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Consult with Doctors on Health Checks Understand Limitations to Avoid Misdiagnosis

  • 2016.07.14

Like many other large cities around the world, Hong Kong is facing an ageing population and the increasing trend of younger generations afflicted by critical illness.  Consumers go through health checkup services in the hope that hidden diseases can be detected at an early stage.  This market demand has driven a wide variety of health checkup services with examination items commercialized and bundled up as "basic", "integrated" and "comprehensive" packages for consumers to choose according to their own needs.  Do consumers have sufficient medical knowledge to make any judgement on their real needs?  Are these examination items helpful in discovering hidden diseases?  Which tests are worthy to be conducted regularly?

The Consumer Council's report pointed out that without any clinical assessments or symptoms, many common health checkup items may not be very effective in detecting hidden diseases.  Moreover, they may show false negative or false positive results.  Consumers should understand which checkup items can help detect the hidden diseases, their functions, limitations and potential risks.  In addition, even for some health checkup packages with the same target groups, the scope of checkup items, the functions, and the prices may vary.  Even though certain basic checkup items are similar, the price difference could be as much as nearly $1,000.  Consumers should choose with prudence.

The Consumer Council surveyed information in a number of health checkup packages provided by different organisations.  The survey showed that among the health checkup packages reviewed, only some of them indicated that the checkup reports would be explained by doctors.  Some others stated that explanation would be made by "designated" persons or "medical staff" such as medical laboratory technologists or nurses.  The Council stressed that laboratory tests should be combined with clinical checkups conducted by doctors to give meaningful analysis and risk assessments.  Therefore, laboratory test results should be assessed by a doctor, whether they are normal or not, to avoid misinterpretation.

The Council sought expert advice from the Department of Health (DH), the Hong Kong College of Pathologists (HKCPath), and the Hong Kong Medical Association (HKMA) on the health checks.  The numerous checkup items and expert advice were then categorized into 5 types, namely blood tests, checkups using medical equipment, marker tests targeting to cancers screening, checkups for gynecological diseases and colorectal cancer screening, to help consumers understand the functions, limitations and potential risks of different health checks.

Quoting expert opinion, the Council's report pointed out that health checkup packages commonly found in the market are usually "unconditional", i.e. checkups are not performed according to medical assessments or clinical needs.  Instead, they are provided to people who did not show any clinical symptoms as all-inclusive checkups and laboratory tests in the hope of detecting hidden diseases at an early stage.  However, these may not serve the purpose. Some regular laboratory tests are only suitable for confirmation or monitoring purposes in patients with confirmed diseases.  If they are used on the general population with no symptoms to screen for diseases of very low prevalence, the proportion of positive results that truly indicate patients with the disease can be less than 20%.

Under the circumstances of no clinical assessments or symptoms, many common health checkup items may not be able to effectively detect hidden diseases.  If "Resting or Exercise ECG", an examination for coronary artery disease, is used on people without any symptoms, the rate of false positive is high.  Using "Chest X-ray" as a screening tool for lung cancer, due to its poor sensitivity, may result in high false negative rate.

Regarding blood tests, even if test results of "Complete Blood Pictures/Complete Blood Count" and "Erythrocyte Sedimentation Rate (ESR)" exceeded the normal range, the test results alone will not give sufficient information to make a medical decision when applied on person without any symptoms.  When "Blood Lipid" for cardiovascular risk assessment is applied, other factors such as the person's age, blood pressure and smoking habit should also be taken into consideration.

Cancer is a health concern for many consumers.  Some health checkup packages will add "Tumor Marker Test" as an optional item for consumers.  Some even combined various tests into special packages targeting on cancer detection with the price difference of up to nearly $1,000.  Consumers should note that "Tumor Marker" is a special substance in the blood and its level may be elevated when a certain type of cancer is present.  It is generally used by doctors for assisting diagnosis and monitoring of treatment progress, but not as an ideal test for screening cancers for the average consumers.  Currently, there is no "Tumor Marker" sufficiently sensitive and specific to be used on its own for cancer screening purposes.

Among the gynecological examinations, the benefit of using "mammography" in population-based screening of breast cancer for women without symptoms is still undetermined.  As for women with higher risk of breast cancer, they should consult doctors before deciding on whether to take the breast cancer screening test.

Potential Risks of Some Health Checkup Items

Some of the checkup items may involve radiation or are invasive.  For example, radiation is produced during X-ray examination and could impact negatively on health if taken excessively.  "Colonoscopy" is an invasive procedure involving certain risks and possible complications include abdominal discomfort, bowel perforation or bleeding.  Adverse reaction to the sedative used during the process may also occur in some people.  Without a doctor's instruction, consumers should not casually take these examinations.  

Screening Tests that Help Prevent Diseases

Some health checkup items have proven effectiveness in prevention and detection of certain diseases.  For example, people aged over 45 or at high risk of diabetes can be screened periodically for diabetes using "Fasting Glucose Test".  With Colorectal Cancer being the most common cancer in Hong Kong, the medical sector recommends people between the ages of 50 and 75 without any symptoms to consult their family doctors and consider undertaking the non-invasive "Faecal Occult Blood" test annually or biannually, or the "Sigmoidoscopy" every 5 years, or "Colonoscopy" every 10 years.  Women between the ages of 25 and 64 who ever had sex should also have regular cervical cancer screening for early detection and treatment of cervical precancerous lesions.   

The Council suggests consumers to, before taking any health checkups, consult their family doctors who will base on clinical diagnosis and assessment with due consideration of different factors such as their age, past medical history, personal habits, physical conditions, and family history to determine whether any tests are required.  Suitable health check-up items should be recommended according to the individual's health condition.  Test results should be interpreted and explained by doctors, based on their professional assessment.