1 / 17

MLAB 2401: Clinical Chemistry Keri Brophy- M artinez

MLAB 2401: Clinical Chemistry Keri Brophy- M artinez. Chapter 5: Assessment o f Iron, Porphyrins and Others. Specimen Requirements: Iron Studies. Serum without anticoagulant Plasma with heparin ( check product insert) Oxalate, citrate or EDTA binds Fe ions, so they are unacceptable

fleta
Download Presentation

MLAB 2401: Clinical Chemistry Keri Brophy- M artinez

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. MLAB 2401: Clinical ChemistryKeri Brophy-Martinez Chapter 5: Assessment of Iron, Porphyrins and Others

  2. Specimen Requirements: Iron Studies • Serum without anticoagulant • Plasma with heparin ( check product insert) • Oxalate, citrate or EDTA binds Fe ions, so they are unacceptable • Early morning sample preferred due to diurnal variation • No hemolysis

  3. Three Components Total Iron ( serum ) TIBC % Iron Saturation ( Fe Sat ) The Iron Saturation is a measurement of how “full” transferrin is Iron Study/Profiles

  4. Assessing Iron Levels and Forms • Directly measured • Iron • Transferrin • Beta globulin formed in the liver • Measured by the amount of iron it can bind • Ferritin • Best diagnostic test for IDA • Acute phase reactant

  5. Assessing Iron Levels and Forms • Indirect measure • TIBC (Total iron-binding capacity) • Measures the total amount of iron that apotransferrin can bind • Can be expressed as a percentage(percent saturation) • Ratio of serum iron to TIBC • Increased • Late pregnancy • IDA • Following hemorrhage • Following destruction of liver cells • Decreased • Decreased synthesis of transferrin • Increased loss of urine proteins

  6. Test Methodologies: Iron • Colorimetric Procedure • Separate Fe from transferrin with a strong acid • Iron is reduced from ferrous(Fe3+)to ferric(Fe2+) state • Addition of a chromogen creates a colored compound • Measurement of colored product by spectrophotometry

  7. Iron Reference Ranges • Diurnal variation • Men: 65-165 µg/dL • Women: 45-160 µg/dL • Decreased Levels • Decreased intake • Increased need • Increased loss • Increased Levels • Increased absorption • Hemolytic anemia • Lead poisoning • Pernicious anemia • Megaloblastic anemia • Hepatitis

  8. Test Methodologies:TIBC Pre-treatment and Colorimetric Method • Add Fe3+ to saturate binding sites on transferrin • MgCO3 is added to remove unbound Fe3+ • Mixture is centrifuged and the supernatant tested using the serum iron methodology

  9. Reference Ranges • Transferrin • 200-360 mg/dL • Ferritin • Male: 20-250 ng/mL • Female: 10-120 ng/mL • TIBC • 250-425 µg/dL • % saturation • 15-55

  10. Test Methodology: Hemoglobin • Electrophoresis • Discussed in separate unit

  11. Test Methodology: Porphyrins • Screening tests • Urinary PBG • Urinary ALA • Urinayr porphyrins • Quantitative Assays • URO • PROTO • COPRO • Serve to classify porphyrias

  12. Lab Methods • Watson-Schwartz for Urinary PBG( porphobilinogen) • Screen for acute intermittent porphyria • Specimen • Qualitative: fresh morning urine • Quantitative: 24 hour collection • Reference Range • <2 mg/daily

  13. Watson-Schwartz • Principle • PBG + Ehrlich’s reagent results in a red-orange chromogen • Interferences • Urobilinogen • indole

  14. Lab Methods: HgbA1c • Electrophoresis • Enzymatic Assays • HPLC • Goal is to separate hemoglobin forms within a column. Then, glycated versus total hemoglobin can be measured spectrophotometrically • Specimen requirements • EDTA whole blood • Can be non-fasting • Reference range • 4.0-6.0%

  15. Lab Methods: Myoglobin • Procedures incorporate the binding of specific antibodies to myoglobin with a resulting chemical or physical change that can be measured and correlated to myoglobin concentration • Specimen requirements • Usually plasma ( check product insert)

  16. Specimen Requirements: Lead • Whole blood • Why? Circulating lead found in the RBC • Venous sample preferred but capillary sample can be used ( must confirm positive on capillary) • Royal blue top with EDTA anticoagulant • Lead-free containers • Urine

  17. Lab Method: Lead • Test methodologies • AAS • Anodic stripping voltammetry • Reference Ranges in blood • Children< 10 µg/dL

More Related