Types of Blood Tests
Some of the most common blood tests that doctors
order are:
- Complete blood count (CBC)
- Blood chemistry tests
- Blood enzyme tests
- Blood tests to assess heart disease risk
Complete Blood Count
The CBC is one of the most common
types of blood test. It's often done as part of a routine checkup.
A CBC measures many different parts of your blood
(as described below). This test can help detect blood diseases and disorders.
These include
anemia,
infection, clotting problems, blood cancers, and immune system disorders.
Red Blood Cells
Red blood cells carry oxygen from your lungs to the
rest of your body. Abnormal red blood cell levels may be a sign of anemia,
dehydration (too little fluid in the body), bleeding, or another disorder.
White Blood Cells
White blood cells are part of your immune system,
which fights infections and disease. Abnormal white blood cell levels may be a
sign of infection, blood cancer, or an immune system disorder.
A CBC measures the overall number of white blood
cells in your blood. A differential count looks at the amounts of different
types of white blood cells in your blood.
Platelets
Platelets (PLATE-lets) are blood cells that help
your blood clot. They stick together to seal cuts or breaks and stop bleeding.
Abnormal platelet levels may be a sign of a bleeding disorder (not enough
clotting) or a thrombotic disorder (too much clotting).
Hemoglobin
Hemoglobin (HEE-muh-glow-bin) is an iron-rich
protein in red blood cells that carries oxygen. Abnormal hemoglobin levels may
be a sign of anemia,
sickle
cell anemia,
thalassemia
(thal-a-SE-me-ah), or other blood disorders.
If you have diabetes, excess glucose in your blood
can attach to hemoglobin and raise the level of hemoglobin A1c.
Hematocrit
Hematocrit (hee-MAT-oh-crit) is a measure of how
much space red blood cells take up in your blood. A high hematocrit level might
mean you're dehydrated. A low hematocrit level might mean you have anemia.
Abnormal hematocrit levels also may be a sign of a blood or bone marrow
disorder.
Mean Corpuscular Volume
Mean corpuscular (kor-PUS-kyu-lar) volume (MCV) is a
measure of the average size of your red blood cells. Abnormal MCV levels may be
a sign of anemia or thalassemia.
Blood Chemistry Tests/Basic Metabolic Panel
The basic metabolic panel (BMP) is a group of tests
that measure different chemicals in the blood. These tests usually are done on
the fluid (plasma) part of blood. The tests can give doctors information about
your muscles, including the heart; bones; and organs, such as the kidneys and
liver.
The BMP includes blood glucose, calcium,
electrolyte, and kidney tests. Some of these tests require you to fast (not eat
any food) before the test, and others don't.
Blood Glucose
Glucose is a type of sugar that the body uses for
energy. Abnormal glucose levels in your blood may be a sign of diabetes.
For some blood glucose tests, you have to fast
before your blood is drawn. Other blood glucose tests are done after a meal or
at any time with no preparation.
Calcium
Calcium is one of the most important minerals in the
body. Abnormal calcium levels in the blood may be a sign of kidney problems,
bone disease, thyroid disease, cancer, malnutrition, or another disorder.
Electrolytes
Electrolytes are minerals that help maintain fluid
levels and acid-base balance in the body. They include sodium, potassium,
bicarbonate, and chloride.
Abnormal electrolyte levels may be a sign of
dehydration, kidney disease, liver disease,
heart
failure,
high
blood pressure, or other disorders.
Kidneys
Kidney tests measure levels of blood urea nitrogen
(BUN) and creatinine. Both of these are waste products that the kidneys filter
out of the body. Abnormal BUN and creatinine levels may be signs of a kidney
disease or disorder.
Blood Enzyme Tests
Enzymes are chemicals that help control different
reactions in your body. There are many blood enzyme tests. This section focuses
on blood enzyme tests used to check for
heart
attack.
These include creatine kinase (CK) and troponin
tests.
Creatine Kinase
When muscle or heart cells are injured, CK (a blood
product) leaks out, and its levels in your blood rise. There are different
types of CK. CK-MB is released when the heart muscle is damaged.
High CK levels can mean that you've had muscle
damage in your body. High levels of CK-MB can mean that you've had a heart
attack. Doctors order CK tests (such as CK-MB) when patients have chest
pain or other
heart
attack signs and symptoms.
Troponin
This is a muscle protein that helps your muscles
contract. Blood levels of troponin rise when you have a heart attack. For this
reason, doctors often order troponin tests along with CK-MB tests when patients
have chest pain or other heart attack signs and symptoms.
Blood Tests To Assess Heart Disease Risk
Abnormal levels of certain chemicals in the blood
may mean that youre at higher risk for heart disease. Your doctor may
want to test the levels of these chemicals to assess your risk and to suggest
ways to reduce it.
Lipoprotein Panel
This test can help show how high your risk is for
coronary
heart disease. A lipoprotein panel looks at substances in your blood that
carry cholesterol.
The test gives information about your:
- Total cholesterol.
- LDL ("bad") cholesterol. This is the main source
of cholesterol buildup and blockages in the arteries.
- HDL ("good") cholesterol. This type of
cholesterol helps decrease blockages in the arteries.
- Triglycerides. These are another form of fat in
your blood.
A lipoprotein panel measures the levels of HDL and
LDL cholesterol and triglycerides in your blood. Abnormal cholesterol and
triglyceride levels may be signs of increased risk for coronary heart
disease.
Most people will need to fast for 9 to 12 hours
before a lipoprotein panel.
High-Sensitivity C-Reactive Protein
This is a fairly new test for heart disease risk. It
looks at blood levels of C-reactive protein (CRP). High CRP blood levels can be
a sign of inflammation.
Doctors use standard CRP tests to check for
inflammation and autoimmune diseases. Your doctor may order an hs-CRP test,
along with other tests, to see whether youre at increased risk for heart
disease.
However, CRP tests arent routinely done,
because its still unclear how useful they are for showing heart disease
risk.
Homocysteine
High levels of this chemical in the blood can mean
that youre at higher risk for heart attack or stroke. This isnt a
routine test for heart disease risk. But some doctors may use it, a long with
other tests, if they think youre at increased risk. |