How Effective Is The New Immunoassay Fecal Blood Occult Tests?

Posted on Mon, 3 Mar 2014

Medically reviewed by Ask A Doctor - 24x7 Medical Review Team

Mon, 3 Mar 2014 Answered on

Mon, 24 Mar 2014 Last reviewed on

Question : What are your thoughts on the new immunoassay fecal blood occult tests? I'm ready excellent things as far as specificity and sensitivity.

Answered by Dr. Vivek Chail (1 hour later)

Brief Answer: Please find detailed answer below Detailed Answer: Hi, Thanks for writing in to us. Fecal occult blood tests FOBT are one of the most basic and easy investigations to screen for blood in faeces that can be missed. There are recommendations made by the American Cancer Society (ACS) and I quote “Adults at average risk should begin colorectal cancer screening by age 50.” The 2001 guidelines provided 5 options: 1. FOBT annually 2. Flexible sigmoidoscopy every 5 years 3. Annual FOBT plus flexible sigmoidoscopy every 5 years 4. DCBE (double-contrast barium enema) every 5 years 5. Colonoscopy every 10 years." There are test kits manufactured by various suppliers and in my opinion they are standardized to be used in early detection of disease and prevent disease progression. However colonoscopy still remains the investigation of choice in people with high suspicion of colorectal neoplasms. Hope your query is answered. Do write back if you have any doubts. Regards, Dr.Vivek

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Vivek Chail (38 minutes later)

I was just curious about the iFOBT. I was reading studies that put the specificity at 87% and sensitivity at 90%. The studies didnt show increase accuracy with more than one sample. Just wanted to get an opinion.I think maybe I misunderstood your response the first time I read it but I would still like your opinion on the studies. Thank you Thanks anyway.

Answered by Dr. Vivek Chail (5 hours later)

Brief Answer: Please find detailed answer below Detailed Answer: Hi XXXX Thanks for writing back with an update. As you know fecal occult blood test has got the most important use in detecting colorectal cancers which a among one of the silent killers in the US. I reviewed a research article (2007) evaluating the use of iFOBT and it reveals ans I quote "The absolute sensitivity of iFOBT in recent studies has been shown to be roughly 60%". You may read the same as using the link below: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC0000/ Another research article (2013) from Japan says "Immunochemical fecal occult blood test (iFOBT) is widely used for colorectal cancer screening; however, its sensitivity is insufficient. It is reported that a fecal microRNA (miRNA) test (FmiRT) to detect colorectal cancer. Investigation shows a new colorectal cancer screening method combining iFOBT and FmiRT to improve the sensitivity compared with iFOBT alone." Further it is also stated "Levels of fecal miR-106a expression in iFOBT+ patients and iFOBT− patients were significantly higher than in healthy volunteers (P = 0.001). The sensitivity and specificity of FmiRT using miR-106a were 34.2% and 97.2%, and those of iFOBT were 60.7% and 98.1%, respectively. The overall sensitivity and specificity of the new screening method combining iFOBT and FmiRT were 70.9% and 96.3%, respectively. One quarter of colorectal cancer patients with false-negative iFOBT seemed to be true positive upon adding FmiRT using fecal miR-106a." The link for the second article is below: http://cebp.aacrjournals.org/content/22/10/1844.abstract Therefore newer techniques are evolving and being test by research before putting them into clinical practice. Hope your query is answered. Do write back if you have any doubts. Regards, Dr.Vivek

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar