Hemoglobinopathy Work-Up at Hematology Laboratory of Tufts Medical Center: 3-years Experience
S Kondratiev, SM Johnson, H-Y Luo, DHK Chui, IB Rosenwald.. Tufts Medical Center, Boston, MA; Boston Medical Center, Boston
Background: Hemoglobinopathies are common inherited diseases. No single laboratory test has adequate sensitivity and specificity for detection of all hemoglobinopathy syndromes; therefore a group of tests is required. The purpose of this study is to define a practical approach for the diagnosis of hemoglobinopathies at our Medical Center.
Design: We retrospectively reviewed all adult cases (18 y and older) submitted for hemoglobinopathy work-up at the Tufts Medical Center between 2005-2007. Initially, cases were stratified based on HPLC and MCV results. Zinc protoporphyrin (ZPP) for possible iron deficiency and molecular tests were performed if indicated.
Results: A total of 832 cases were referred for hemoglobinopathy work-up during the 3-y period, initially with CBC, blood smear and HPLC. Among the 619 cases with normal HPLC, 237 had microcytosis (MCV<80). 57 cases had normal ZPP (80) and were sent for DNA-based molecular testing. 93% (53 cases) had -thalassemia, and only 7% (4 cases) had no globin gene mutation detected. Of the 180 cases with ZPP>80, most were referred for iron studies. 44 cases, however, were sent for molecular testing, mainly because of target cells found on blood smear. 70% (31 cases) showed -thalassemia (28), - and -thalassemia (1), and variant Hb (2). The majority of the 382 cases with normal HPLC and MCV80 did not require further study, but 3 cases were sent for molecular testing as part of family study. They showed -thalassemia (1), variant Hb (1), and no mutation (1). The group with abnormal HPLC included 213 cases. There were 95 cases with MCV<80 and elevated HbA2 and/or HbF. Molecular study was done in 35 cases and confirmed abnormalities in 91% (32 cases) including -thalassemia (17), -thalassemia (6), HbH disease (2), - and -thalassemia (2), variant Hb (5) and no mutation in 9% (3 cases). Among 22 cases with MCV80 and elevated HbA2 and/or HbF, 12 cases were sent for molecular study and detected HPFH (1), HPFH and -thalassemia (1), -thalassemia (1), and normal test (9). Furthermore, HbS (51 cases), HbC (22), HbS/C (5), HbE (13) were detected by HPLC. Molecular study was required in 41 cases based on MCV and morphology and confirmed Hb S, C, or E (13) frequently in combination with -thalassemia (26).
Conclusions: These results confirm the high frequency and complexity of hemoglobinopathies encountered in today's US populations. The study emphasizes the importance of clinical laboratory and molecular testing in making the correct diagnosis.
Wednesday, March 11, 2009 1:00 PM
Poster Session VI # 207, Wednesday Afternoon