Early detection of colon cancer

Hemogram, CA19.9, SOH (fecal occult blood)

The samples are blood and feces; you must fast for blood extraction and not eat red meat, raw fruits or vegetables the 2 days before the stool. No appointment is necessary for the blood collection; the extractions are done from 8:00h – 10:30h from Monday to Friday.

The stool must be delivered in a sterile container purchased at the pharmacy. The patient must not take oily laxatives, barium, magnesium or bismuth salts, at least 72 hours before the sample is taken.

For the sampling you can be guided by the following scheme:










  1. Sit upside down to deposit the sample in the toilet.
  2. Unscrew the sample cup.
  3. Suck in some sample.
  4. Deliver the sample as soon as possible. If it cannot be delivered immediately, keep it at 2-8ºC, 5 days maximum.


The results are delivered after 24-48 hours.

Colon or colorectal cancer is one of the most common cancers in Spain, both in men and women. It usually develops from a polyp that appears in the large intestine and transforms into a malignant tumour.

The fecal occult blood test is especially indicated in people over 50 years old or with a family history of cancer in the digestive system, since it is a fundamental test to detect any anomaly in time and increase the possibilities of cure. It is also a test that is usually requested in patients who have ferropenic anemia (decreased iron values in the blood). Anemia or a low level of red blood cells can be the result of blood loss through the stool. 

The following determinations are made:

  • Hemogram. The hemogram is the part of the blood test that evaluates various parameters of the blood, such as red blood cells, defense cells or white blood cells, as well as platelets and clotting factors.
  • CA 19.9. This tumor marker allows differentiation between pancreatic and colon cancer from other diseases; but it is also used to monitor response to treatment in colon cancer and for early diagnosis of recurrences. 
  • SOH. This test aims to detect the presence of blood not visible to the naked eye in the stool. It is mainly used in the early detection of colon and rectal cancer (colorectal cancer), but it can also identify blood whose origin is located elsewhere in the digestive tract.

If the test result is positive (bloody stool), it will provide the doctor with valuable information about the need to continue monitoring the digestive system by performing new diagnostic tests such as gastroscopy or colonoscopy to identify the causes.

This brochure provides more information about the colorectal cancer prevention program in the Valencian Community.