Stool Tests Cannot Replace Diagnostic, Preventive Colonoscopy: Specialists

Colorectal surgeons say stool tests are for general screening and can’t replace colonoscopy to diagnose colorectal cancer when patients have symptoms. Polyps can be removed before turning cancerous, making it both a diagnostic and preventive procedure.

From left to right: Dr Ho Shiaw Hooi (Consultant Gastroenterologist & Physician), Dr Luqman Mazlan (Consultant General & Colorectal Surgeon), Dr Yeap Chee Loong (Consultant General, Upper Gastrointestinal & Obesity Surgeon), and Dr Chong Hoong Yin (Consultant General & Colorectal Surgeon). Photo by Hospital Picaso.

KUALA LUMPUR, July 22 — Colonoscopy remains the gold standard for detecting colorectal cancer, with stool-based tests serving only as an initial screening tool rather than a replacement for colonoscopy, colorectal surgeons said.

Dr Luqman Mazlan, a consultant general and colorectal surgeon at Hospital Picaso, said stool tests can help identify people who require further investigation but cannot diagnose colorectal cancer on their own.

“There’s no test more accurate than a colonoscopy at the moment,” Dr Luqman said during a media engagement on gut health last Thursday.

While newer technologies such as stool DNA testing may become more widely available, Dr Luqman said they remain expensive and, even when highly sensitive, are not specific enough to establish a diagnosis. Patients with abnormal stool test results still require colonoscopy to determine the cause.

“A bowel stool test just tells you there’s blood,” Dr Luqman said. “It doesn’t tell you what it is. If it’s positive, you have to do a scope.”

During Parliament’s Public Accounts Committee (PAC) inquiry into rising medical insurance premiums and private hospital charges, insurance CEOs and chairmen questioned the frequency of endoscopic procedures (particularly combined upper and lower scopes) and gastric polypectomy (procedure to remove stomach polyps), suggesting that stool testing should precede many gastrointestinal scopes.

Depending on a patient’s symptoms and risk factors, doctors may recommend blood tests, stool tests, imaging, colonoscopy, or oesophagogastroduodenoscopy (OGDS), also known as gastroscopy, to determine the underlying cause, said Hospital Picaso consultants.

The colorectal surgeons maintained, however, that stool tests are intended for screening and cannot replace colonoscopy for diagnosis.

Unlike stool tests, colonoscopy allows physicians not only to detect cancer but also to identify and remove adenomatous polyps before they become malignant, making it both a diagnostic and preventive procedure.

Dr Chong Hoong Yin, consultant general and colorectal surgeon at Hospital Picaso, said colorectal screening is particularly important because some cancers develop gradually from polyps that can be detected and removed before they become malignant.

“By the time symptoms become obvious, some conditions may already be more advanced,” Dr Chong said. 

“This is why screening is so important in colorectal care. A colonoscopy can help doctors detect abnormalities early, and in some cases, remove polyps before they progress. Early detection is not just about finding disease sooner. It is about giving patients more options before treatment becomes more complex.”

According to Dr Luqman, current Malaysian guidelines recommend that adults at average risk undergo their first screening colonoscopy at age 50, followed by repeat examinations every 10 years if no abnormalities are found.

He said people with a first-degree relative diagnosed with colorectal cancer should begin screening 10 years before the age at which their affected relative developed the disease.

People with multiple affected first-degree relatives should also be assessed for hereditary colorectal cancer syndromes, which may require genetic testing and earlier surveillance.

Persistent Digestive Symptoms Warrant Investigation

Beyond colorectal cancer screening, gastroenterologists and upper gastrointestinal specialists at the event urged people not to ignore persistent digestive symptoms that could signal cancers elsewhere in the digestive tract.

Dr Ho Shiaw Hooi, consultant gastroenterologist and physician at Hospital Picaso, said the gastrointestinal tract extends about seven metres from the mouth to the anus, with conditions affecting any part of the digestive tract capable of causing symptoms.

“Any problem along this tract, the body will send signals to you,” Dr Ho said.

He said persistent acid reflux, stomach pain, gastrointestinal bleeding, changes in bowel habits, and unexplained weight loss should all prompt medical evaluation.

While reflux is common, Dr Ho said persistent symptoms, particularly when accompanied by difficulty swallowing, warrant further investigation because they may indicate Barrett’s oesophagus, a precancerous condition that can progress to oesophageal cancer.

He also urged people not to dismiss gastrointestinal bleeding.

“A lot of times, if it is coming from below, people brush it off by saying that it’s just haemorrhoids,” Dr Ho said. “But because colon cancer is the number one cancer in men and number two in women, we cannot just brush it off like that.”

A persistent change in bowel habits, even if still considered “normal” in frequency, should also be assessed if it differs from a person’s usual pattern, particularly if accompanied by loose stools or mucus, he said.

Dr Yeap Chee Loong, consultant gastrointestinal and obesity surgeon at Hospital Picaso, said many Malaysians delay seeking medical care because they attribute persistent symptoms to “gastric” or haemorrhoids.

He said stomach pain can originate from many organs, including the oesophagus, stomach, pancreas, liver, gallbladder, kidneys, heart, lungs, and colon, making self-diagnosis potentially dangerous.

“Patients self-diagnose themselves. They delay seeing a doctor, and six months later they are found to have stage three stomach cancer, stage three pancreatic cancer, or oesophageal cancer,” Dr Yeap said. 

“These symptoms should not be dismissed. People should seek medical advice early.”

Sources

Stool Tests Cannot Replace Diagnostic, Preventive Colonoscopy: Specialists (CodeBlue, 22 July 2026)

Always Bloated, Always Tired? Hospital Picaso Doctors Explain When Gut Symptoms Deserve a Closer Look (The Stoly, 17 July 2026)

Is your gut trying to tell you something? (Free Malaysia Today, 19 July 2026)