Explore Blood Tests
Blood tests show whether the levels of different substances in your blood fall within a normal range.
For many blood substances, the normal range is the range of levels seen in 95 percent of healthy people in a certain group. For many tests, normal ranges vary depending on your age, gender, race, and other factors.
Your blood test results may fall outside the normal range for many reasons. Abnormal results might be a sign of a disorder or disease. Other factors—such as diet, menstrual cycle, physical activity level, alcohol intake, and medicines (both prescription and over the counter)—also can cause abnormal results.
Your doctor should discuss any unusual or abnormal blood test results with you. These results may or may not suggest a health problem.
Many diseases and medical problems can't be diagnosed with blood tests alone. However, blood tests can help you and your doctor learn more about your health. Blood tests also can help find potential problems early, when treatments or lifestyle changes may work best.
This section presents the result ranges for some of the most common blood tests.
NOTE: All values in this section are for adults only. They don't apply to children. Talk to your child's doctor about values on blood tests for children.
The table below shows some normal ranges for different parts of the complete blood count (CBC) test. Some of the normal ranges differ between men and women. Other factors, such as age and race, also may affect normal ranges.
Your doctor should discuss your results with you. He or she will advise you further if your results are outside the normal range for your group.
|Test||Normal Range Results*|
|Red blood cell (varies with altitude)||Male: 5 to 6 million cells/mcL|
Female: 4 to 5 million cells/mcL
|White blood cell||4,500 to 10,000 cells/mcL|
|Platelets||140,000 to 450,000 cells/mcL|
|Hemoglobin (varies with altitude)||Male: 14 to 17 gm/dL |
Female: 12 to 15 gm/dL
|Hematocrit (varies with altitude)||Male: 41% to 50%|
Female: 36% to 44%
|Mean corpuscular volume||80 to 95 femtoliter†|
This table shows the ranges for blood glucose levels after 8 to 12 hours of fasting (not eating). It shows the normal range and the abnormal ranges that are a sign of prediabetes or diabetes.
|Plasma Glucose Results (mg/dL)*||Diagnosis|
|70 to 99||Normal|
|100 to 125||Prediabetes|
|126 and above||Diabetes†|
The table below shows ranges for total cholesterol, LDL ("bad") cholesterol, and HDL ("good") cholesterol levels after 9 to 12 hours of fasting. High blood cholesterol is a risk factor for coronary heart disease.
Your doctor should discuss your results with you. He or she will advise you further if your results are outside the desirable range.
|Total Cholesterol Level||Total Cholesterol Category|
|Less than 200 mg/dL||Desirable|
|200–239 mg/dL||Borderline high|
|240 mg/dL and above||High|
|LDL Cholesterol Level||LDL Cholesterol Category|
|Less than 100 mg/dL||Optimal|
|100–129 mg/dL||Near optimal/above optimal|
|130–159 mg/dL||Borderline high|
|190 mg/dL and above||Very high|
|HDL Cholesterol Level||HDL Cholesterol Category|
|Less than 40 mg/dL||A major risk factor for heart disease|
|40–59 mg/dL||The higher, the better|
|60 mg/dL and above||Considered protective against heart disease|
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The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.