What are the other Names for this Test? (Equivalent Terms)
- Familial Early-Onset Coronary Heart Disease PCSK9 Blood Test
- Familial Hypercholesterolemia Blood Test
- FH PCSK9 Blood Test
What is PCSK9 Screening Blood Test? (Background Information)
- Proprotein convertase subtilisin/kenexin 9 (PCSK9) is an enzyme involved in regulating cholesterol levels. Genetic mutations can enhance or impede its function, affecting blood cholesterol levels
- Cholesterol is transported throughout the blood using carrier proteins, called lipoproteins. This is necessary, because cholesterol and fats are not soluble in blood, and would otherwise coagulate and clog blood vessels
- Lipoproteins range in composition and their names vary accordingly. For example, very-low density lipoproteins and chylomicrons contain high amounts of fat per protein. High-density lipoproteins contain less fat per protein
- Low-density lipoproteins (LDL) transport fat and cholesterol from the liver to the rest of the body. Thus, they are called “bad” cholesterol
- High-density lipoproteins (HDL) transport fat and cholesterol from the body back to the liver, for metabolism. Thus, they are called “good” cholesterol
- Lipoproteins contain apolipoproteins (“apo-“ meaning detached) as part of their structure. Apolipoproteins are required for transport and migration outside the blood vessel and into cells for metabolism
- The type of apolipoprotein contained by a lipoprotein, determines where the lipoprotein will go. This is because, cells at the blood vessel linings contain receptors that recognize lipoproteins based on the apolipoproteins they contain
- PCSK9 binds to the receptors of blood vessel linings that recognize LDL, the “bad” cholesterol. Once bound, the receptors are inactivated and are unable to import LDL from the blood to metabolize it. This causes a rise in blood LDL levels
- Since, elevated LDL is associated with cardiovascular disease, mutations in PCSK9 that increase its function, may increase the likelihood of this disease. Alternatively, mutations that inhibit PCSK9 function, or drugs that inactivate it, may lead to a decrease in blood LDL levels
- The instructions for producing PCSK9 are encoded on the PCSK9 gene. Mutations in this gene may alter functioning of PCSK9. This may influence blood LDL levels, affecting the likelihood of developing cardiovascular diseases
- The PCSK9 Screening Blood Test is a test to detect the presence of PCSK9 mutations from cells in blood. It is used to determine, if the cause of elevated cholesterol levels are due to a PCSK9 mutation. It is also used to evaluate the risk of familial cardiovascular disease
- Drugs are currently being developed that inhibit PCSK9. These drugs act by lowering circulating cholesterol. Since LDL is a known risk factor for cardiovascular disease, it is possible to make drugs to reduce the risk of developing heart and vascular disorders
What are the Clinical Indications for performing the PCSK9 Screening Blood Test?
Following are the clinical indicators for performing a PCSK9 Screening Blood Test:
- Following-up to a finding of elevated cholesterol levels
- Family history of cardiovascular disease or PCSK9 mutation
- Cholesterol-rich deposits (xanthomas) around the joints or eyelids
- Chest pain or tightness, especially upon exertion
How is the Specimen Collected for PCSK9 Screening Blood Test?
Following is the specimen collection process for PCSK9 Screening Blood Test:
Sample required: Blood
Process: Insertion of a needle into an arm vein.
Preparation required: No special preparation is needed prior to the test.
What is the Significance of the PCSK9 Screening Blood Test Result?
The significance of PCSK9 Screening Blood Test is explained:
- Mutations in PCSK9 may indicate familial hypercholesterolemia
- Further testing is required to assess the familial origin of PCSK9 mutation
- Certain medications may be used, depending on the results of the test
The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.
Additional and Relevant Useful Information:
- PCSK9 Screening Blood Test is a preliminary test to detect PCSK9 mutations. Further DNA sequencing can be performed to evaluate familial PCSK9 mutations
Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider, the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.