PNH testing guidelines
Although to date there is no standardised methodology for paroxysmal nocturnal haemoglobinuria (PNH) testing, published consensus guidelines offer recommendations on the diagnosis and management of patients with PNH and analytical procedures for routine and high-sensitivity PNH testing.
The first guidelines for the diagnosis and management of PNH were published by the International PNH Interest Group in 2005. This document provides a classification scheme for diagnosing PNH in patients with variable presenting features, clinical manifestations and natural history.
- Parker C et al. Diagnosis and management of paroxysmal nocturnal hemoglobinuria. Blood 2005; 106: 3699-3709.
More recently, specific guidelines on the accurate identification and monitoring of PNH clones using flow cytometry were published by the International Clinical Cytometry Society (ICCS) in 2010. The goal of this document was not to mandate a single approach but rather to provide guidelines regarding best practice in PNH testing based on combined knowledge from technical and clinical experts.
The main criterion for PNH testing reported in these guidelines is the selection of suitable gating antibodies with at least two different antibodies against two or more different surface glycosylphosphatidylinositol (GPI)-linked proteins. Testing should be performed on at least two different cell populations (not lymphocytes) and performed using fresh peripheral blood samples with no signs of degranulation.
- Borowitz MJ et al. Guidelines for the diagnosis and monitoring of paroxysmal nocturnal hemoglobinuria and related disorders by flow cytometry. Cytometry B Clin Cytom 2010; 78B: 211-230.
The ICCS guidelines were followed in 2012 by a supporting document outlining concise, practical protocols for the high-sensitivity detection of PNH clones. These guidelines describe in detail the proper selection of antibody clones and fluorochromes, sample preparation and set-up of protocols, including diagnostic dot plots and control dot plots. Common problems are also highlighted, along with recommendations on instrument optimisation.
- Sutherland DR et al. Practical guidelines for the high-sensitivity detection and monitoring of paroxysmal nocturnal hemoglobinuria clones by flow cytometry. Cytometry B Clin Cytom 2012; 82B: 195-208.