The complete blood count [CBC] and comprehensive metabolic panel [CMP] are used as broad screening tools to determine the health of an individual. They are often used as a first-line test to determine if there is something wrong with a patient. These tests are able to evaluate organ function, present an overall glimpse of systemic health, and check for kidney disease, diabetes, or liver disease. The CMP specifically may be ordered to track a known condition, such as hypertension, or to monitor liver or kidney disease treatments.
When Will a Doctor Order the CBC and CMP?
This combined blood test is often ordered as part of a comprehensive yearly exam. The individual tests are usually sensitive enough to determine that there is something that is affecting a person’s health, but they are not often strong enough to provide a specific diagnosis. If the CBC and CMP blood test has abnormal results, then another group of specific tests will typically be ordered to narrow down a suspected diagnosis.
It is not uncommon for some patients, especially those who have been hospitalized, to receive several CBC and CMP blood tests over the course of a few days so that results can be accurately monitored. This information also gives providers the chance to better determine what the health of a patient happens to be.
What Do the Test Results Mean?
Medical providers will take the CBC and CMP test results and look for patterns within the information provided. Having just one abnormal test result often means something different than having several abnormal test results. A high liver enzyme, for example, may be a medically insignificant result. If several enzyme tests come back as abnormal, however, a patient’s medical provider will likely order follow-up testing to determine what is actually wrong with the liver.
If the results of the CBC and CMP blood test are abnormal or “out of range,” then there may be a variety of different conditions causing the issue. Some of the most common problems that are first detected by this combined blood test include the following diseases or health conditions.
Diabetes Mellitus: This includes pre-diabetic conditions that may be present.
Kidney Failure: This also includes an evaluation of electrolyte levels that may affect a person’s acid and base balance.
COPD: Any other conditions that cause breathing problems may also be reflected in the results that this blood test produces.
Many different medications, vitamin combinations, and supplements may alter the results of the CBC and CMP blood test. It is very important to notify your medical provider of any over-the-counter medications, herbal supplements, and other regular treatment items before the test so that the results can be correctly interpreted.
Fasting for up to 12 hours may be required before the blood draw to make sure the test results are accurate.
What If Test Results Are Just Slightly Out of Range?
A common question that people have with the CBC and CMP blood test is that one or two of their test results were slightly out of range and they’re wondering if they could have a serious illness or disease. There are two factors that must be considered by the medical provider when interpreting test results: biological variability and individual variability.
What does this mean? People who are given the CBC and CMP blood test will generally produce different results on different days. The actual numbers will vary daily and sometimes even change on the same day. Even the healthiest of people will typically have at least one or two abnormal results at some point in time.
Individual variability means that what is normal for one person may not be normal for someone else. Medical providers and laboratories use a “range” to interpret results based on information that has been collected over time from a variety of patients. Sometimes people fall into what is called the “standard deviation” and their test results are considered normal even though they fall into abnormal categories for the rest of the general population.
If a test result is slightly abnormal, a medical provider may request additional testing if this is the first time such a result has occurred. If the result is consistent over a series of tests, then the out-of-range result may just be considered normal for the individual.
Although the CBC and CMP blood test is just one draw, more than a dozen overall tests will be run by the laboratory. Most results will come back as normal or within a standard deviation. Use this guide to discuss your specific results with your medical provider so that you’ll have a better picture of what your health is at this moment.