CD59-Deficient Cells in Peripheral Blood
This test measures the proportion of red blood cells and white blood cells that lack the protective protein CD59. A deficiency of CD59 is a hallmark of paroxysmal nocturnal hemoglobinuria (PNH), a rare acquired blood disorder.
["A low percentage of CD59-expressing cells suggests a PNH clone is present and warrants specialist evaluation."]
Key facts at a glance
- LOINC
- 33663-6
- Short code
- CD59
- Synonyms
- CD59 Deficient Cells NFr Bld
- Category
- chemistry
- Sample
- whole-blood
- Container
- EDTA (lavender-top) tube; Sodium heparin (green-top) tube acceptable
- Units
- N/A
- Ref low
- 0
- Ref high
- 5
- Critical range
- — – 10 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Flow cytometry
- CPT
- 88184
- SNOMED
- 395124008
- Specimen volume
- 3-5 mL whole blood
- Stability
- Ambient: 24-48 hours; Refrigerated (2-8°C): up to 72 hours; Do not freeze
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 24–72 hours
- Order
- routine
What This Test Measures
CD59 is a protein normally present on the surface of healthy blood cells. It protects cells from damage by the body's complement system. When a gene mutation causes cells to lack CD59, those cells become "CD59-deficient" and are more vulnerable to destruction. This test uses flow cytometry to count how many peripheral blood cells lack CD59.
Why Your Doctor Ordered It
Your doctor may have ordered this test because of signs of hemolysis (red blood cell breakdown), such as low red blood cell counts, dark urine, unexplained fatigue, or blood clots. The test helps determine whether a population of abnormal, CD59-deficient cells is present, which is characteristic of PNH.
How the Sample Is Collected
A routine blood sample is drawn from a vein, typically in your arm. The sample is sent to a specialized laboratory where it is processed and analyzed by flow cytometry to measure the percentage of cells missing CD59.
What the Results Mean
Results are reported as the percentage of CD59-deficient cells among the red and white blood cells studied. A clearly increased population of deficient cells supports a diagnosis of PNH. Small or borderline populations may require repeat or additional testing. Your doctor interprets results alongside your symptoms and other blood tests. Reference ranges vary by laboratory and should be discussed with your care team.
Reference range
Normal: <5% CD59-deficient red blood cells; Values above reference range may indicate Paroxysmal Nocturnal Hemoglobinuria (PNH) or related disorderN/A
No special preparation required. Specimen should be collected prior to blood transfusion if possible, as transfusion may dilute the abnormal clone.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Paroxysmal Nocturnal Hemoglobinuria (PNH) Cell Analysis
Frequently asked questions
What is CD59?
Does a deficiency of CD59 always mean I have PNH?
Is this test the same as flow cytometry for PNH?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy