This is a medical question of type : exams and tests 
 How to diagnose Angina ? 
 The most important issues to address when you go to the doctor with chest pain are:
                
What's causing the chest pain
                
Whether you're having or are about to have a heart attack
                
Angina is a symptom of an underlying heart problem, usually coronary heart disease (CHD). The type of angina pain you have can be a sign of how severe the CHD is and whether it's likely to cause a heart attack.
                
If you have chest pain, your doctor will want to find out whether it's angina. He or she also will want to know whether the angina is stable or unstable. If it's unstable, you may need emergency medical treatment to try to prevent a heart attack.
                
To diagnose chest pain as stable or unstable angina, your doctor will do a physical exam, ask about your symptoms, and ask about your risk factors for and your family history of CHD or other heart diseases.
                
Your doctor also may ask questions about your symptoms, such as:
                
What brings on the pain or discomfort and what relieves it?
                
What does the pain or discomfort feel like (for example, heaviness or tightness)?
                
How often does the pain occur?
                
Where do you feel the pain or discomfort?
                
How severe is the pain or discomfort?
                
How long does the pain or discomfort last?
                
Diagnostic Tests and Procedures
                
If your doctor thinks that you have unstable angina or that your angina is related to a serious heart condition, he or she may recommend one or more tests.
                
EKG (Electrocardiogram)
                
An EKG is a simple, painless test that detects and records the hearts electrical activity. The test shows how fast the heart is beating and its rhythm (steady or irregular). An EKG also records the strength and timing of electrical signals as they pass through the heart.
                
An EKG can show signs of heart damage due to CHD and signs of a previous or current heart attack. However, some people who have angina have normal EKGs.
                
Stress Testing
                
During stress testing, you exercise to make your heart work hard and beat fast while heart tests are done. If you cant exercise, you may be given medicine to make your heart work hard and beat fast.
                
When your heart is working hard and beating fast, it needs more blood and oxygen. Plaque-narrowed arteries can't supply enough oxygen-rich blood to meet your heart's needs.
                
A stress test can show possible signs and symptoms of CHD, such as:
                
Abnormal changes in your heart rate or blood pressure
                
Shortness of breath or chest pain
                
Abnormal changes in your heart rhythm or your heart's electrical activity
                
As part of some stress tests, pictures are taken of your heart while you exercise and while you rest. These imaging stress tests can show how well blood is flowing in various parts of your heart. They also can show how well your heart pumps blood when it beats.
                
Chest X Ray
                
A chest x ray takes pictures of the organs and structures inside your chest, such as your heart, lungs, and blood vessels.
                
A chest x ray can reveal signs of heart failure. It also can show signs of lung disorders and other causes of symptoms not related to CHD. However, a chest x ray alone is not enough to diagnose angina or CHD.
                
Coronary Angiography and Cardiac Catheterization
                
Your doctor may recommend coronary angiography (an-jee-OG-ra-fee) if he or she suspects you have CHD. This test uses dye and special x rays to show the inside of your coronary arteries.
                
To get the dye into your coronary arteries, your doctor will use a procedure called cardiac catheterization (KATH-e-ter-ih-ZA-shun).
                
A thin, flexible tube called a catheter is put into a blood vessel in your arm, groin (upper thigh), or neck. The tube is threaded into your coronary arteries, and the dye is released into your bloodstream.
                
Special x rays are taken while the dye is flowing through your coronary arteries. The dye lets your doctor study the flow of blood through your heart and blood vessels.
                
Cardiac catheterization usually is done in a hospital. You're awake during the procedure. It usually causes little or no pain, although you may feel some soreness in the blood vessel where your doctor inserts the catheter.
                
Computed Tomography Angiography
                
Computed tomography (to-MOG-rah-fee) angiography (CTA) uses dye and special x rays to show blood flow through the coronary arteries. This test is less invasive than coronary angiography with cardiac catheterization.
                
For CTA, a needle connected to an intravenous (IV) line is put into a vein in your hand or arm. Dye is injected through the IV line during the scan. You may have a warm feeling when this happens. The dye highlights your blood vessels on the CT scan pictures.
                
Sticky patches called electrodes are put on your chest. The patches are attached to an EKG machine to record your heart's electrical activity during the scan.
                
The CT scanner is a large machine that has a hollow, circular tube in the middle. You lie on your back on a sliding table. The table slowly slides into the opening of the machine.
                
Inside the scanner, an x-ray tube moves around your body to take pictures of different parts of your heart. A computer puts the pictures together to make a three-dimensional (3D) picture of the whole heart.
                
Blood Tests
                
Blood tests check the levels of certain fats, cholesterol, sugar, and proteins in your blood. Abnormal levels may show that you have risk factors for CHD.
                
Your doctor may recommend a blood test to check the level of a protein called C-reactive protein (CRP) in your blood. Some studies suggest that high levels of CRP in the blood may increase the risk for CHD and heart attack.
                
Your doctor also may recommend a blood test to check for low levels of hemoglobin (HEE-muh-glow-bin) in your blood. Hemoglobin is an iron-rich protein in red blood cells. It helps the blood cells carry oxygen from the lungs to all parts of your body. If your hemoglobin level is low, you may have a condition called anemia (uh-NEE-me-uh).