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CLIA CCC practice questions

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Question 1Clinical Chemistry

A serum sample shows a lipemic index above the assay's interference threshold. Which pre-analytical approach is most appropriate before reporting a lipid-sensitive chemistry result?

  1. Ultracentrifuge the sample and assay the infranatant Correct answer.
  2. Incubate the sample at 56 °C for 30 minutes to clarify it
  3. Dilute the sample 1:10 with saline and multiply by 10
  4. Report the result with a comment noting the lipemia

Explanation

Ultracentrifugation physically removes the light-scattering lipid layer so the aqueous infranatant can be assayed without the turbidity interference. Simple dilution does not remove the interfering particles and can worsen proportional error, and heating can denature proteins and alter analyte values.

Question 2Clinical Chemistry

Which specimen type is generally unsuitable for routine clinical chemistry testing because of its high protein and cellular content?

  1. Plasma collected in a lithium heparin tube
  2. Serum collected in a serum separator tube
  3. Urine collected as a random clean-catch sample
  4. Whole blood collected in an EDTA tube Correct answer.

Explanation

Whole blood in EDTA is used for hematology; the cellular fraction and chelating agent interfere with many chemistry assays. Serum and heparinized plasma are standard chemistry specimens, and random urine is appropriate for many chemistry analytes.

Question 3Clinical Chemistry

A creatinine result is markedly higher in plasma than in the corresponding serum from the same patient. Which pre-analytical factor most likely explains this discrepancy?

  1. Hemolysis in the plasma specimen
  2. Use of a lithium heparin tube for the plasma Correct answer.
  3. Delayed separation of the serum specimen
  4. Use of a serum separator tube with gel

Explanation

Certain heparin salts can interfere with some creatinine methods, and heparin has also been reported to affect several enzyme-based assays. The other listed factors do not characteristically raise creatinine in plasma relative to serum.

Question 4Clinical Chemistry

Which statement best describes the purpose of the analytical measurement range (AMR) for a chemistry assay?

  1. It defines the interval of values that are clinically actionable
  2. It defines the interval of values that can be reported without dilution Correct answer.
  3. It defines the interval of values that are statistically significantly different
  4. It defines the interval of values observed in a healthy reference population

Explanation

The AMR is the range of analyte concentrations over which the assay is validated to produce results without dilution or concentration. It is distinct from the reference interval, which describes a healthy population.

Question 5Clinical Chemistry

A laboratory uses a spectrophotometric assay with a molar absorptivity of 6.22 × 10³ L·mol⁻¹·cm⁻¹ and a 1-cm path length. A solution reads an absorbance of 0.311. What is the approximate concentration in mmol/L?

  1. 0.5 mmol/L
  2. 0.05 mmol/L Correct answer.
  3. 50 mmol/L
  4. 5 mmol/L

Explanation

Using Beer's law, c = A/(ε·l) = 0.311/(6220 × 1) = 5.0 × 10⁻⁵ mol/L, which equals 0.05 mmol/L. Unit conversion between mol/L and mmol/L accounts for the factor of 1000.

Question 6Clinical Chemistry

In a fixed-time (endpoint) enzymatic assay, which factor most directly determines the measured absorbance change?

  1. The cuvette path length only
  2. The wavelength bandwidth of the monochromator
  3. The total incubation time allowed for reaction completion Correct answer.
  4. The temperature of the detector

Explanation

In an endpoint assay, the reaction is allowed to proceed to completion, so the absorbance change reflects the total amount of analyte converted, provided sufficient incubation time is given. Path length and bandwidth affect signal magnitude but not the completeness of the reaction.

Question 7Clinical Chemistry

Which instrument component is responsible for selecting a narrow band of wavelengths from a continuous light source in a spectrophotometer?

  1. Chopper
  2. Cuvette
  3. Photomultiplier tube
  4. Monochromator Correct answer.

Explanation

The monochromator uses a prism or diffraction grating to isolate a narrow wavelength band from the polychromatic source. The photomultiplier detects light, the cuvette holds the sample, and the chopper modulates the beam.

Question 8Clinical Chemistry

A reaction-rate assay for an enzyme shows a nonlinear absorbance curve within the first 30 seconds. What is the most appropriate interpretation?

  1. The assay should be read during the initial linear phase Correct answer.
  2. The assay is complete and the final absorbance should be used
  3. The enzyme concentration is too high to measure
  4. The substrate is exhausted

Explanation

Rate assays must be read during the linear portion of the reaction curve, where the rate is proportional to enzyme activity. Nonlinearity early in the reaction suggests a lag phase or interference, so the reading should be taken after linearity is established.

Question 9Clinical Chemistry

Which electrolyte is primarily responsible for maintaining the osmotic gradient across cell membranes in the extracellular fluid?

  1. Magnesium
  2. Calcium
  3. Potassium
  4. Sodium Correct answer.

Explanation

Sodium is the dominant extracellular cation and largely determines plasma osmolality and water distribution. Potassium is predominantly intracellular, while calcium and magnesium are present at much lower concentrations and serve other roles.

Question 10Clinical Chemistry

A patient's measured osmolality is 320 mOsm/kg while the calculated osmolality is 280 mOsm/kg. Which condition best explains this osmolal gap?

  1. Ingestion of an unmeasured osmotically active substance Correct answer.
  2. Hypoproteinemia
  3. Hyperkalemia
  4. Hypernatremia

Explanation

An osmolal gap reflects the presence of osmotically active substances not accounted for by sodium, glucose, and urea, such as ethanol or methanol. Hypernatremia would raise both measured and calculated values proportionally.

Question 11Clinical Chemistry

Which laboratory finding is most consistent with pseudohyponatremia caused by severe hyperproteinemia?

