Diagnosing colorectal cancer and inflammatory bowel disease in primary care: The usefulness of tests for faecal haemoglobin, faecal calprotectin, anaemia and iron deficiency. A prospective study.
OBJECTIVE
Abdominal complaints are common reasons to consult primary care but they are seldom caused by colorectal cancer (CRC), high-risk adenomas (HRAs), or inflammatory bowel disease (IBD). Reliable diagnostic aids would be helpful in deciding which patients to refer for bowel imaging. Our aim was to assess the value of a faecal immunochemical test (FIT) and a faecal calprotectin (FC) test in detecting CRC, HRAs and IBD in primary care, and the value of combining these tests with anaemia and iron-deficiency tests.


METHODS
This prospective study included 373 consecutive patients that received a FIT or a FC test ordered by a primary care physician. We collected samples for FITs, FC tests, full blood counts and iron-deficiency tests. Physicians were instructed to refer patients with a positive FIT or FC test (cut-off ≥100μg/g) for bowel imaging. The patients' presenting symptoms were recorded. Patients were followed for 2 years.


RESULTS
The best test for detecting CRC and IBD was the combination of the FIT and haemoglobin concentration. This test had a sensitivity, specificity, positive predictive value and negative predictive value of 100%, 61.7%, 11.7% and 100%, respectively. The FIT detected a significantly larger proportion of CRC, HRAs and IBD than the FC test (0.92 versus 0.46, 95% confidence interval 0.22-0.67).


CONCLUSIONS
A negative FIT combined with a normal haemoglobin concentration could rule out CRC and IBD with a high degree of safety. This could be useful in prioritising referrals for bowel imaging from primary care.
a Department of Public Health and Clinical Medicine, Unit of Research, Education, and Development, Östersund Hospital , Umeå University , Östersund , Sweden.
Cecilia
C
Högberg
b Department of Public Health and Clinical Medicine, Division of Medicine , Umeå University , Umeå , Sweden.
Pontus
P
Karling
c Department of Surgical and Perioperative Sciences , Umeå University , Umeå , Sweden.
Jörgen
J
Rutegård
a Department of Public Health and Clinical Medicine, Unit of Research, Education, and Development, Östersund Hospital , Umeå University , Östersund , Sweden.
Mikael
M
Lilja
D000236:Adenoma / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D018798:Anemia, Iron-Deficiency / Q000175:diagnosis*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D005243:Feces / Q000737:chemistry; D005260:Female; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000175:diagnosis*; D007501:Iron / Q000097:blood; D039841:Leukocyte L1 Antigen Complex / Q000032:analysis; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D009780:Occult Blood; D011320:Primary Health Care; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013548:Sweden
D006454:Hemoglobins; D039841:Leukocyte L1 Antigen Complex; D007501:Iron
Anaemia; colorectal cancer; faecal calprotectin; faecal immunochemical test; inflammatory bowel disease; occult blood; primary care