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Thalassemia and Hemoglobinopathies

Thalassemia and Hemoglobinopathies. Edna D’Souza Product Specialist Clinical Diagnostic Division. Hemoglobinopathies. Types of defects. Thalassemia. Hb E Hb D Hb Q Hb J Hb C Hb Lepore Hb H. Sickle cell anemia. Caste groups that have a higher carrier rate

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Thalassemia and Hemoglobinopathies

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  1. Thalassemia and Hemoglobinopathies Edna D’Souza Product Specialist Clinical Diagnostic Division

  2. Hemoglobinopathies

  3. Types of defects Thalassemia Hb E Hb D Hb Q Hb J Hb C Hb Lepore Hb H Sickle cell anemia

  4. Caste groups that have a higher carrier rate Sindhis and Punjabis from Northern India, Bhanushali’s, Kutchis, Lohana’s from Gujarat, Mahar’s, Neobuddhist’s, Koli’s and Agri’s from Maharashtra, Gowda’s and Lingayat’s from Karnataka

  5. Scenario of Hb S carrier incidence in India (Mohanty & Colah et al, 2010)

  6. HEMOGLOBIN D HEMOGLOBIN E 3 - 50% 2 % 5 -35 %

  7. Thalassemia –National Problem • India: • Average Incidence of thalassemia carriers -3.9% (varying from 1-17%) • 1 in 25 Carriers in India!!!! • 30-40 million carriers. • Affected births/yr • Thalassemia major- 9000-10000 (1-2 majors born every hour ) • Sickle Cell Disease-~5000

  8. Thalassemias • Are a group of autosomal recessive disorders characterized by the complete absence or defect in the synthesis of the globin chains. • β- thalassemia presents itself in three forms: β thalassemia trait • asymptomatic condition wherein there is mild microcytic , hypochromic anemia • The patient suffers from the disorder. • Is unable to synthesize hemoglobin and requires blood transfusion to survive beginning as early as 6 months of age β thalassemia major β thalassemia intermedia • Genotypically they are similar to thal majors. • However phenotypically they are not dependent on regular transfusions.

  9. clinical presentation • b-thalassemia major: production of -globin chains is severely impaired • Patients with thalassemia major need blood transfusions every 3-4 weeks to maintain their hemoglobin levels • Due to transfusions they are at a risk of: • Blood transfusion related infections like hepatitis C, hepatitis B , HIV • Iron overload with a damage to all vital organs like heart, lung , liver , kidney etc. • The survival of individuals who have been well transfused and treated with appropriate chelation extends beyond 30 years.

  10. Inheritance of Hemoglobinopathies • In a marriage between a carrier and • a normal individual: • 50 % chance: children - CARRIERS • 50 % chance: children - NORMAL • In a marriage between 2 carriers: • 25 % chance: children – • NORMAL • 50 % chance: children – • CARRIERS • 25 % chance: children – • HOMOZYGOTES

  11. How to avoid baby with Thalassemia major • Follow only 2 simple steps • Step 1: Get your partner and yourself tested for thalassemia before marriage. • Step 2: If both your partner and you are thalassemia minors, consult your doctor for prenatal diagnostic test. What test is required to detect Thalassemia • A complete Blood count test • A Hemoglobin HPLC analysis to estimate Hb A2 levels.

  12. Percentage of hemoglobins

  13. Variant II hemoglobin testing system Fully automated, High-throughput hemoglobin analyzer Providing an integrated method for sample preparation, separation and determination of the relative percent of specific hemoglobins in whole blood.

  14. Why HPLC ???

  15. Sample Preparation 9STEPS to prepare hemolysate Time taken >40 MINUTES PER SAMPLE On Bio-Rad VARIANT II capped primary tubes are directly loaded. Time taken 1STEP–1MINUTE - PER SAMPLE Complete automation No manual error introduced Chances of manual error are high

  16. ELECTROPHORESISV/S HPLC Results required to be interpreted by an experienced technician Misinterpretation of bands is possible resulting in incorrect diagnosis Accurate quantification of Hb A2 and Hb F Reproducibility of results

  17. Primary tube sampling ELECTROPHORESISV/S HPLC • Automated bar-code reading Along with manual errors , the time taken in reporting could be almost a day Time required to report results highly reduced

  18. LAN ELECTROPHORESISV/S HPLC LAN Lab Network All the information of the sample chromatogram is directly transferred onto the report Complete information of all the percentages of the various hemoglobins on the report Electrophoresis strips information needs to be manually fed into the report For quantitation of bands additional densitometer required

  19. ELECTROPHORESISV/S HPLC Hb S/Hb D Hb D Hb S

  20. Can the diagnosis by electrophoresis be 100 % accurate if it has a CV of 33% Would you want to use a technique with a higher imprecision???? CAP reference for  HPLC comparison with electrophoresis with densitometry Lafferty.J. College of American Pathologists Survey 1999

  21. Electrophoresis with densitometry is ‘NOT RECOMMENDED’ CAP said in its 2003 survey “Due to high CV’s, densitometry from either alkaline electrophoresis or isoelectric focusing will not be reportable methods of HbA2 quantitation…”

  22. Evaluation of VariantCollege of American Pathologists • Analyzed 1,370 consecutive samples over a 1-year period using an automated Bio-Rad HPLC system and compared the results with standard methods • HPLC analysis detected 3 abnormal Hb patterns without corresponding gel abnormalities • HPLC is more sensitive than the standard methods for the detection of Hb variants and can be considered for routine use by hospital or clinical reference laboratories. Improved Hemoglobin Analysis by High-Performance Liquid Chromatography

  23. Hb S trait Hb E trait Hb D-Punjab trait β-thalassemiatrait Variant II Chromatogram Reports

  24. New births of beta-thalassemia major can be prevented urgent need to identify all carriers screen for thalassemia screen for thalassemia do it the right way The screening test needs to done only once in a person’s life but done the right way THANK YOU

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