POLYCYTHEMIA (ERYTHROCYTOSIS)
Polycythemia is an increase above the normal range of RBCs in the circulation. Concern that the Hb level may be abnormally high should be triggered at a level of 170 g/L (17 g/dL) in men and 150 g/L (15 g/dL) in women. Polycythemia is usually found incidentally at routine blood count. Relative erythrocytosis, due to plasma volume loss (e.g., severe dehydration, burns), does not represent a true increase in total RBC mass. Absolute erythrocytosis is a true increase in total RBC mass.
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Citation
Kasper, Dennis L., et al., editors. "POLYCYTHEMIA (ERYTHROCYTOSIS)." Harrison's Manual of Medicine Harrison's Manual of Medicine, 20th ed., McGraw Hill Inc., 2020. Harrison's Manual of Medicine, harrisons.unboundmedicine.com/harrisons/view/Harrisons-Manual-of-Medicine/623564/all/POLYCYTHEMIA__ERYTHROCYTOSIS_.
POLYCYTHEMIA (ERYTHROCYTOSIS). In: Kasper DLD, Fauci ASA, Hauser SLS, et al, eds. Harrison's Manual of Medicine Harrison's Manual of Medicine. McGraw Hill Inc.; 2020. https://harrisons.unboundmedicine.com/harrisons/view/Harrisons-Manual-of-Medicine/623564/all/POLYCYTHEMIA__ERYTHROCYTOSIS_. Accessed October 5, 2026.
POLYCYTHEMIA (ERYTHROCYTOSIS). (2020). In Kasper, D. L., Fauci, A. S., Hauser, S. L., Longo, D. L., Jameson, J. L., & Loscalzo, J. (Eds.), Harrison's Manual of Medicine Harrison's Manual of Medicine (20th ed.). McGraw Hill Inc.. https://harrisons.unboundmedicine.com/harrisons/view/Harrisons-Manual-of-Medicine/623564/all/POLYCYTHEMIA__ERYTHROCYTOSIS_
POLYCYTHEMIA (ERYTHROCYTOSIS) [Internet]. In: Kasper DLD, Fauci ASA, Hauser SLS, et al, eds. Harrison's Manual of Medicine Harrison's Manual of Medicine. McGraw Hill Inc.; 2020. [cited 2026 October 05]. Available from: https://harrisons.unboundmedicine.com/harrisons/view/Harrisons-Manual-of-Medicine/623564/all/POLYCYTHEMIA__ERYTHROCYTOSIS_.
* Article titles in AMA citation format should be in sentence-case
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T1 - POLYCYTHEMIA (ERYTHROCYTOSIS)
ID - 623564
ED - Jameson,J Larry,
ED - Loscalzo,Joseph,
ED - Kasper,Dennis L,
ED - Fauci,Anthony S,
ED - Hauser,Stephen L,
ED - Longo,Dan L,
BT - Harrison's Manual of Medicine
UR - https://harrisons.unboundmedicine.com/harrisons/view/Harrisons-Manual-of-Medicine/623564/all/POLYCYTHEMIA__ERYTHROCYTOSIS_
PB - McGraw Hill Inc.
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DB - Harrison's Manual of Medicine
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Harrison's Manual of Medicine

