Blood tests are used for several reasons including to diagnose a condition, to rule out certain diseases, to monitor an already diagnosed condition, to monitor a treatment plan, or to check your overall general health. With all these reasons in mind, it is likely at some point in life you will require a blood test.
However, the results can be confusing, even when a doctor is explaining them to you. Test results are not always negative or positive, they may be borderline, inconclusive, numerical, reactive, non-reactive, and even your gender may affect the result. An abnormal result does not always mean you are unwell, just as a normal result does not always mean you are healthy. Blood test results can be perplexing, to say the least.
For this reason, this simple guide will give you a basic understanding of some of the more common tests. Having a basic understanding of blood test results will allow you to feel more confident and in control of understanding your medical care.
Don't see your test listed below? Check out our other detailed guides on how to read your various lab results!
How to Read Your Wellness Lab Results
How to Read Your STD Lab Results
How to Read Your Hormone Test Results
What do my results mean?
With hundreds of types of laboratory tests, it is impossible to cover them all. Therefore this section will focus on the basics and most common blood tests.
Common abbreviations
Abbreviation |
Meaning |
cmm |
Cells per cubic milliliter |
fL (femtoliter) |
Fraction of one-millionth of a liter |
g/dL |
Grams per deciliter |
IU/L |
International units per liter |
mEq/L |
Milliequivalent per liter |
mg/dL |
Milligrams per deciliter |
mL |
Milliliter |
mmol/L |
Millimoles per liter |
ng/mL |
Nanograms per milliliter |
pg |
One-trillionth of a gram |
mcL |
Microliter |
What is a reference range?
When looking at your lab results you may see something called a reference range, which is also known as normal values. This range of normal values is determined by examining the normal test results of a large group of healthy people. It shows the range within which most typical people's test results will sit.
It is important to remember that not everyone is 'typical'. Your results may fall within the normal range but you could still be experiencing symptoms. Or, you may be completely healthy and your results fall outside of the reference range. In both of these scenarios, you will need further investigations.
False positives and negatives.
Although rare, it is possible to test positive for a condition you don't have or test negative for a condition you do have. There are lots of reasons that this may happen including the test not being carried out correctly, being carried out at the wrong time, or problems with the equipment. Although it is not common, it is important to understand that it can happen.
Components of common blood test results and how to interpret them
CBC (Complete Blood Count)
A CBC measures the volume of blood cells that make up your blood. It identifies if the body is making the right number of each type of cell, and it can highlight issues such as infection, bleeding, certain diseases, or clotting problems. There are several different sub-tests within a CBC and here are a few of the most important ones:
Test name |
Overview |
Reference range |
White blood cell count (WBC) |
White blood cells, also known as leukocytes, help you to fight infection. A high white cell count may indicate that there is an infection present or possibly a disease like leukemia. A low white blood cell count can indicate conditions such as autoimmune diseases. |
WBC per microliter of blood (mcL):
|
Differential white blood cell count |
White blood cells are made up of five different components. This test measures the volume, shape, and size of these different components. If they are out of balance, it identifies that there may be an infection or medical condition present. |
Neutrophils |
Red blood cell count (RBC) |
Red blood cells, also known as erythrocytes, carry oxygen through the body. This test checks the volume of red blood cells in the body. If the results are above or below the reference range, it can indicate that a medical condition is present. However, further tests would be needed to determine the problem. |
|
Hematocrit test (Hct) |
Determines how much of the total blood volume in the body consists of red blood cells and is useful for diagnosing anemia. |
|
Hemoglobin test (Hgb) |
Hemoglobin is what delivers oxygen from the lungs to the body and makes your blood red. Low hemoglobin levels can indicate anemia. |
Men 14-18 g/dL. |
Platelet count |
Platelets are involved in clotting and too many, or too few platelets, can affect how your blood clots. |
Comprehensive Metabolic Panel (also known as chemistry panel)
A comprehensive metabolic panel measures glucose levels, fluid and electrolyte balance, liver function, and kidney function. There are several different sub-tests within this panel and here are a few of the most important ones:
Test name |
Overview |
Reference range |
Total protein test |
Also known as albumin/globulin ratio or A/G ratio. Albumin and globulin are the two types of protein found in your blood and raised levels can indicate inflammation, infection, or a bone marrow disorder. Low levels can indicate malnutrition, a kidney problem, or a liver problem. |
A/G ratio is normally slightly higher than 1. |
Glucose test |
This measures the amount of Glucose in your blood. This testing is typically done for those with Diabetes. |
Normal: 140 mg/dL or lower |
ALT Test |
Alanine Aminotransferase Test (ALT) is used to diagnose Liver disorders. ALT is a liver enzyme that is released into the bloodstream when liver cells have been damaged. |
Men: Women: |
AST |
Aspartate Aminotransferase (AST), also known as SGOT, is used to measure the amount of this enzyme in the blood. |
5-40 IU/L |
Alkaline phosphatase test |
This is an enzyme produced in both liver and bone cells. Therefore, results outside of the reference range can indicate bone or liver problems. |
44 to 147 IU/L |
Calcium test |
Measures the level of calcium in the blood. Low levels may indicate cancer, tuberculosis, and other problems. High levels may be due to problems like rickets or malnutrition. |
8.5 to 10.5 mg/dL (lower in the elderly) |
Creatinine test |
Creatinine is a waste product produced by the kidneys, therefore levels outside of the reference range may indicate a kidney problem. |
Men: Women: |
Phosphorus test |
Phosphorus is related to calcium and bone health. High levels can indicate a problem with your kidneys or the parathyroid gland. |
3.4-4.5 mg/dL |
Sodium test |
Sodium is a mineral that helps your body balance water levels and helps with nerve impulses and muscle contractions. Levels outside of the reference range can be for several reasons such as dehydration, high salt intake, levels of medications, kidney problems, or liver problems. |
135 to 145 mEq/L |
Lipid Panel
This measures the different types of triglycerides and cholesterol (fats) in the blood. Common sub-tests within a lipid panel include:
Test name |
Overview |
Reference range |
Total Cholesterol Test |
Measures the total level of cholesterol in your blood (good- HDL and bad LDL). |
Healthy Borderline high: High: |
Triglycerides test |
Triglycerides are a type of fat found in the blood that link to both heart disease and diabetes. |
Normal: less than 150 mg/dL |
HDL cholesterol test |
Good cholesterol |
Optimal: Above 60 mg/dL Good: 50 to 60 mg/dL Poor: Below 40 mg/dL for men and below 50 mg/dL for women. |
LDL cholesterol test |
Bad cholesterol |
Optimal: Less than 100 mg/dL |
These are just some of the more common lab tests that you may encounter. Understanding your test results is essential in being proactive with your health. It can give you a better understanding when your doctor is talking through your results. However, if you are ever confused about your test results, or do not fully understand them, then reach out to your doctor for advice. It is ok to ask questions. Private MD Labs is here to provide confidential laboratory testing to individuals who take charge of their own health. You can order your lab tests online through our website or call us at (877) 283-7882 for further information.
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