Doctors nationwide have been seeing a definite uptick in patients going to hospitals and imaging centers to have various screening tests done. The most common are heart and lung CT exams and sometimes ultrasound tests to evaluate for blockages in the arteries in the neck and legs. The scans typically have out-of-pocket costs in the $49 to $99 range and are not covered by insurance. They are promoted to identify early heart disease, artery blockages and/or lung cancer.
People usually ask for these tests after seeing them advertised by the facilities doing the testing. While screening can save lives, it can also lead to unnecessary additional testing and worry for patients. Many of these scans are done inappropriately without a prior discussion of their utility and limitations and to determine if there is actually an evidence-based need to do the test. 
It is important to know the risks of any screening test including false positives (seeing things on the scans that have no medical significance, yet may cause a great deal of angst for patients), false negatives (not seeing something that is actually there), as well as exposure to radiation.
The coronary artery calcium (CAC) scoring test involves doing a CT scan to see if calcium deposits are present in the walls of the coronary arteries that supply oxygen and other nutrients to the heart. The test produces a calcium score that may indicate a person has coronary artery disease, with an increased risk of suffering a heart attack. 
It’s important to realize that this test is but one piece of evidence to determine a person’s overall risk for heart disease. Patients should contact their primary medical provider before scheduling one of these tests to calculate their risk of heart disease. Risk is based on medical & family history, age, sex, blood pressure, cholesterol values, presence of diabetes and smoking history. Once their risk is assessed, the need for a CAC or other test can be determined.
People who have less than a ten percent risk of having a heart attack over the next 10 years (low risk), or are less than 40 years old don’t need the test. The test probably has the most utility in those with an intermediate risk of heart disease (10 to 20 percent chance over the next ten years). A higher CAC can sometimes make us lean toward being more aggressive with lifestyle changes and medications to prevent a first heart attack. Those with a risk greater than 20 percent are usually treated aggressively, no matter what their CAC score.
CT lung cancer screening is another test that should only be performed on specific patients to help prevent premature death from lung cancer. The U.S. Preventative Services Task Force (USPSTF) recommends yearly screening in patients who: (1) are between 55 and 80 years of age, (2) have a 30 pack-year smoking history (smoked a pack a day for 30 years, 2 packs a day for 15 years, etc.), and (3) currently smoke or have quit smoking in the last 15 years. There is a low likelihood of developing lung cancer and dying from it in patients who do not meet these criteria.
Ultrasound screening for blockages in the leg arteries is usually a blood pressure measurement comparing the pressure in the ankle vs that in the arm. The evidence for screening recommendations remains controversial. The American College of Cardiology and American Heart Association jointly recommend screening if you are over 65, are over 50 with risk factors or a family history of blockages, or less than 50 with diabetes and another risk factor for blockages. Ultrasound screening for blockages in the carotid arteries in the neck is not recommended by any major professional groups.
I’ve had many patients sign up for multiple screening tests at the same time thinking as long as they’re getting one scan, why not get all that are available? Once again, there are risks to having an inappropriate scan, including radiation exposure, as well as seeing things on the scan that likely have no medical significance. This can lead to worry and additional testing. I would recommend before doing any of these scans that you talk to your doctor first. If you do take advantage of one or more of these tests, make sure the facility staff takes your medical history to determine if you have risk factors that meet the criteria for doing the test(s).