P-Anca Blood Test Results Fully Explained


The P-ANCA blood test is used to determine if there is the presence of perinuclear anti-neutrophil cytoplasmic antibodies present within the blood. This simple test uses a stain to determine their presence because the antibodies offer a positive charge at a pH of 7. These antibodies will form against certain antigens, but one in particular, MPO [myeloperoxidase] is usually the primary target.

The test results from the P-ANCA blood test will either be positive or negative. A negative result means that these antibodies are not present within the blood. A positive result can indicate one of a number of medical conditions that may be causing bothersome physical symptoms. The most common reason for a medical provider to order the P-ANCA blood test is to determine the presence of ulcerative colitis.

The P-ANCA Blood Test Is Positive With These Additional Conditions

The P-ANCA blood test may be the most specific for ulcerative colitis, but it cannot be used on its own to create a diagnosis. This is because it isn’t sensitive enough to be able to be a fully reliable test. The specificity rate of this test is above 95% for this condition, but the sensitivity rate is below 50%. For this reason, the P-ANCA test is usually ordered with a series of other blood tests so that a diagnosis can be given after comparing all results.

Rheumatoid arthritis, glomerulonephritis, and polyarteritis nodosa are also conditions that the P-ANCA blood test may be able to detect. Churg-Strauss syndrome is also indicated by this blood test in about half of all cases. Certain cases of hepatitis, systemic lupus, and specific heart infections have also been known to create a positive test result.

Inflammatory bowel disease may also be present and detected by this blood test. Specific equipment is necessary for the test results to be received, so not every medical provider will be capable of running this test after a blood draw. For this reason, test results may take 3-5 days to receive.

When Is the Test Ordered?

The problem with most of the conditions that can be detected by the P-ANCA blood test is that they offer non-specific and very vague symptoms when they first begin. Someone may be experiencing joint aches, night sweats, and an increase level of fatigue. Muscle aches, a fever, or weight loss may also be included.

There may also be some co-occurring symptoms that may lead a medical provider to believe a different problem is forming. Those who may need the P-ANCA blood test may suffer from the symptoms of pink eye, experience hearing loss, or have hay fever symptoms that do not go away or respond to treatment. Rashes may form in the skin, protein might be found in the urine, and they may be having difficulties in breathing.

For those who may be suffering from an inflammatory bowel disease issue, there may be abdominal cramping, bright red blood found on the toilet tissue, and consistent diarrhea. For children, it is important to schedule an appointment immediately if these signs or symptoms are present because continued symptoms may lead to delays in growth and learning.

How Is a Positive Test Indicated?

When the P-ANCA blood test is given to the laboratory, the sample will be tested to determine the presence of antibodies. Due to the amount of fluorescence involved, a positive or negative test result may be determined. It is possible for fluorescence to be present in low-level quantities and the test result still be negative.

The antibodies can also change in their quantity over time depending on the disease that is causing the bothersome symptoms. If there is more fluorescence present, then the antibody levels are generally in a higher amount. This allows the P-ANCA blood test to be used for tracking purposes in addition to the initial testing.

The antibodies, once presence, will never go away. For this reason, a medical provider may wish to take a tissue biopsy of the suspected area that has been affected to confirm the presence of an autoimmune disorder.

Although the levels of antibodies fluctuate and never go away, it is possible to treat the bothersome symptoms and potentially reduce an autoimmune response when it occurs. If there are symptoms that are not going away despite lifestyle changes and home treatment methods, then it is important to schedule an appointment with a medical provider. The P-ANCA blood test can point doctors in the right direction regarding personal health so that an appropriate treatment plan can be developed and implemented.