Audit of Faecal Occult Blood requests Clinical Biochemistry North Bristol NHS Trust ACB SW and Wessex Audit Meeting Thursday 17 th November 2011 Kerry.

Audit of Faecal Occult Blood requests Clinical Biochemistry North Bristol NHS Trust

ACB SW and Wessex Audit Meeting

Thursday 17th November 2011

Kerry Grant

Lead Biomedical Scientist, POCT

Background / Guidelines

?Need to continue to offer FOB test within the dept. Introduction of NHS Bowel Cancer Screening Programme Other departments withdrawing the service Questions over the future of YEQAS Occult Blood scheme

Synopsis of current guidance Over 60 yrs of age covered by screening program FOB test NOT recommended in symptomatic patients FOB test should NOT be used for investigation of anaemia Strong recommendations about type and quality of analysis

Especially with regards to collection and storage of samples Decided to look at NBT samples / practice

Screening program (England)

Who is eligible for bowel cancer screening? NHS Bowel Cancer Screening Programme offers screening

every two years to all men and women aged 60 to 69. People over 70 can request a screening kit.

Age extension In December 2007 the Cancer Reform Strategy stated that

the NHS Bowel Cancer Screening Programme would be extending the age range for screening from April 2010 to invite men and women up to their 75th birthday.

By October 2011, 32 of the 58 local screening centres had started inviting the extended population.

Recorded details on all FOB requests in a two week period in January 2011

Following original discussions a change was made immediately to analytical procedure. Samples are no longer stored ‘wet’ prior to analysis but are

applied, ‘spread’, on to the hema-screen test card on the day of receipt or as soon as possible after receipt.

NBT Biochemistry mini-audit

Data collected

Date of sample, date received Origin of sample (GP codes) Date sample ‘spread’ Patient Date of Birth – obtains age Clinical details Number of samples per patient Result

Sample numbers

Audit covered two weeks (10 working days) 4/1/11 – 18/1/11

Total number of samples = 79 (around 39 per week) 36 single samples 2 doubles 13 triples

Total number of patients = 51

Sample origin

77 samples from GP Surgeries 49 patients

From 27 practices (requesters)

2 samples from Hospital departments 2 patients

1 ITU 1 Medical Admissions Ward

Delays in sample prep

Time to dry sample 'spreading'

02468

10121416182022242628

0 2 4 6 8 10 12 14 16 18 20 22 24

Mor

e

Days

Nu

mb

er o

f sa

mp

les

Samples processed on first working day after receipt.

Graph shows time from date of collection to date of processing

Requesting patterns

Patient requests per GP requester

02

4

68

10

1214

1 2 3 4 5 6 7 More

Number of patients

Nu

mb

er o

f G

Ps

Most GPs requested FOB only

once or twice

Number of samples per requester

0

2

4

6

8

10

12

1 2 3 4 5 6 7 8 9 10 More

Number of samples

Nu

mve

r o

f re

qu

este

rs

Most requesters did not arrange for multiple samples

Demographics

Distrubution of patient ages

0

2

4

6

8

10

12

Age

Nu

mb

er

of

pat

ien

ts

Reasons for requests

Out of the 51 patients: 6 had no clinical history 28 had GI / bowel related symptoms

Therefore inappropriate requests 13 had haematological symptoms

Anaemia 4 had ‘other’ histories

1 diabetes review 1 patient concern 1 smelly urine 1 blood in urine

A maximum of 7 (13.7%) may be appropriate

GI symptoms

2 patients previous cancer (1 bowel, 1 lung) 1 had Crohn’s 1 had diverticulitis 1 had weight loss Others

Altered bowel habit Loose stools Altered stool colour Constipation Rectal bleeding

Results

7/79 samples positive 6 patients

Both inpatients (single samples) ITU – pyrexia, diarrhoea F105 – low Hb

2 with low Hb / anaemia 1 with PR bleeding (this was a I yr old) 2 with no clinical details

Use in symptomatic patients?

Request and result demographics

17 patients < 60 yrs of age 1 positive result (the infant) 2 with no Clinical details 4 with haem symptoms 9 with GI / bowel symptoms (incl. prev. bowel Ca) 1 ‘patient concern’

13 patients > 75 yrs of age 1 positive result (anaemia) 5 with haem symptoms 4 with GI / bowel symptoms 3 ‘other’

Thoughts?

Many inappropriate requests Patients with GI symptoms Investigation of anaemia Patients within screening age group

Delay in follow-up of patients with symptoms? Failure to follow-up if FOB test negative?

Inappropriate samples (not dried at source) If we keep test do we change method?

Bowel Cancer Campaigns

Focus on Bowel Cancer Symptoms and Early Detection

April 2011 was Bowel Cancer Awareness Month (BCAM), men and women across the UK were

encouraged to be aware of the signs and symptoms of bowel cancer and to act on their

concerns, sooner rather than later.

Bowel Cancer UK are busy planning for BCAM 2012!

31st January 2011

Government launches first ever cancer awareness campaign – Be Clear on Cancer.

