Thalassemia laboratory findings: Difference between revisions

Jump to navigation Jump to search
Line 7: Line 7:


==Overview==
==Overview==
Laboratory findings in patients with thalassemia include anemia with [[microcytosis]], abnormal bands on hemoglobin electrophoresis, and abnormal peripheral blood smear findings. Sequencing of the globin genes will reveal mutations that lead to defective globin production. In the case of hemolysis from thalassemia, laboratory findings include elevated LDH, total bilirubin, high reticulocyte count, and low haptoglobin. Importantly, the range of laboratory findings is quite diverse depending on the severity of the disease.
 
==Laboratory Findings==
==Laboratory Findings==
*'''Low hemoglobin''': Low hemoglobin, or anemia, is always found in patients with thalassemia. This is a defining and required laboratory feature of all thalassmias.
*'''Low hemoglobin''': Low hemoglobin, or anemia, is always found in patients with thalassemia. This is a defining and required laboratory feature of all thalassmias.

Revision as of 21:22, 30 November 2017

Thalassemia Microchapters

Home

Patient Information

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating Thalassemia from other Diseases

Epidemiology and Demographics

Risk Factors

Screening

Natural History, Complications and Prognosis

Diagnosis

Diagnostic Study of Choice

History and Symptoms

Physical Examination

Laboratory Findings

Electrocardiogram

X Ray

Echocardiography and Ultrasound

CT

MRI

Other Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Primary Prevention

Secondary Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

Thalassemia laboratory findings On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of Thalassemia laboratory findings

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on Thalassemia laboratory findings

CDC on Thalassemia laboratory findings

Thalassemia laboratory findings in the news

Blogs on Thalassemia laboratory findings

Directions to Hospitals Treating Thalassemia

Risk calculators and risk factors for Thalassemia laboratory findings

Please help WikiDoc by adding more content here. It's easy! Click here to learn about editing.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Shyam Patel [2]

Overview

Laboratory findings in patients with thalassemia include anemia with microcytosis, abnormal bands on hemoglobin electrophoresis, and abnormal peripheral blood smear findings. Sequencing of the globin genes will reveal mutations that lead to defective globin production. In the case of hemolysis from thalassemia, laboratory findings include elevated LDH, total bilirubin, high reticulocyte count, and low haptoglobin. Importantly, the range of laboratory findings is quite diverse depending on the severity of the disease.

Laboratory Findings

  • Low hemoglobin: Low hemoglobin, or anemia, is always found in patients with thalassemia. This is a defining and required laboratory feature of all thalassmias.
  • Elevated red blood cell mass: This is a somewhat unique feature of thalassemia. A low hemoglobin plus elevated red blood cell mass should prompt a clinician to consider thalassemia as the cause of anemia. In contrast, patients with iron-deficiency anemia have low hemoglobin but do not have elevated red blood cell mass.
  • Microcytosis: Red blood cells in thalassemia have low mean corpuscular volume (MCV), typically less than 80 femtoliters. This is similar to the MCV in iron-deficiency anemia.[1]
  • Hypochromasia: Red blood cells in thalassemia have central pallor, similar to red blood cells in iron-deficiency anemia.[1]
  • Elevated lactate dehydrogenase (LDH): This is due to hemolysis, in which intracellular contents (such as LDH) are released into the circulation.
  • Indirect, or unconjugated, hyperbilirubinemia: This is due to hemolysis, in which breaskdown products of heme are released into the bloodstream.
  • Low haptoglobin: This is due to hemolysis, in which free hemoglobin in the circulation binds to and reduces the level of haptoglobin.
  • Elevated reticulocyte count: This is due to a bone marrow compensatory response to low hemoglobin levels from thalassemia. Reticulocytes are precursors of red blood cells and thus an elevated reticulocyte count signifies an adequate compensatory attempt to produce more red blood cells.
  • Abnormal bands on hemoglobin electrophoresis: Hemoglobin electrophoresis is the gold standard diagnostic test for thalassemia. In normal persons, a hemoglobin electrophoresis will show a strong band corresponding to hemoglobin A (tetramer of 2 alpha-globin chains and 2 beta-globin chains) and a weak band corresponding to hemoglobin A2 (tetramer of 2 alpha-globin chains and 2 delta-globin chains). In thalassemia, various other bands can be present on electrophoresis. These include tetramers of gamma-globin chains (such as in Hb Barts) or tetramers of beta-globin chains (such as in HbH disease).
  • Abnormal cells on peripheral blood smear: The peripheral blood smear is perhaps the most inexpensive laboratory test that can accurately lead to a diagnosis of thalassemia. Patients with thalassemia have target cells and hypochromic (low color) and microcytic (small-sized) red blood cells.
  • Mutations in alpha-globin on DNA sequencing: This is a specialized test that can definitively determine the presence of alpha-thalassemia. Sequencing of the alpha-globin chain from peripheral blood cells can help diagnose alpha-thalassemia. This laboratory test is more expensive that the other tests. This laboratory findings is pathognomonic for alpha-thalassemia. Deletions or insertions are more common in the alpha-globin gene compared to the beta-globin gene.
  • Mutations in beta-globin on DNA sequencing: This is a specialized test that can definitively determine the presence of beta-thalassemia. Sequencing of the beta-globin chain from peripheral blood cells can help diagnose beta-thalassemia. This laboratory test is more expensive that the other tests. This laboratory findings is pathognomonic for beta-thalassemia. Point mutations (substitutions) are more common in the beta-globin gene compared to the alpha-globin gene.

Peripheral Smear

(Images shown below are courtesy of Melih Aktan MD, Istanbul Medical Faculty - Turkey, and Kyoto University - Japan, and Hospital Universitario La Fe Servicio Hematologia)


References

  1. 1.0 1.1 Chui DH, Cunningham MJ, Luo HY, Wolfe LC, Neufeld EJ, Steinberg MH (2006). "Screening and counseling for thalassemia". Blood. 107 (4): 1735–7. doi:10.1182/blood-2005-09-3557. PMC 1895412. PMID 16461765.

Template:WH Template:WS