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WHO criteria inadequate for diagnosis of early-stage polycythemia vera
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Current WHO criteria for polycythemia vera diagnosis via surrogate markers were found to be inadequate for evaluating red cell volume for early cases, according to study results.
Researchers determined about two-thirds of patients would not have been diagnosed with polycythemia vera using hemoglobin values, and more than one-quarter of patients would not have been diagnosed using hematocrit values.
The 2007 WHO criteria for the diagnosis of polycythemia vera included two major criteria:
- Hemoglobin >18.5 g/dL in men, 16.5 g/dL in women or other evidence of increased red cell volume; and
- The presence of JAK2 V617F or other functionally similar mutation, such as JAK2exon 12 mutation.
However, recent studies show that, in clinical practice, testing is most often completed using only hemoglobin values for estimating red cell volume.
Richard T. Silver
Richard T. Silver, MD, of the division of hematology and medical oncology at Weill Cornell Medical College in New York, and colleagues followed 30 patients with myeloproliferative neoplasms for 5 years to assess the accuracy of the 2007 WHO criteria for diagnosing polycythemia vera, particularly in early-stage patients.
At the conclusion of the study, 28 of 30 patients were diagnosed with polycythemia vera due to an elevated Cr-51 red cell mass, JAK2 positivity and at least one minor WHO criterion. However, 18 patients with polycythemia vera did not meet WHO criterion for an increased hemoglobin value, and an additional eight did not meet WHO criterion for an increased hematocrit value.
Among the 28 patients with an elevated red cell mass, 10 (35.7%) met WHO criterion for an increased hemoglobin value, 20 (71.4%) met WHO criterion for an increased hematocrit value, and 20 (71.4%) met WHO criterion for either an increased hemoglobin or hematocrit value.
“We recommend revision of the WHO criteria for the diagnosis of polycythemia vera patients, especially those with early-stage disease,” Silver and colleagues wrote. “Our data indicate the hazard of using consensus criteria based on expert opinions and not validated by fact. Major criteria should remain JAK2 positivity and an increased red cell volume. However, for patients with lesser values, only a Cr-51 red cell mass determination will unequivocally demonstrate an increased red cell volume.”
Disclosure: The researchers report no relevant financial disclosures.
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