An Electrocardiogram (ECG or EKG) is essentially a snapshot of your heart's electrical activity. Think of it as a "wiring check" for your body’s most important pump.
Echocardiogram
An Echocardiogram (often called an "echo") is essentially an ultrasound for your heart. While an ECG (which you asked about earlier) measures electrical signals,
Ultrasound
That is a broad (but fascinating) topic! Depending on what you’re looking for, ultrasound can range from seeing a baby for the first time to high-tech industrial testing.
X-ray
an X-ray uses electromagnetic radiation. Because X-rays have a very short wavelength and high energy, they can pass through soft tissues but are absorbed by denser materials.
Hormone test/thyroid test
A thyroid test is a common blood panel used to check how well your thyroid gland—the butterfly-shaped organ in your neck—is regulating your metabolism.
Blood test
Whether you're going for a routine checkup or investigating a specific symptom, blood tests are the most common way for doctors to "peek under the hood" of your body.