Flow cytometry is a sensitive and informative tool in PNH diagnosis and monitoring 1,2

ICCS guidelines recommend routine (1% PNH cell threshold) or high-sensitivity (0.01% PNH cell threshold) flow cytometry for patients at high risk of PNH 1

Early diagnosis is essential for improved patient management and prognosis 3,4



IDENTIFY PATIENTS WITH PNH EARLY WITHIN HIGH-RISK GROUPS1,2,5-14




IDA = iron deficiency anaemia; MDS = myelodysplastic syndrome. *Anaemia, neutropenia, thrombocytopenia, or pancytopenia. †Unusual sites include hepatic veins (Budd-Chiari syndrome), other intra-abdominal veins (portal, splenic, splanchnic), cerebral sinuses, and dermal veins. ‡Detects PNH cells down to at least 0.01 clone size.

Download the pdf version of the Diagnostic Pathway

RBC analysis alone is not enough 1,2

Evaluation of RBCs alone may under-report clone size due to haemolysis and the dilution effect of transfusions 1-2,15,17

Granulocytes give the most accurate estimate of PNH lone size 1,2,11

Analysis of granulocytes and RBCs in a patient with PNH 1

PNH granulocyte clone: 55%


Adapted from Borowitz et al, 2010

PNH RBC clone: 6%



  • FLAER/CD24 combinations are recommended to detect PNH granulocytes 15
  • Low RBC clone size compared to WBC clone size is indicative of intravascular haemolysis 1

Ongoing Monitoring of PNH Clone Size is Important 1,2,16

  • Regular monitoring of patients with a previously identified PNH clone, is important 1,2
  • PNH clones can expand at any time 1,2


Adapted from Movalia et al, 2011



Study design: High sensitivity flow cytometry, with sensitivity up to 0.01%, was used to analyse 6,897 patients who were screened for PNH clones. The study included an examination of the change in PNH clone sizes among patients who had follow-up studies in 3–12 months.

Annual monitoring should be considered even for patients with a PNH clone size of < 0.1%.
For patients with a PNH clone size of > 1%, monitoring at least semi-annually is recommended.16

Find out more

    PNH = Paroxysmal Nocturnal Haemoglobinuria


  • References:
  • 1. Borowitz MJ, et al; for Clinical Cytometry Society.
    Cytometry Part B. 2010;78B:211-230.
  • 2. Parker C, et al. for International PNH Interest Group.
    Blood. 2005;106:3699-3709.
  • 3. Richards SJ, Barnett D. Clin Lab Med. 2007;27:577-590
  • 4. Socie G et al.Lancet 1996;348:573-577
  • 5. Rachidi S, et al. Eur J Intern Med. 2010;21:260-267.
  • 6. Hillmen P, et al. Am J Hematol. 2010;85:553-559.
  • 7. Brodsky RA. In: HoffmanR, Benz EJJr, Shattil SJ, et al,
    eds. Hematology: Basic Principles and Practice. 4th ed.
    Philadelphia, PA:Elsevier Churchill Livingstone; 2005:419-
    427.
  • 8. Dolezel Z, et al. Pediatr Nephrol. 2004;19:1177-1179.1
  • 9. Ballarín J, et al. Nephrol Dial Transplant. 2011;26:3408-
    3411.
  • 10. Sharma VR. Clin Adv HematolOncol. 2013;11:1-11.
  • 11. Brodsky RA. Blood. 2009;113:6522-6527.
  • 12. Mohanty BD, De Castro CM.Am J Med. 2012;125:243-245.
  • 13. Meyers G, Parker CJ. Int J Hematol. 2003;77:125-132. 23.
  • 14. Brodsky A, et al. Exp Hematol Oncol. 2012;1:26.
  • 15. Sutherland R, et al. Am J Clin Pathol 2009;132:564-572
  • 16. Movalia K, et al. Blood 2011 118:1033.
  • 17. Hochsmann B, et al. Ann Hematol. 2011;90:887-899.
  • 18. Sutherland DR, et al. Cytometry Part B. 2012;82B:195-208.

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