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Some Basics

Information to Empower.

Please browse some of the sections and links I have assembled to inform yourself about the pros and cons of having health screening. I hope that this website will allow you to feel comfortable in deciding just how much health screening is right for you.

If you are uncertain about what you read or how to make up your mind, do please discuss the next time you see your  own GP. Generally, GPs are well placed not only to understand your personal needs and risk profile but also to weigh the benefits and risks of  screening tests


Remember many such tests are sometimes promoted by specialist doctors who can't help but have a rather one-sided view of the serious disease they specialise in. Much more importantly, you need to protect yourself from the advice of  people who want to profit from your anxiety.


NB:  for some people with a heightened risk of cancer or non malignant diseases , it does make sense to have screening with your GP or consultant doctor and to participate in national screening programmes. Check with your  GP whether for  you the benefit outweighs the risk.

Basic Facts About  Health Screening

Screening should be considered  worthwhile only if the disease screened for is truly preventable by earlier diagnosis. This  isn't as straightforward as you might think. For screening to work, we have to know for sure that the disease can be interrupted at a preliminary stage,  we have to have a reliable screening test and that test has to be safe for the patient.
Unfortunately, the lack of a complete understanding of  how diseases behave and the poor quality of many tests used in screening means that for many diseases screening is not possible.
Sadly, this doesn't stop enthusiasts from promoting screening when they ought to know better.
At best this is a case of wishful thinking. At worst this is unethical, especially where there is a vested interest in the promotion of screening.

Medical Record Analysis

The Myth that Screening is Harmless

When screening tests don't meet the strict standards for quality referred to as the Wilson & Junger criteria, which were laid down by the World Health Organisation in the  1960s, there is a very real risk that screening can lead to serious downsides.
There are many unintended consequences of poorly thought out screening tests. These include OVERDIAGNOSIS (where a cancer is found that would never have done any harm if left undetected) FALSE POSITIVES (where a screening tests  shows a cancer that turns out to be  a false alarm), MISDIAGNOSIS (false negative tests) and SIDE EFFECTS such as ANXIETY, PAIN, BLEEDING, SURGERY, SEPSIS and DEATH.
It is naive to believe that screening is without side effects. Usually these risks are very low, but they are hard to justify when the person screened was perfectly well and it is only the screening which caused the harm.
There is also the real problem that even where screening makes  sense, it is not always done right and this leads to justifiable dismay.
Finally, the idea that screening is always a good idea, gives rise to unwarranted, false expectations of  safety, which can only result in disappointment for many people.

Stethoscope on the Cardiogram

The Inverse Care Law

Those who most need services are the least likely to receive them. Screening and health checks are very much subject to this law. People who are well educated and well off use far more screening services than poor people. Their often excessive  access to tests draws  resources  away from the sort of curative services that are needed for less fortunate members of our society. There  is also a geographic unfairness in the provision of services so that affluent areas are provided with more and more  options, while the more remote and poor areas get left behind.

Doctor Using Digital Tablet

Some Good News!

There are examples of useful screening services in our country. These include kit tests for cancer of the colon and screening for people  at risk because of their medical history of illness, such as retinal screening in patients with diabetes.

Talk to your GP if you want to know what's right for you. 

Self testing is generally hazardous except as part of an organised national programme.

Doctor taking blood pressure of older patient
overdx cause and correction.png


Preventing Harm to You Through Screening

No...not doing more screening to prevent harm, but rather doing less...a lot less. 

Traditionally, doctors and scientists have talked about three levels of prevention in health care:Primary Prevention:

Doing things or stopping doing things (like taking more exercise or conversely stopping smoking or over using alcohol) so that you don't get a isease.Secondary Prevention: Doing things to limit the severity of disease usually by detecting and treating it early (like colon cancer  screening or testing newborn babies for inherited disorders of their metabolism)Tertiary Prevention: 
This means doing things to limit the impact of a disease that you already have, like rehabilitation after a stroke or cardiac rehabilitation after a heart attack.

In recent years, doctors have started talking about a fourth level of prevention.

Quaternary Prevention:

This is where the doctor does things to identify where a patient may be at risk of over diagnosis or over treatment, which could be harmful. For example, having blood tests like tumour markers for cancer or scans to check for brain aneurysms. While these tests can help some people, mostly they lead to unnecessary worry, medicine, further tests and even surgery, often with very negative health and economic consequences.

The diagram illustrates how over diagnosis can happen and how it can be tackled. This shows how patient and doctor fears as well as the vested interests of medical providers, science companies and drug firms tend to make us ill.

(WONCA Europe - Position Paper on  Overdiagnosis and Action to Be Taken. April 2018) World Organisation of National Colleges and Associations of GPs/Family Physicians.)

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