Posted on behalf of Callum
-----Original Message-----
From: Fraser Callum (NHS TAYSIDE)
Sent: 06 December 2014 09:14
To: OConnor John (ROYAL DEVON AND EXETER NHS FOUNDATION TRUST)
Subject: FOB
Hi John
Good of you to raise the subject of FOB in the ACB Mailbase. Well spotted in that huge NICE document! I read the Mailbase archives but do not participative actively since most of the e-mails are not too interesting or relevant for me, being mostly retired (aye, that'll be right). I would really appreciate it if you could post the following rather long message as a contribution from me on this subject. I think that it really is time to start some serious discussion on the use of FIT (faecal immunochemical tests for haemoglobin) in this setting. FIT are going to come, which gives us a real opportunity to lead rather than follow, in my view. Thanks in advance.
Best regards. Callum
Professor Callum G Fraser
Phone +44 [0] 1382 553799
FAX +44 [0] 1382 425679
FOB - No - FIT - Yes!
The NICE guidelines to which John O'Conner refers are a draft for consultation and not a definitive statement. It is a large document, replete with recommendation on the use of laboratory medicine investigations.
Section 1,3 is on lower gastrointestinal cancers. Section 1.3.6 states:
Offer testing for occult blood in faeces to assess for colorectal cancer in people without rectal bleeding who: have abdominal pain or have weight loss or are aged under 60 and have a change in bowel habit or iron-deficiency anaemia (with haemoglobin levels of 12 g/dl or below for men and 11 g/dl or below for women). [new 2015].
The even larger full guidelines (405 pages) gives the evidence. For FOB, the statement reads: Faecal occult blood (6 studies, N = 9871) conducted in symptomatic patients presenting in a primary care setting is associated with sensitivities that ranged from 0-84%, specificities that ranged from 76-87%, positive predictive values that ranged from 0-16%, and false negativity rates that ranged from 16-100% for colorectal cancer.
These performance characteristics, which do not exactly impress me (or many others) were derived from studies using traditional guaiac-based faecal occult blood tests (gFOBT).with one exception,
The real problem lies in the fact that the document does not take into account that traditional gFOBT are not at all the same as the newer FIT (faecal immunochemical tests for haemoglobin). These are very different tests. I suspect that the marked differences are not widely recognised and both tests are lumped together as FOB. This is wrong and, while use of gFOBT is definitely to be deprecated for a large number of reasons, well documented in the literature and guidelines to date, I strongly suggest that FIT are IT in the context of primary care.
A number of studies have been published over recent time that have examined use of FIT in the assessment of patients with lower abdominal symptoms and I know that there are more "in press". They all show that the Negative Predictive Values for colorectal cancer, high-risk adenoma and inflammatory bowel disease are very high. Thus, FIT provide an excellent rule-out test for significant colorectal disease. In view of the current crisis in colonoscopy, with demand outstripping resource, and the fact that most patients referred for this costly and invasive investigation do not have significant colorectal disease, use of FIT in primary care for those with other than "red flag" symptoms would be an excellent means to direct the scarce resource to those who would really benefit.
Professionals in laboratory medicine could get themselves ahead of the game by investigating use of FIT, especially quantitative FIT that give numerical estimates of faecal haemoglobin concentration, in their own settings and establishing FIT as a routine test. Please don't get pressurised into going back to the obsolete gFOBT. Use a test that is FIT for purpose. I am sure it will come: let's lead rather than follow.
********************************************************************************************************************
This message may contain confidential information. If you are not the intended recipient please inform the
sender that you have received the message in error before deleting it.
Please do not disclose, copy or distribute information in this e-mail or take any action in reliance on its contents:
to do so is strictly prohibited and may be unlawful.
Thank you for your co-operation.
NHSmail is the secure email and directory service available for all NHS staff in England and Scotland
NHSmail is approved for exchanging patient data and other sensitive information with NHSmail and GSi recipients
NHSmail provides an email address for your career in the NHS and can be accessed anywhere
********************************************************************************************************************
------ACB discussion List Information--------
This is an open discussion list for the academic and clinical community working in clinical biochemistry.
Please note, archived messages are public and can be viewed via the internet. Views expressed are those of the individual and they are responsible for all message content.
ACB Web Site
http://www.acb.org.uk
Green Laboratories Work
http://www.laboratorymedicine.nhs.uk
List Archives
http://www.jiscmail.ac.uk/lists/ACB-CLIN-CHEM-GEN.html
List Instructions (How to leave etc.)
http://www.jiscmail.ac.uk/
|
