Description
Why It’s Done
The PNH (CD55 & CD59) test is performed for several reasons:
• Diagnose PNH: This test is the gold standard for diagnosing PNH. The absence or deficiency of CD55 and CD59 on red blood cells confirms the presence of PNH.
• Assess symptoms of hemolysis: In PNH, red blood cells are destroyed prematurely, which can cause symptoms like fatigue, abdominal pain, dark urine, shortness of breath, and anemia. The test helps confirm whether these symptoms are caused by PNH.
• Evaluate for bone marrow failure: PNH can lead to bone marrow failure, resulting in pancytopenia (a reduction in all blood cell types). This test can be used to investigate unexplained blood count abnormalities.
• Monitor disease progression: For patients with an established diagnosis of PNH, the test is used to monitor disease activity and the effectiveness of treatment, including the risk of complications such as thrombosis (blood clots).
• Differentiate PNH from other causes of hemolytic anemia: Since other conditions can also cause hemolysis, this test helps to distinguish PNH from other types of hemolytic anemia.
Preparation
• No fasting required: Generally, there is no need to fast before the PNH (CD55 & CD59) test.
• Medications: Inform your doctor about any medications you are taking, as certain medications may interfere with test results or influence complement activity (such as immunosuppressive drugs).
• Blood sample: The test requires a blood sample drawn from a vein, typically in the arm. The blood sample will be analyzed using flow cytometry to detect the absence or deficiency of CD55 and CD59 proteins.
• Timing: This test can be performed at any time, but in patients with fluctuating symptoms, it may be most informative during episodes of hemolysis or when symptoms are prominent.
• No special restrictions: There are no special dietary restrictions or other requirements prior to the test, but following your healthcare provider’s instructions is important for the best results.
