Overview: Screening

Introduction

For lots of people, screening tests are just a normal part of health care. Sometimes your health insurer will cover the costs, sometimes you will have to pay yourself.

But the question of which screening tests do or don’t make sense for you and when to have them done is a personal one. This information is intended to help you decide.

At a glance

• Some screening tests help prevent disease.
• Others can make the disease easier to treat or improve the outlook.
• But there are no health benefits for many screening tests, and some even cause more harm than good.
• Screening tests are voluntary.
• The important thing is to be well-informed about the pros and cons of the specific test.

Getting the information you need to make the right decision for you

You have to give your consent before a screening test. Whether or not you have the test is completely up to you. Different people have different approaches. Some just trust their doctor and don’t ask many questions. Others want to find out as much as possible about the advantages and disadvantages of the test.

Taking a closer look is certainly a good idea. There are some screening tests that can prevent disease or at least simplify treatment and improve the chances of recovery. But there are also lots of tests that haven’t been proven to provide any health benefits at all. Some actually cause more harm than good.

Asking yourself the following questions can help you make a good decision:

• Does the disease really pose a risk for you?
• Can the test prevent the disease or can it “just” detect it earlier so that treatment is more effective?
• What are the potential disadvantages of the test?
• Do you have to pay for the test yourself?

The law requires doctors to go through these questions with you in detail before the test.

Question 1: Does the disease really pose a risk for you?

Some diseases are very common, and some are very rare. Many are harmless and go away on their own; others can be fatal. Some only affect the elderly, and some start at a young age.

People have different ideas about the risk a specific disease poses for them. It often depends on their personal situation and their family’s and friends’ experiences.

Even if a disease is widespread and dangerous, it doesn’t mean that it poses a risk for everybody. Your individual risk can depend on things like your age or illnesses that you have had. Some simple statistics can help to assess this risk.

There are three main factors that determine how threatening you feel a specific disease may be. They are:

• How likely is it that you will develop the disease?
• How could it affect you?
• How does the risk posed by the disease compare to other risks in your life?

Question 2: Does the test prevent the disease or detect it earlier?

If the test detects abnormal changes that could later develop into the disease and they can be remedied, it prevents the disease. Strictly speaking, only this type of test is a “preventive test.” But just certain screening tests can do this, like colonoscopies.

The question of whether a screening test is worth doing depends on the specific disease and the screening method. Another important point to consider is whether treatment of a disease is really more effective because it was detected earlier.

A good way of telling whether a screening test is beneficial is whether good-quality studies have proven its benefits. But many of them don’t actually have proven benefits. Many of the screening tests available (almost all of what are known as “individual health care services” or “individuelle Gesundheitsleistungen” (“IGeL), for instance) haven’t even been tested in suitable trials. Plus, in some cases good-quality research has shown that the tests can’t improve your chances of recovery. One example is ovarian cancer screening.

Question 3: What are the potential disadvantages of the test?

Many people find this question a little confusing to start with. They take it for granted that screening is always a good thing or, at least, doesn’t do any harm.

But, as with all things medical, screening tests can have disadvantages as well as advantages. Often, though, the disadvantages aren’t immediately clear.

One simple example of a disadvantage is the injuries or complications that can result from taking blood for a test or conducting a colonoscopy. A slightly more complex example is the harm that can be caused by the results of the test. This can happen when, for instance, a test result suggests you have the disease but it turns out to be a false alarm.

The potential disadvantages can be divided into the following categories:

• Disadvantages arising from the actual test – like infections or injuries.
• Disadvantages arising from the need for additional testing when a test delivers an incorrect result.
• Disadvantages arising from a diagnosis that doesn’t help improve the person’s chances of recovery (overdiagnosis).

How common and relevant these disadvantages are depends on the disease and the screening method. Sometimes the possible disadvantages are harmless, but sometimes they could be a good reason not to have the test done.

A screening test makes sense if the benefit it offers outweighs any possible harm. But that too depends on your own personal opinions.

Question 4: Do you have to pay for the test yourself?

Public (statutory) health insurers offer a wide range of screening tests free of charge. Whenever a new service is to be added to their portfolio, it first has to be assessed to determine its potential benefits and harm. It is only included if there are more benefits. This has been standard practice for several years and gives people a certain amount of protection against tests that offer no benefits or, worse still, are harmful.

Having said that, there are some tests that insurers still cover which, for example, were added to the portfolio in the 1970s without being thoroughly assessed. They include examination of the prostate or colon by touch (palpation) as part of general cancer screening.

In Germany, doctors also offer a range of additional tests (known as “individual health care services” or “individuelle Gesundheitsleistungen” (IGeL)). Often, it’s not possible to be sure of their advantages or disadvantages. People have to pay for IGeL screening tests themselves. Doctors are required to provide comprehensive information about the advantages and disadvantages of the IGeL tests too so it makes sense to ask whatever you want to know.

What guidance is available to help you make your decision?

Before you have a test, the doctor always has to tell you about the advantages and disadvantages and what the results could mean for you. They base this information on scientific data.

Germany has three large-scale cancer screening programs. Invitations to take part are sent out regularly by post. They are for:

• Breast cancer screening
• Colorectal cancer screening
• Cervical cancer screening

The invitation letters also include information on the main points mentioned above to help people decide whether to participate. Data protection, your rights, the examination method and quality assurance are covered in the letter too.

informedhealth.org has information on the following tests, which good-quality research has proven to be of benefit:

• Colorectal cancer screening
• Breast cancer screening
• Cervical cancer screening
• Abdominal aortic aneurysm (AAA) screening

There are no clear conclusions about the relative advantages and disadvantages of the following screening tests:

• Skin cancer screening
• Prostate cancer screening, including PSA tests
• Ultrasound screening for ovarian cancer
• Glaucoma screening

Sources

• Andreae S, Avelini P, Berg M et al. Lexikon der Krankheiten und Untersuchungen. Stuttgart: Thieme; 2008.

• Bundesministerium für Gesundheit (BMG). Online-Ratgeber Krankenversicherung: Welche Früherkennungsuntersuchungen werden empfohlen? 2016.

• Gemeinsamer Bundesausschuss (G-BA). Früherkennung von Krankheiten. 2021.

• Giersiepen K, Hense HW, Klug SJ et al. Entwicklung, Durchführung und Evaluation von Programmen zur Krebsfrüherkennung. Z Arztl Fortbild Qualitatssich 2007; 101(1): 43-49. [PubMed: 17458364]

• Kasper DL, Fauci AS, Hauser SL et al. Harrison's Principles of Internal Medicine. New York: McGraw-Hill; 2015.

• Petticrew MP, Sowden AJ, Lister-Sharp D et al. False-negative results in screening programmes: systematic review of impact and implications. Health Technol Assess 2000; 4(5): 1-120. [PubMed: 10859208]

• Pschyrembel Online. 2022.

• UK National Screening Committee (NHS). Criteria for appraising the viability, effectiveness and appropriateness of a screening programme. 2015.

• Wilson JM, Jungner G. Principles and practice of screening for disease. (Public Health Papers; No. 34). J R Coll Gen Pract 1968; 16(4): 318.

• World Health Organization (WHO). Screening programmes: a short guide. Increase effectiveness, maximize benefits and minimize harm. 2020.

• IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

  Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. informedhealth.org can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

  Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.