Most frequently, an elevated packed cell volume (PCV) value arouses the suspicion of a polycythaemic state. The aim of the present work was to assess a few readily available variables which could help the clinician to differentiate between polycythaemia vera (PV) and apparent polycythaemia (AP). During a 5-year period, 31 consecutive newly diagnosed patients with PV were identified, and during a 4-year period 38 consecutive subjects were considered to be afflicted with AP. In each subject: (i) the red cell mass (RCM) and plasma volume were measured, (ii) the spleen size was assessed using γ-camera imaging, and (iii) the plasma erythropoietin (EPO) concentration was determined. The diagnosis of PV was based upon recently proposed criteria. By definition, all PV patients had absolute erythrocytosis, i.e. the RCM was greater than 25% above the mean normal predicted value for the individual. There was no statistical difference between the plasma volumes for PV and AP patients. However, the mean measured/predicted plasma volume for subjects with AP was significantly lower than the mean for PV. The means for spleen scan areas (posterior and left lateral projections) for AP patients were identical to the mean reference values for our laboratory. As compared to AP, in PV the spleen scan areas were significantly increased, and the lateral spleen scan area was significantly larger than the posterior area. It was also shown that, in contrast to AP, both spleen scan areas were significantly larger in male than in female PV patients. All PV patients had plasma EPO concentrations below the lower reference limit, and in 68% of the patients undetectable EPO concentrations were present. Most AP patients (84%) had EPO values within the reference range; 8% had slightly subnormal, but not undetectable, plasma EPO levels.

Keywords:
Polycythaemia vera, Apparent polycythaemia, Red cell mass, Plasma volume, Spleen size, Plasma erythropoietin
1.
Messinezy M, Pearson TC: Apparent polycythaemia: Diagnosis, pathogenesis and management. Eur J Haematol 1993;51:125–131.
2.
Pearson TC, Botterill CA, Glass UH, Wetherly-Mein G: Interpretation of measured red cell mass and plasma volume in males with elevated venous PCV values. Scand J Haematol 1984;33:68–74.
3.
Brown SM, Gilbert H, Krauss S, Wasserman LR: Spurious (relative) polycythemia: A nonexistent disease. Am J Med 1971;50:200–207.
4.
Berk PD, Goldberg JD, Donovan PB, Fruchtman SM, Berlin NI, Wasserman LR: Therapeutic recommendations in polycythemia vera based on Polycythemia Vera Study Group protocols. Semin Hematol 1986;23:132–143.
5.
Pearson TC, Guthrie DL, Simpson J, Chinn S, Barosi G, Ferrant A, Lewis SM, Najean Y: Interpretation of measured red cell mass and plasma volume in adults: Expert Panel of Radionuclides of the International Council for Standardization in Haematology. Br J Haematol 1995;89:748–756.
6.
Pearson TC, Messinezy M: The diagnostic criteria of polycythaemia rubra vera. Leuk Lymphoma 1996;22(suppl 1):87–93.
7.
Carneskog J, Safai-Kutti S, Suurküla M, Wadenvik H, Bake B, Lindstedt G, Kutti J: The red cell mass, plasma erythropoietin and spleen size in apparent polycythaemia. Eur J Haematol 1999;62:43–48.
8.
Westin J, Lanner L-O, Larsson A, Weinfeld A: Spleen size in polycythemia. A clinical and scintigraphic study. Acta Med Scand 1972;191:263–271.
9.
International Committee for Standardization in Haematology: Recommended methods for measurement of red-cell and plasma volume. J Nucl Med 1980;21:793–800.
10.
Carneskog J, Wadenvik H, Fjälling M, Kutti J: Assessment of spleen size using gamma camera scintigraphy in newly diagnosed patients with essential thrombocythaemia and polycythaemia vera. Eur J Haematol 1996;56:158–162.
11.
Kutti J, Ridell B, Weinfeld A, Westin J: The relation of thrombokinetics to bone marrow megakaryocytes and to the size of the spleen in polycythaemia vera. Scand J Haematol 1973;10:88–95.
12.
Ridell B, Kutti J, Revesz P, Bergström S, Enerbäck L: DNA content and nuclear size of megakaryocytes in thrombocythaemia. APMIS 1990;98:845–850.
13.
Bilgrami S, Greenberg BR: Polycythemia rubra vera. Semin Oncol 1995;22:307–326.
14.
Cotes PM, Doré CJ, Liu Yin JA, Lewis SM, Messinezy M, Pearson TC, Reid C: Determination of serum immunoreactive erythropoietin in the investigation of erythrocytosis. N Engl J Med 1986;315:283–287.
15.
Erslev AJ, Caro J: Pure erythrocytosis classified according to erythropoietin titres. Am J Med 1984;76:57–61.
16.
Zaroulis CG,Hoffman BJ, Kourides IA: Serum concentrations of erythropoietin measured by radioimmunoassay in hematologic disorders and chronic renal failure. Am J Hematol 1981;11:95–103.
17.
Birgegård G, Wide L: Serum erythropoietin in the diagnosis of polycythaemia and after phlebotomy treatment. Br J Haematol 1992;81:603–606.
18.
Carneskog J, Kutti J, Wadenvik H, Lundberg P-A, Lindstedt G: Plasma erythropoietin by high-detectability immunoradiometric assay in untreated and treated patients with polycythaemia vera and essential thrombocythaemia. Eur J Haematol 1998;60:278–282.
19.
Messinezy M, Westwood NB, Woodcock SP, Strong RM, Pearson TC: Low serum erythropoietin – A strong diagnostic criterion of primary polycythaemia even at normal haemoglobin levels. Clin Lab Haematol 1995;17:217–220.
© 2002 S. Karger AG, Basel
2002
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.