Campaign piloted for seven weeks in two areas, the east of England and the South West! Television and radio advertisements featured “real GPs encouraging patients to talk to them about changes in their poo”.

Talk about your poo!

How many?

FOB samples received

050

100150200250300350400

Oct

-10

Nov

-10

Dec

-10

Jan-

11

Feb

-11

Mar

-11

Apr

-11

May

-11

Jun-

11

Jul-1

1

Aug

-11

Sep

-11

Oct

-11

Month

Nu

mb

er

Talk about your poo!

To continue or not…..

Plenty of evidence to suggest not:

NICE Guidelines for Referral for suspected Cancer (CG271, sections on upper and low gastrointestinal cancer) states:

In patients for whom the decision to refer has been made, no examinations or investigations other than those referred to earlier (abdominal and rectal examination, full blood count) are recommended as this may delay referral.

Scottish Intercollegiate Guideline Network 67 states:

Although faecal occult blood testing (FOBT) is an effective means of population screening, it is too sensitive to be used in guiding investigation of symptomatic patients.

British Society of Gastroenterology Guidelines for the Management of Iron Deficiency Anaemia states:

FOB testing is of no benefit in the investigation of Iron Deficiency Anaemia.

FOB testing - Chemical v Immunologic

● Chemical testing - Inexpensive & easyDisadvantages:

Dietary restriction – substances in fruit & vegetables can mimic haem and cause chemical FOB tests to be falsely positive.

Not specific for blood from lower GI bleed – as haem can travel intact from the stomach or small intestine and into the stool – red meat should be restricted as this can cause false positive results.

Positive result if there is bleeding anywhere in the stomach or intestines

hema-screen

Intended to be used by professionals as an aid in the diagnosis of asymptomatic gastrointestinal conditions.

Recommended for use in routine hospital testing & mass screening programs.

Analytical detection limit of 0.6mg Hb/gm of faeces. Cost

£59.59 per 100 test kit (EROS price) Assuming three slides per patient = £1.79 per patient

hema-screen

Currently samples sent to lab in universal containers and applied

to hema-screen test slides.

But evidence from studies shows: Potential interference from plant peroxidases can be eliminated

by drying the faeces on the FOBT for 48 hours before analysis. Bacterial degradation of the pseudo-peroxidase activity of haem

in moist faeces is significant, and can be slowed by collecting faeces directly onto the guaiac paper and allowed to dry.

If collected on test slide, stool sample stable for up to 21 days

hema-screen triple slide

hema-screen also available as a triple slide patient pack (similar to that used by NHS Bowel Cancer Screening Programme).

Kit components Triple patient slides, developing solution, applicator sticks,

patient instructions and foil-lined mailing pouches Analysis

Patient collects samples from three consecutive bowel movements directly on to the test slides before returning to lab.

Slide development stage performed in lab Cost

£85.64 per 50 test kit (Alpha Labs List Price) Assuming three slide kit per patient = £1.71 per patient

Method Immunochemical

Kit Components Everything required to perform 20 tests

Analysis Sampler given to patient. Using the spiral sampler from the collection

tube, patient collects sample from 3 different sites of same faecal sample and reinserts into collection device. Procedure repeated on three consecutive days (using same sampler) before returning to lab.(Extracted faecal sample should be stored chilled between sampling and up to 8 days.)

Test strip dipped into collection bottle and results of test read 10 minutes after addition of the strip to the collection bottle. Strip contains built-in procedural control.

Quadractech Check4Haemoglobin Test

Detection Limit 0.4 mg Hb/g of faeces

Interfering substances: Specific for haemoglobin

Samples shouldn’t be collected while patient has bleeding haemorrhoids, constipation, during or immediately after menstruation

No dietary restriction necessary Cost

£23.65 per 20 test kit £1.18 per patient

Quadractech Check4Haemoglobin Test

Immunostics hema-screen - CONFIRM

Method Chemical & Immunochemical

Kit Components 25 tests – envelopes, buffer tubes & cassettes

Analysis Patient collects samples from three consecutive bowel

movements directly on to the test slides before returning to lab.Stability after sample application is 21 days for gauaic test and 30 days for immunochemical.

Slide Development: As before Positive test results can then be further tested specifically

for human haemoglobin using the same faecal sample. Buffer extraction & application to test cassette.

Best of both Cost

£73.28 per 25 test kit – Triple slide format includes 5 immunochemistry confirmatory tests which can be purchased separately to match testing requirements.

(Alpha Labs List Price) £2.92 per patient

Immunostics hema-screen - CONFIRM

Or we could buy a dog!

Chemical compounds specific to some cancers are thought to be contained in breath & stools, which dogs can detect with a high degree of accuracy.

Scientists in Japan used a Labrador to carry out 74 sniff tests on samples obtained from 48 people with bowel cancer and 258 healthy volunteers.

The dog’s ability to detect cancer from breath was 95% accurate overall and 98% accurate from stools.

Reported that accuracy was even higher for early cancer!