in quality management. However, there is a requirement for additional investigation of, inter alia, quality specifications for examinations done on measurements performed on ordinal and nominal scales, pre-analytical factors and matrix effects, examinations done as POCT, target values of control materials, and ways in which analytical quality specifications can be used both to set what is the optimum performance and as a tool for assessment of everyday practice. © 2010 Springer-Verlag.


Petersen P.H.,University of Bergen | Sandberg S.,University of Bergen | Fraser C.G.,Scottish Bowel Screening Center Laboratory
Clinical Chemistry and Laboratory Medicine | Year: 2011

The Stockholm conference held in 1999 on "Strategies to set global analytical quality specifications (AQS) in laboratory medicine" reached a consensus and advocated the ubiquitous application of a hierarchical structure of approaches to setting AQS. This approach has been widely used over the last decade, although several issues remain unanswered. A number of new suggestions have been recently proposed for setting AQS. One of these recommendations is described by Haeckel and Wosniok in this issue of Clinical Chemistry and Laboratory Medicine. Their concept is to estimate the increase in false-positive results using conventional population-based reference intervals, the delta false-positive rate due to analytical imprecision and bias, and relate the results directly to the current analytical quality attained. Thus, the actual estimates in the laboratory for imprecision and bias are compared to the AQS. These values are classified in a ranking system according to the closeness to the AQS, and this combination is the new idea of the proposal. Other new ideas have been proposed recently. We wait, with great interest, as should others, to see if these newer approaches become widely used and worthy of incorporation into the hierarchy. © 2011 by Walter de Gruyter Berlin New York.


Fraser C.G.,University of Dundee | Digby J.,Scottish Bowel Screening Center | McDonald P.J.,Scottish Bowel Screening Center Laboratory | Strachan J.A.,Scottish Bowel Screening Center Laboratory | And 2 more authors.
Journal of Medical Screening | Year: 2012

Objectives To evaluate a two-tier reflex guaiac-based faecal occult blood test (gFOBT)/faecal immunochemical test (FIT) algorithm in screening for colorectal cancer. Setting Fourth screening round in NHS Tayside (Scotland). Methods gFOBT were sent to 50-74-year-olds. Participants with five or six windows positive were offered colonoscopy. Participants with one to four windows positive were sent a FIT and, if positive, were offered colonoscopy. Participants providing an untestable gFOBT were sent a FIT and, if positive, were offered colonoscopy. Outcomes following positive results, cancer stages and key performance indicators were assessed. Results Of 131,885 invited, 73,315 (55.6%) responded. There were 66,957 (91.3%) negative, 241 (0.3%) strong positive, 5230 (7.1%) weak positive and 887 (1.2%) untestable results. The 241 participants who had five or six windows positive had more cancers than those positive by other routes: only 3 of the 30 cancers (9.7%) were Dukes' A. Among the 983 positive results from the weak positive gFOBT then positive FIT route, there were fewer cancers and more normal colonoscopies, but more adenomas than in the group with a strong positive gFOBT. In those with an untestable gFOBT, 77 had a positive FIT result, with fewer true and more false positive results than in the other groups. Fewer males had cancer and stages were earlier than in females, but more had adenoma. The detection rate for cancer was 0.18% and the PPV for cancer and all adenomas was 41.3%. Conclusions The algorithm and FIT following a weak positive gFOBT have advantages. FIT following an untestable gFOBT warrants review.


