Peptides are molecules that are formed by two or more joined amino acids, and they are believed to play a large role in fundamental biochemical and physiological human functions. Larger sequences are referred to as proteins, and they can appear as hormones, antibiotics, receptors and enzymes. There are two main types of peptide tests: the C-peptide test that measures insulin production and the brain natriuretic peptide test (BNP) that measures the amount of BNP in the blood. Both of these tests measure levels of peptides in the blood to determine if there are health issues such as diabetes or heart disease.
The C-peptide test usually is conducted when a person is at risk for or has just been diagnosed with diabetes, either type 1 and type 2. This type of peptide test measures the level of peptides in the blood to determine how much, or how little, insulin is naturally created in the pancreas. Insulin typically allows the body to make, use and maintain glucose (sugar) in the blood. When the pancreas does not make enough insulin, the person usually has type 1 diabetes, and when it makes too much, the person usually has type 2 diabetes. This form of testing also can identify whether a person has low blood sugar, also known as hypoglycemia, from too much diabetes medicine or a tumor in the pancreas.
The BNP peptide test is used to monitor and check for heart failure and to determine the person’s response to heart failure treatment methods. The BNP chemical in the blood is manufactured by the heart and normally is found at low levels. When a person has heart problems, the heart has to work harder, thus increasing the levels of BNP that are produced. When a doctor conducts the BNP test, he or she can see how overworked the heart is and can propose a treatment plan.
When a person is scheduled for a peptide test, he or she usually is asked to not eat or drink anything but water for eight to 12 hours before the test. For the C-peptide test, most patients are asked to refrain from taking insulin or oral medicines that treat type-2 diabetes beforehand, because the drugs can change the overall test results. The test usually is simple and takes only 10 to 15 minutes. It involves drawing a vial of blood in a clinic or doctor’s office, and it usually is relatively painless, depending on the practitioner and the patient’s sensitivity to needles.
