What is the Difference Between Screening and Diagnosis?

Screening vs Diagnostic Testing: What You Need to Know

Screening and diagnosis are often used interchangeably. However, they are different and serve different purposes. While doctors suggest screening for early detection of a disease, diagnosis and diagnostic tests allow doctors to create a treatment plan. Let us keep reading to know them in detail.

Diagnosis vs Screening: Key Differences

Here are the key differences between diagnosis and screening you should know about:

From the above table, we can see that screening and diagnosis have different goals when it comes to understanding any health condition. While screening detects irregularities, diagnostic tests establish a diagnosis based on the test.

What is a Screening test?

A screening test refers to a medical test or procedure that helps in the identification of individuals who might have a specific disease or condition, even in cases where they don't yet have symptoms. Screening tests refer to the preliminary assessment tests, not a definitive diagnosis, and focus on sorting individuals into those who tend to have the disease and those who do not tend to. Those who test positive are then referred for further diagnostic testing.

Examples of Screenings

The examples of Screenings are Cancer Screenings, which include mammography(for breast cancer), faecal occult blood tests (for colorectal cancer), pap tests and HPV tests(for cervical cancer) and prostate-specific antigen (PSA) tests(for prostate cancer).

What is a Diagnostic test?

A diagnostic test refers to a process that is used in medicine to find out the presence, extent or nature of a disease or learning difficulty. In medicine, it aids doctors in finding out what condition a patient has, thus helping guide treatment decisions.

Examples of Diagnostic Tests

Examples include blood tests, imaging scans, and endoscopies. Screening tests include Laboratory Tests(like Urinalysis, Complete Blood Count (CBC), etc), Imaging Tests(X-rays, CT scans, etc), Endoscopies (Colonoscopy, Gastroscopy, etc) and other diagnostic tests. A colonoscopy is often used as a primary screening tool or as a follow-up diagnostic procedure if a stool test returns a positive result.

What are the Different Types of Screening Tests?

There are different types of screening tests, each with its own purpose. Let us discuss them below:

Mammography

Illness related to the breasts is most common among women. Therefore, to aid in early detection, doctors use a low-dose X-ray, called a mammogram, to detect any abnormalities.

Doctors generally recommend that women opt for a yearly mammogram after the age of 40.  

Colonoscopy

Doctors recommend a colonoscopy to screen for colorectal cancer in asymptomatic people. This test also helps in detecting polyps (precancerous growths) and investigates symptoms like rectal bleeding, abdominal pain, or changes in bowel habits.

If the test finds any tumours, then doctors recommend further diagnostic tests to confirm the disease. The test can prevent certain forms of colon cancer by detecting polyps early.

Pap Smear

Cervical cancer can be fatal if detected in its advanced stage. However, a Pap smear test is a lifesaving screening test for detecting any abnormal cells, which may become cancerous in the future.

Doctors recommend that anyone between the ages of 21 and 30 should screen for cervical cancer once every 3 years.

What are the Different Types of Diagnostic Tests?

Here are the most common types of diagnostic tests available:

Complete Blood Count Test

The CBC, or complete blood count test, provides your doctor with a blueprint of your body’s functioning. This test helps to diagnose many diseases, such as anaemia and infections. It measures the contents of your blood, such as red blood cells (RBCs), white blood cells (WBCs), platelets and leukocytes.

Electrocardiogram

This diagnostic test measures your heart’s electrical activity. This is done by repeated cardiac cycles. The purpose of this test is to find out how well your heart is working. This test can detect arrhythmia, coronary heart disease and heart attacks.
 

Imaging Tests

Imaging tests use various kinds of energy to gather data and produce images of the inside of your body. For example, X-rays use ionising radiation, and ultrasound tests use high-energy sound waves to collect data.

These diagnostic tests can detect fractures and injuries. Moreover, it can detect the presence of cancerous cells as well.

Screening and diagnosis are different in their ways. One helps in detecting signs and symptoms of diseases, while the latter focuses on establishing the proper affected areas and causes of the disease. Although they are different, they serve an important role in analysing your health issues.

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