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Heghine Khachatryan: Diagnosing PNH in Resource-Limited Settings
Apr 12, 2026, 21:24

Heghine Khachatryan: Diagnosing PNH in Resource-Limited Settings

Heghine Khachatryan, Editor-in-Chief of Hemostasis Today, Head of Hemophilia and Thrombosis Center at Yeolyan Hematology and Oncology Center, shared a post on LinkedIn:

“Diagnosing PNH in Resource-Limited Settings

A Suspicion-Driven, Algorithmic Approach for Modern Clinical Practice

Paroxysmal nocturnal hemoglobinuria (PNH) is frequently underdiagnosed – not because it is rare, but because it is insufficiently suspected. In middle – and low-income settings, the diagnostic gap is driven by limited access to high-sensitivity flow cytometry and the protean nature of clinical presentation.

This necessitates a shift from technology-driven diagnosis to suspicion-driven medicine.

Step 1 — Recognize the Clinical Signal

PNH should be actively considered in patients with:

  • Coombs-negative hemolytic anemia
  • Unexplained cytopenias or marrow failure syndromes
  • Aplastic anemia / hypoplastic bone marrow
  • Thrombosis at unusual sites (hepatic, portal, cerebral)
  • Hemoglobinuria or iron deficiency of unclear origin

Clinical pattern recognition remains the most powerful diagnostic tool.

Step 2 — Build the Hemolysis Profile (Accessible Layer)

Even in constrained settings, a structured laboratory panel can establish high suspicion:

  • CBC plus reticulocyte count
  • High LDH
  • High indirect bilirubin
  •  Low Haptoglobin
  • Direct antiglobulin test (negative)
  • Urine hemoglobin / hemosiderin

These findings do not confirm PNH, but define the population requiring definitive testing.

Step 3 — Confirm with High-Sensitivity Flow Cytometry

According to International Society on Thrombosis and Haemostasis and European Hematology Association:

  • Detection of GPI-deficient cells is the diagnostic cornerstone
  • FLAER-based assays are preferred
  • Neutrophil and monocyte clones provide the most reliable estimate of disease burden

RBC-based assays alone may underestimate clone size, particularly in hemolysis or post-transfusion states.

Step 4 — Adapt Strategy to Resource Availability

In low-resource environments, the optimal pathway is:

Suspect early – screen intelligently – refer strategically

  • Prioritize sample referral to regional centers
  • Avoid reliance on low-sensitivity or outdated assays
  • Interpret negative results cautiously if methodology is limited

Why This Matters

Delayed diagnosis directly translates into:

  • Missed prevention of life-threatening thrombosis
  • Prolonged morbidity from untreated hemolysis
  • Failure to identify bone marrow failure overlap syndromes

Key Insight

PNH is not difficult to diagnose.

It is difficult to think of.

In resource – limited settings, diagnostic excellence begins with clinical suspicion, not technology.”

Heghine Khachatryan

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