Porphyrins and Hemoglobin

The primary purpose of porphyrins in the human body is to a. Chelate free hemoglobin b. Contribute to the synthesis of heme c. Transport ferrous iron d. Transport oxygen to tissues

The chemical structure of porphyrin is described as a(n) a. Cyclic tetrapyrrole b. Heterocyclic pyrrole c. Linear tetrapyrrole d. Oxygen-binding prosthetic group

Which statement correctly describes a porphyrin property? a. Porphyrins absorb light in the visible region of the spectrum and fluoresce. b. Porphyrins are not soluble in aqueous solution. c. Porphyrins are oxidized to porphyrinogens when exposed to air. d. Porphyrins produced spontaneously are functional compounds.

The porphyrias can be classified according to disease symptoms as a. Congenital or acquired b. Erythropoietic or hepatic c. Hematologic or muscular d. Neurologic or cutaneous

Elevated urinary PBG concentration with negative fecal porphyrin results indicates a. Acute intermittent porphyria (AIP) b. Erythropoietic protoporphyria (EPP) c. Hereditary coproporphyria (HCP) d. Porphyria cutanea tarda (PCT)

Porphyria cutanea tarda (PCT) is identified by a. Chromatographic analysis of a 24-h urine collection b. Scanning fluorescence of plasma c. Screening for PBG in a random urine specimen d. Separation of fecal porphyrins in a 24-h specimen

Suspected erythropoietic protoporphyria (EPP) is evaluated by a. Assessing plasma or whole blood for protoporphyrin b. Enzymatic measurement of hydroxymethylbilane synthase c. HPLC analysis of a urine specimen d. Molecular testing for ferrochelatase

Porphobilinogen often is measured in the urine using a. Chromatography b. Electrophoresis c. Spectrophotometry d. The Watson-Schwartz method

In the clinical laboratory, testing to identify specific porphyrins is performed using a. Chemical derivatization and spectrophotometry b. Fluorometric emission scanning c. Liquid chromatography with fluorescent detection d. Thin layer chromatography

Specimens collected for evaluation of porphyria should be a. Allowed to clot at room temperature for an hour b. Diluted to less than 25 mg/dL creatinine b. Exposed to light and air to oxidize the analytes d. Protected from light and stored cold

Inherited disorders in which a genetic defect causes abnormalities in rate and quantity of synthesis of structurally normal polypeptide chains of the hemoglobin molecule are called a. Hemoglobinopathies b. Molecular dyscrasias c. Porphyrias d. Thalassemias

Molecular diagnostic techniques that can help diagnose hemoglobin disorders such as hemoglobinopathies and thalassemias include a. Biochemical separation, identification, and quantification of mixture components b. Separation of macromolecules and their fragments, based on their size and charge c. DNA amplification, hybridization, and nucleotide sequencing d. The use of specific monoclonal antibodies

Which of the following abnormal hemoglobins, found frequently in individuals from Southeast Asia, migrates with hemoglobin A2 on cellulose acetate electrophoresis? a. Hemoglobin C b. Hemoglobin D c. Hemoglobin E d. Hemoglobin Lepore

Which type of alpha-thalassemia results from deletion of three genes and produces a moderate hemolytic anemia? a. Hemoglobin Bart’s b. Hemoglobin H disease c. Hydrops fetalis d. Thalassemia trait

The most effective way to quantitate hemoglobin A2 is by a. Alkali denaturation test b. Citrate agar electrophoresis c. Column chromatography d. Densitometry

Serum or plasma myoglobin Concentrations are used as a. An early marker of acute myocardial infarction b. An indicator of congestive heart failure c. Lead poisoning indicator d. Liver function tests

Which of the following is the best test to differentiate beta-thalassemia minor from iron deficiency anemia? a. Complete blood count b. Hemoglobin A2 quantitation c. Hemoglobin electrophoresis (cellulose acetate, alkaline pH) d. Solubility test

Which is the correct sequence of electrophoretic migration of hemoglobins from slowest to fastest on cellulose acetate at an alkaline pH? a. A, F, S, C b. C, A, S, F c. C, S, A, F d. C, S, F, A

High-resolution melting (HRM) is a technique that can be used post PCR amplification as long as the probe utilized during the amplification process is complexed with a fluorescent detection dye that recognizes a. Single-stranded DNA b. Double-stranded DNA c. cDNA d. Specific primers

The two main sites of production of heme are a. Heart and lung b. Liver and bone marrow c. Liver and spleen d. Muscle and blood

Which hemoglobin is resistant to alkali denaturation in NaOH? a. Hb A b. Hb C c. Hb F d. Hb S

A patient has an abnormal hemoglobin band that migrates with Hb S on cellulose acetate (pH 8.4) hemoglobin electrophoresis. The solubility test is negative. Which test should be performed next? a. Citrate agar (pH 6.2) electrophoresis b. HbA2 quantitation c. Acid elution stain d. Blood film evaluation

Silent carriers of alpha-thalassemia are missing how many alpha genes? a. 1 b. 2 c. 3 d. 4

Which hemoglobin contains four gamma chains and has an extremely high affinity for oxygen? a. Hb Bart’s b. Hb F c. Hb Gower I d. Hb Portland I