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Test Name:
Hemoglobin, Fetal
- SBMF No:
23061 - Performance Lab Name:
Manual Lab - Test Mnemonic:
HGBF - ABN:
Not required - CPT Code:
83030 - LOINC Code:
42246-9 - Also Known As:
Fetal Hemoglobin - Spec Type:
Whole blood - Spec Container:
Lavender top (EDTA) tube - Pref Vol:
1.0 mL - Min Vol:
0.5 mL - Fasting:
No - Spec Collect:
Routine venipuncture - Spec Process:
Do not centrifuge
Do not remove plasma from cells - Spec Store Transport:
Refrigerated - Spec Stability:
1 week refrigerated (2-8°C) - Methodology:
High Performance Liquid Chromatography (HPLC) - Use:
Evaluate hemoglobinopathies, hemolytic anemia
Diagnose hereditary persistence of fetal hemoglobin
Diagnose thalessemia; evaluate sickling hemoglobins - Clinical Significance:
Fetal hemoglobin is formed of two alpha chains and two beta chains. It is the major hemoglobin during fetal life. Hb F levels decrease after birth by about 3% to 4% per week. In 2-3 weeks fetal hemoglobin is about 65%. By 6 months of age fetal hemoglobin is less than 2% of the total hemoglobin. See graph. The oxygen dissociation curve of Hb F is shifted to the left as compared with normal Hb A. This may be due to decreased binding of 2,3-DPG by Hb F ( -chains). This facilitates placental oxygen transfer. With erythroblastosis fetalis and anoxic states of the newborn, however, Hb F is proportionally lower than in a normal newborn. Some 15 inherited abnormalities of chain structure have been described but most are without clinical significance (fetal Hgb normally forms less than 2% of total hemoglobin). An exception is Hb F Poole which has been reported as a cause of hemolytic disease of the newborn.
In the adult, hereditary persistence of fetal hemoglobin (HPFH) of multiple varieties, is associated with varying elevations of Hb F. The homozygous form of HPFH is found only in blacks. In the heterozygous state, the Hb F level is 15% to 35% in the black type, and 5% to 20% in the Greek type. Homozygous ßthalassemia is associated with Hb F levels of less than 10% to greater than 90%. About 50% of heterozygotes for ßthalassemia have elevated levels around 2%, rarely greater than 5%. The remainder have normal Hb F. Heterozygous S/ß thalassemia may have Hb F in the 5% to 20% range. With homozygous Hb S disease the level of Hb F varies from 0% to 20%. Other conditions associated with elevated Hb F include various anemias, spherocytosis, Fanconi, acquired aplastic, hemolytic hypoplastics, megaloblastic, myelophthisic, and untreated pernicious anemia; all types of leukemia (especially erythroleukemia and juvenile chronic myelogenous leukemia), multiple myeloma and lymphomas, metastatic disease of the bone marrow; pregnancy; miscellaneous disorders reported include infants small for gestational age, infants with chronic intrauterine anoxia with developmental anomalies; during anticonvulsant drug therapy; diabetes; hyper- and hypothyroidism; and macroglobulin. Elevation of Hb F should, then, raise the question of possible underlying disease. - Reference Range:
0-3 weeks: 0.0-65.0%
3 weeks to 6 months: 0.0-2.0%
6 months to adult: 0.0-1.0% - Additional Test Info:
Limitations:
The following clinical conditions may result in an increased level of fetal hemoglobin-containing red cells or F cells detected, and should not be confused with fetal red cells seen with fetal-maternal hemorrhage: severe anemia, hereditary persistence of fetal hemoglobin, sickle cell anemia, and thalassemia. - Day Run:
Tue, Fri - Time Run:
8:00 am - Time Reported:
5:00 pm - Test Type:
CHEMISTRY
