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Serum EPO may be helpful in distinguishing primary from secondary polycythemia, but there is significant overlap in EPO levels between the two categories.BUN, serum creatinine, and urinalysis to evaluate renal function.Half-life of carboxyhemoglobin is 4 hours, so testing should be timed to accurately reflect exposures. Co-oximetry allows for evaluation of carboxyhemoglobin and methemoglobin levels. Arterial blood gas with co-oximetry: Pao 2 may be low in cardiopulmonary diseases.CBC with differential: Polycythemia may be associated with abnormalities in other lineages.Initial workup should include the following:.Many patients may be asymptomatic with polycythemia noted on routine screening.Household members with similar symptoms may also indicate concurrent exposure to carbon monoxide.High hematocrit, hyperviscosity, or need for phlebotomy.Drug use including steroids, EPO, diuretics.Snoring, nocturnal apnea, mouth breathing, excessive daytime sleepiness, behavioral problems concerning for obstructive sleep apnea.Symptoms concerning for congenital heart disease or chronic pulmonary disease:.Headache, dizziness, syncope, transient blindness, history of thrombosis.Obesity is associated with obstructive sleep apnea.Neonates, who are born to mothers with preeclampsia or diabetes, are small for gestational age, undergo delayed cord clamping, or have certain chromosomal abnormalities (e.g., Down syndrome), are at increased risk for polycythemia during the neonatal period.EPO-producing tumors: renal cell carcinoma, hepatocellular carcinoma, hemangioblastoma, pheochromocytoma, and uterine fibroids.Hypoxia-sensing pathway defects: Mutations in the gene von Hippel Lindau (VHL) are common in certain ethnic groups (Chuvash polycythemia).Carboxyhemoglobinemia: Carbon monoxide binds to hemoglobin preferentially compared to oxygen.Methemoglobinemia: elevated levels of Fe 3+ hemoglobin, which has an increased affinity for oxygen compared to Fe 2+ hemoglobin.2,3-BPG mutase deficiency: rare defect that leads to deficiency of 2,3-BPG and decreased oxygen delivery to tissues.High oxygen-affinity hemoglobinopathies: mutation in either α- or β-globin chains leading to increased oxygen affinity and decreased oxygen delivery to tissues.Cyanotic heart disease and arteriovenous malformations: right-to-left cardiac or extracardiac shunting, resulting in desaturation of arterial blood.Chronic pulmonary disease or hypoventilation: compensation for inadequate oxygenation.High altitude: compensation for low atmospheric oxygen pressure.Some families have a mutation in the EPO receptor (EPO-R). PFCP: Erythroid progenitors are hypersensitive to EPO.The mutation JAK2 V617F is found in the vast majority of cases. PV: myeloproliferative neoplasm arising from a clonal population of abnormal hematopoietic progenitor cells with EPO-independent proliferation.The figures presented herein describe reference ranges for hematocrit and blood hemoglobin concentration during the neonatal period, accounting for gestational and postnatal age. During the first 28 days after birth, an approximately linear decrease in hematocrit/hemoglobin occurred.ĬONCLUSIONS. During the 4-hour interval after birth, hematocrit/hemoglobin values of late preterm and term neonates (35–42 weeks' gestation) increased by 3.6% ± 0.5% (mean ± SD), those of neonates of 29 to 34 weeks' gestation remained unchanged, and those of <29 weeks' gestation decreased by 6.0% ± 0.3%. No difference was seen on the basis of gender. For every week advance in gestational age, the hematocrit increased by 0.64% and the hemoglobin concentration increased by 0.21 g/dL. During the interval from 22 to 40 weeks' gestation, the hematocrit and blood hemoglobin concentration increased approximately linearly.
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Data were assembled from a multihospital health care system after exclusion of patients with a high likelihood of an abnormal value and those who were receiving blood transfusions. We sought to develop reference ranges for hematocrit and hemoglobin during the neonatal period (28 days) by using very large sample sizes and modern hematology analyzers, accounting for gestational and postnatal age and gender. Reference ranges for the hematocrit and the blood hemoglobin concentration of newborn infants have previously been reported from relatively small sample sizes by using measurement methods that now are considered outmoded. “Reference ranges” are developed when it is impossible or inappropriate to establish “normal ranges” by drawing blood on healthy normal volunteers.