What Your Blood Tests Really Mean

When the doctor orders blood tests (also called lab tests, blood profile/ panel), she or he is checking for certain things. The most common tests are CBC (complete blood count), basic complete blood panel, and UA (urinalysis). The CBC checks the body’s WBCs (white blood cells) and RBCs (red blood cells). In the lab the cells are examined for size, shape, and number. The WBCs may tell if you may have some type of infection or leukemia(cancer of the white cells). The RBCs carry oxygen to the rest of the body. This is done by hemoglobin, which is carried inside the RBCs.  Some inherited diseases, such as sickle cell
anemia and thallassemia, can be identified by abnormal RBC shape and size. Also included in the CBC is a platelet count. Platelets are cells that help your blood to clot, for instance to stop the bleeding after a flesh wound.

The basic complete blood panel measures many different things. Included in these tests are:

• Na = sodium

• Cl = chloride

• K = potassium

• Mg = magnesium

• Glc = glucose (sugar)

• Ca = calcium (bone mineral)

• PO4 = phosphate (bone mineral)

• BUN = blood urea nitrogen (kidney)

• Cr = creatinine (kidney)

• SGOT = serum glutamic oxaloacetic transaminase (liver)

• SGPT = serum glutamic pyruvic transaminase (liver)

• GGT = gamma glutamyl transferase (liver)

• Alk phos = alkaline phosphatase (liver, bone primarily—also gallbadder)

• Fe = iron

• TIBC = total iron binding capacity

• transferrin = iron

• uric acid = checks gout

• chol = cholesterol (fat)

• LDL = low density lipoprotein (“bad” cholesterol)

• HDL = high density lipoprotein (“good” cholesterol)

• TG = triglycerides (fat)

Blood panels may differ from lab to lab. The above tests make up the basic chemistry panel. This should be part of a routine checkup. Some panels may include more tests than those listed above. The urinalysis (UA) may or may not be included, but it is important. Urine tests are able to check for infection, sugar, blood, protein, and many other things. Additional tests that may be ordered by the doctor for preventive screening will depend on your symptoms, diagnosis, family history, and age. Some of these tests are:

• PSA = prostate specific antigen (prostate cancer test)

• TSH = thyroid stimulating hormone (thyroid function)

• T4 = thyroid hormone (thyroid hormone level)

• B12 = vitamin B12

• folate = B vitamin

The Pap smear test and stool for occult blood (blood in stool that cannot be seen with the

naked eye) should also be performed. The Pap smear is a test for females that checks for cancer of the cervix. The stool test, also called Hemoccult test, checks for blood in the stool, which may indicate bleeding from the bowels secondary to cancer, ulcers, or other serious conditions.


Other tests than those listed may be checked depending on your history and physical exam. Be sure you are scheduled for a return visit to follow up on all tests. Some doctors’ offices will also let you know by phone or mail, especially if there is an abnormal test that must be checked before your next appointment.

Your symptoms, the doctor’s physical findings, and blood test results are what the doctor looks at when deciding the next tests that need to be done. This and any additional tests may be used for screening, diagnosis of conditions, and for ongoing management of disease once it is present.