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Test ID: UNHB    
Unstable Hemoglobin, Blood

Useful For Suggests clinical disorders or settings where the test may be helpful

Work-up of congenital hemolytic anemias

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Unstable hemoglobin disease is rare and may be caused by any 1 of a large number of hemoglobin variants. They are inherited as an autosomal dominant trait. The severity of the disease varies according to the hemoglobin variant; there may be no clinical symptoms or the disease may produce a mild, moderate, or severe hemolytic anemia.


The stained peripheral blood smear shows anisocytosis, poikilocytosis, basophilic stippling, polychromasia and, sometimes, hypochromia. The reticulocyte count may be increased. Splenomegaly and Heinz bodies may also be present.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Normal (reported as normal [stable] or abnormal [unstable])

Interpretation Provides information to assist in interpretation of the test results

An abnormal or unstable result is indicative of a hemoglobin variant present. Other confirmatory tests should be performed to identify the hemoglobinopathy (HBELC / Hemoglobin Electrophoresis Cascade, Blood).

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

False positives will be obtained in blood specimens containing >5% fetal hemoglobin or in specimens >1 week old.

Clinical Reference Provides recommendations for further in-depth reading of a clinical nature

Hoyer JD, Hoffman DR: The thalassemia and hemoglobinopathy syndromes. In Clinical Laboratory Medicine. Second edition. Edited by KD McMlatchey. Philadelphia, Lippincott Williams and Wilkins, 2002, pp 866-895

Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test