Mayo Test Catalog, (Sorted By Test Name) - Mayo Medical ...

FERY
80144
EPO
80173
with lifelong sustained increased RBC mass, elevated RBC count, hemoglobin, or hematocrit
Interpretation: The evaluation includes testing for a hemoglobinopathy and oxygen (O2) affinity of
the hemoglobin molecule. An increase in O2 affinity is demonstrated by a shift to the left in the O2
dissociation curve (decreased p50 result). A hematopathologist expert in these disorders will evaluate
the case, appropriate tests are performed, and an interpretive report is issued.
Reference Values:
Definitive results and an interpretive report will be provided.
Clinical References: 1. Patnaik MM, Tefferi A: The complete evaluation of erythrocytosis:
congenital and acquired. Leukemia 2009 May;23(5):834-844 2. McMullin MF: The classification and
diagnosis of erythrocytosis. Int J Lab Hematol 2008;30:447-459 3. Percy MJ, Lee FS: Familial
erythrocytosis: molecular links to red blood cell control. Haematologica 2008 Jul;93(7):963-967 4.
Huang LJ, Shen YM, Bulut GB: Advances in understanding the pathogenesis of primary familial and
congenital polycythaemia. Br J Haematol 2010 Mar;148(6):844-852 5. Maran J, Prchal J: Polycythemia
and oxygen sensing. Pathologie Biologie 2004;52:280-284 6. Lee F: Genetic causes of erythrocytosis
and the oxygen-sensing pathway. Blood Rev 2008;22:321-332 7. Merchant SH, Oliveira JL, Hoyer JD,
Viswanatha DS: Erythrocytosis. In Hematopathology. Second edition. Edited by ED His. Philadelphia,
Elsevier Saunders, 2012, pp 722-723 8. Zhuang Z, Yang C, Lorenzo F, et al: Somatic HIF2A
gain-of-function mutations in paraganglioma with polycythemia. N Engl J Med 2012 Sep
6;367(10):922-930
Erythromycin Level, BA Level
Reference Values:
Serum concentration, 250 mg single dose
3 hrs: 1.1-1.7 mcg/mL
6 hrs: 0.3-0.4 mcg/mL
Any undisclosed antimicrobials might affect the results.
Test Performed By: Focus Diagnostics, Inc.
5785 Corporate Avenue
Cypress, CA 90630-4750
Erythropoietin (EPO), Serum
Clinical Information: Erythropoietin (EPO), a large (193 amino acid residue) glycoprotein
hormone secreted by the kidney, regulates RBC production. Normally, EPO levels vary inversely with
hematocrit. Hypoxia stimulates EPO release, which, in turn, stimulates bone marrow erythrocyte
production. High blood levels of RBC, hemoglobin, hematocrit, or oxygen suppress the release of EPO.
Primary polycythemia (polycythemia vera) is a neoplastic (clonal) blood disorder characterized by
autonomous production of hematopoietic cells. Increased erythrocytes result in compensatory
suppression of EPO levels. Findings consistent with polycythemia vera include hemoglobin >18.5
gm/dL, persistent leukocytosis, persistent thrombocytosis, unusual thrombosis, splenomegaly, and
erythromelalgia (dysesthesia and erythema involving the distal extremities). Secondary polycythemias
may either be due to an appropriate or an inappropriate increase in red cell mass. Appropriate secondary
polycythemias (eg, high-altitude living and pulmonary disease) are characterized by hypoxia and a
compensatory increase in red cell mass. EPO production is increased in an attempt to increase the
delivery of oxygen by increasing the number of oxygen-carrying RBCs. Some tumors secrete EPO or
EPO-like proteins; examples include tumors of the kidney, liver, lung, and brain. Such increases result
in inappropriate secondary polycythemias. Abnormal EPO levels also may be seen in renal failure. The
majority of EPO production is in the kidneys. Therefore, chronic renal failure may result in decreased
renal EPO production and, subsequently, anemia. In addition to the kidneys, the liver also produces a
small amount of EPO. Thus, anephric patients have a residual amount of EPO produced by the liver.
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