American Medical Association Family Medical Guide - American Medical Association [110]
Hemoglobin
The hemoglobin test measures the amount of hemoglobin (the oxygen-carrying pigment that gives blood its red color). The hemoglobin test is also used to determine if levels of red blood cells are normal. A low level of hemoglobin indicates iron deficiency anemia.
Platelet count
The platelet count measures the amount of platelets (cell fragments that enable blood to clot) in the blood. It is important to know the number of platelets if you are going to have surgery. Low platelet counts can result from leukemia and other cancers or from treatment for cancer. High platelet counts can result from bone marrow diseases or iron deficiency anemia. Very low platelet counts can be a sign of internal bleeding.
Blood Chemistry Tests
A blood chemistry profile consists of a number of tests that measure the levels of certain chemical substances in blood serum (the liquid part of the blood). Abnormal blood chemistry test results may, but not always, indicate a health problem, and normal test results can occur in people who have a medical disorder. If you have an abnormal test result, your doctor will order another blood test to see if the results are consistent before recommending further medical tests. The ranges given for normal results can vary slightly from laboratory to laboratory.
Measuring Cholesterol Levels
Beginning at age 20, you should have a cholesterol test at least every 5 years, and more frequently if you have a family history of heart disease. The numbers provided on your cholesterol profile can help your doctor evaluate your risk of developing heart disease. Your risk of heart disease is low if your total cholesterol level is less than 200 milligrams per deciliter (mg/dL), your LDL (bad) cholesterol level is below 100 mg/dL, your HDL (good) cholesterol level is 60 mg/dL or higher, and your triglyceride level is less than 150 mg/dL. The measurement is most reliable when performed after you have fasted for 12 hours.
Total Cholesterol Level of Risk for Heart Disease
Less than 200 mg/dL Low
200-239 mg/dL Borderline high
240 mg/dL and above High
LDL Cholesterol
Less than 100 mg/dL Low
100-129 mg/dL Moderately low
130-159 mg/dL Borderline high
160-189 mg/dL High
190 mg/dL and above Very high
HDL Cholesterol
60 mg/dL and above Low
50-59 mg/dL Moderately low
40-49 mg/dL Borderline high
39 mg/dL or less High
Triglycerides
Less than 150 mg/dL Low
151-199 mg/dL Borderline high
200-499 mg/dL High
500 mg/dL and above Very high
Cholesterol and lipids
A cholesterol and lipids test measures the levels of various fats in the blood, including triglycerides; HDL (high-density lipoprotein), the good cholesterol; and LDL (low-density lipoprotein), the bad cholesterol. Increased levels of triglycerides or LDL cholesterol and decreased levels of HDL cholesterol can indicate an increased risk of cardiovascular disease, including heart disease, atherosclerosis, and stroke. Doctors use the cholesterol test to evaluate heart disease risk. Drugs such as corticosteroids, thiazide diuretics, and oral contraceptives can affect cholesterol levels. Excess alcohol intake, kidney and liver diseases, obesity, menopause, diabetes, and hypothyroidism (an underactive thyroid gland) also can affect cholesterol and lipid levels.
Glucose
Glucose is a sugar that the body uses for energy. The hormone insulin, which is produced by the pancreas, regulates the level of glucose in the blood. Increased levels of glucose can be a sign of diabetes. Decreased levels of glucose can be a sign of adrenal insufficiency (underfunctioning of the adrenal glands). Conditions such as a stroke or heart attack can temporarily increase glucose levels. Medications such as corticosteroids, diuretics, and tricyclic antidepressants also can increase glucose levels. In general, low blood glucose is a rare condition in people who are otherwise healthy. The normal glucose range is 65 to 109 milligrams per deciliter (mg/dL).
Albumin
The albumin test measures the amount in the blood of the