Digby J.,University of Dundee | McDonald P.J.,Scottish Bowel Screening Center Laboratory | Strachan J.A.,Scottish Bowel Screening Center Laboratory | Libby G.,University of Dundee | And 2 more authors.
Journal of Medical Screening | Year: 2013

Objectives To investigate the characteristics of participants screened for bowel cancer using a faecal immunochemical test for haemoglobin (FIT). Setting Scottish Bowel Screening Programme. Methods 65909 men and women in two NHS Boards, aged 50 to 74, were invited to participate in an evaluation of FITas a first-line test. Uptake was calculated by sex, age in quintiles, and deprivation in quintiles, and compared with a group who had completed a guaiac faecal occult blood test (gFOBT) and for whom details of sex, age and deprivation were well documented. Results FIT kits from 38672 participants were tested. he overall uptake of 58.7% was significantly higher than the 53.9% for gFOBT (p, 0.0001). Uptakes in the two NHS Boards were 57.6% and 54.4% for men and 63.2% and 59.1% for women, higher than the 49.5% and 58.1% completing gFOBT. Uptake was higher for FIT than gFOBT in all age and deprivation quintiles for both men and women in both NHS Boards. The difference in uptake fell with age for men but rose for women; the increase in uptake was greater for men than women. Uptake fell as deprivation decreased for both sexes, and was similar in both NHS Boards. Conclusions Use of FIT increases uptake over gFOBT, and the greatest increases are seen in men, younger participants, and more deprived individuals, groups for which an increase in uptake is likely to be beneficial. The results support a move to FIT as a first-line screening test for those countries still using gFOBT.


Digby J.,University of Dundee | McDonald P.J.,Scottish Bowel Screening Center Laboratory | Strachan J.A.,Scottish Bowel Screening Center Laboratory | Libby G.,University of Dundee | And 2 more authors.
Journal of Medical Screening | Year: 2014

Objective: To investigate the relationship between deprivation and faecal haemoglobin concentration (f-Hb). Setting: Scottish Bowel Screening Programme. Methods: A total of 66725 men and women, aged 50 to 74, were invited to provide a single sample for a faecal immunochemical test. Deprivation was estimated using the Scottish Index of Multiple Deprivation quintiles: f-Hb was measured (OCSensor, Eiken, Japan) on 38439 participants. The relationship between deprivation quintiles and f-Hb was examined. Results: Median age was 60 years, 53.6% women, with 14.1%, 19.7%, 17.7%, 25.9% and 22.6% in the lowest to the highest deprivation quintiles respectively. No detectable f-Hb was found in 51.9%, ranging from 45.5% in the most deprived up to 56.5% in the least deprived. As deprivation increased, f-Hb increased (p<0.0001). This trend remained controlling for sex and age (p<0.001). Participants in the most deprived quintile were more likely to have a f-Hb above a cut-off of 80 μg Hb/g faeces compared with the least deprived, independent of sex and age (adjusted odds ratio 1.70, 95% confidence interval: 1.37 to 2.11). Conclusions: Deprivation and f-Hb are related. This has important implications for selection of cut-off f-Hb for screening programmes, and supports the inclusion of deprivation in risk-scoring systems. © The Author(s) 2014.


PubMed | Scottish Bowel Screening Center Laboratory
Type: Journal Article | Journal: Journal of medical screening | Year: 2011

The format of the traditional guaiac faecal occult blood test (gFOBT), particularly the collection technique, might cause difficulties for some. A multistage evaluation of alternative tests was performed. Firstly, four tests with different faecal collection approaches were assessed: a focus group recommended further investigation of a wipe gFOBT. Secondly, 100 faecal samples were analysed using two wipe tests and the routine gFOBT: no differences were found. Thirdly, a wipe gFOBT was introduced. Over 21 months, 400 requests were made and 311 wipe kit sets were submitted for analysis: 153 (49.2%) were negative, 21 (6.8%) positive (all 3 kits positive), 96 (30.9%) weak positive (1 or 2 positive) and 41 (13.2%) un-testable. Forty-three participants were referred for colonoscopy. Outcome data were provided on 39 participants: nine declined colonoscopy, two were judged unsuitable, two did not attend, two were already in follow-up, 13 had normal colonoscopy and two normal barium enema, two had diverticular disease, two had a metaplastic polyp, four had a low-risk adenoma and one had a high-risk adenoma. No participant had cancer. Detection of significant neoplasia was small. The use of the wipe gFOBT was ceased: it cannot be recommended as a screening test for bowel cancer.

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