  1. Low measured sodium with normal measured osmolality Correct answer.
  2. Elevated measured sodium with normal measured osmolality
  3. Normal measured sodium with low measured osmolality
  4. Low measured sodium with elevated measured osmolality

Explanation

In pseudohyponatremia, the aqueous phase is diluted by excess protein or lipid, lowering the reported sodium while true osmolality remains normal. Measured osmolality by freezing point is unaffected by the volume displacement effect.

Question 12Clinical Chemistry

Which enzyme is most specific for cholestatic liver injury among the following?

  1. Alkaline phosphatase Correct answer.
  2. Alanine aminotransferase
  3. Aspartate aminotransferase
  4. Lactate dehydrogenase

Explanation

Alkaline phosphatase is elevated in cholestasis because it is concentrated in the biliary canalicular membrane. Aminotransferases reflect hepatocellular injury, and lactate dehydrogenase is nonspecific.

Question 13Clinical Chemistry

A patient has an AST/ALT ratio greater than 2 with elevated liver enzymes and a history of heavy alcohol use. Which pattern does this most likely represent?

  1. Wilson disease
  2. Alcoholic liver disease Correct answer.
  3. Acute viral hepatitis
  4. Biliary obstruction

Explanation

Alcoholic liver disease classically produces an AST/ALT ratio above 2, partly because alcohol depletes pyridoxal-5-phosphate and reduces ALT synthesis. Viral hepatitis and cholestasis typically show different enzyme patterns.

Question 14Clinical Chemistry

Which bilirubin fraction is covalently bound to albumin and may remain elevated long after resolution of hemolysis?

  1. Delta bilirubin Correct answer.
  2. Bilirubin diglucuronide
  3. Conjugated bilirubin
  4. Unconjugated bilirubin

Explanation

Delta bilirubin is conjugated bilirubin covalently bound to albumin, so it clears slowly and can persist after the underlying cause resolves. Unconjugated and conjugated bilirubin are not albumin-bound in this stable manner.

Question 15Clinical Chemistry

Which cardiac biomarker is considered the preferred marker for detecting acute myocardial infarction because of its high specificity?

  1. Cardiac troponin I Correct answer.
  2. Myoglobin
  3. Lactate dehydrogenase
  4. Creatine kinase MB

Explanation

Cardiac troponin I and T are highly specific to myocardium and are the preferred biomarkers for acute myocardial infarction. CK-MB and myoglobin are less specific because they can rise with skeletal muscle injury.

Question 16Clinical Chemistry

A patient's blood glucose is 250 mg/dL and the measured hemoglobin A1c is 5.0%. Which condition most likely explains the discrepancy?

  1. Chronic kidney disease
  2. Recent onset of diabetes
  3. Iron deficiency anemia
  4. Shortened red cell survival Correct answer.

Explanation

A1c reflects glucose exposure over the red cell lifespan, so shortened red cell survival lowers the value disproportionately to current glycemia. Iron deficiency and chronic kidney disease tend to raise A1c relative to true glycemia.

Question 17Clinical Chemistry

Which glucose meter interference is most likely in a patient receiving high-dose intravenous vitamin C?

  1. Falsely elevated readings with hexokinase methods
  2. Falsely elevated readings with glucose dehydrogenase methods
  3. Falsely low readings with glucose oxidase methods Correct answer.
  4. No interference with any method

Explanation

High ascorbate concentrations can consume peroxide or reduce the chromogen in glucose oxidase-based systems, producing falsely low results. Hexokinase-based laboratory methods are less affected.

Question 18Clinical Chemistry

In a patient with diabetic ketoacidosis, which laboratory finding is most characteristic?

  1. Elevated anion gap with hypokalemia only
  2. Elevated anion gap with ketonemia Correct answer.
  3. Normal anion gap with hyperchloremia
  4. Low anion gap with hypernatremia

Explanation

DKA produces a high anion gap metabolic acidosis from accumulation of ketone bodies such as beta-hydroxybutyrate and acetoacetate. Hyperchloremic normal-gap acidosis is more typical of bicarbonate loss or recovery phase.

Question 19Clinical Chemistry

Which analyte is most appropriate for monitoring long-term glycemic control in a patient with a hemoglobin variant that interferes with the immunoassay?

  1. Glycated albumin measured by the same immunoassay
  2. Random plasma glucose
  3. Urine glucose
  4. Fructosamine Correct answer.

Explanation

Fructosamine reflects glycation of serum proteins over roughly two to three weeks and is unaffected by hemoglobin variants. Random glucose and urine glucose provide only snapshot information and do not assess chronic control.

Question 20Clinical Chemistry

Which protein is the primary carrier of iron in plasma?

  1. Ceruloplasmin
  2. Transferrin Correct answer.
  3. Ferritin
  4. Haptoglobin

Explanation

Transferrin transports iron from absorption sites and storage to tissues. Ferritin stores iron intracellularly, haptoglobin binds free hemoglobin, and ceruloplasmin carries copper.

Question 21Clinical Chemistry

A patient has low serum iron, elevated total iron-binding capacity, and low ferritin. Which condition is most consistent with these findings?

  1. Hereditary hemochromatosis
  2. Iron deficiency anemia Correct answer.
  3. Hemolytic anemia
  4. Anemia of chronic disease

Explanation

Iron deficiency produces low iron and ferritin with a compensatory rise in transferrin and total iron-binding capacity. Anemia of chronic disease typically shows low iron with low or normal TIBC and normal or elevated ferritin.

Question 22Clinical Chemistry

Which principle underlies the measurement of serum creatinine by the Jaffe reaction?

  1. Formation of a colored complex between creatinine and picrate Correct answer.
  2. Enzymatic oxidation of creatinine to creatine
  3. Ion-exchange chromatography with conductivity detection
  4. Immunoassay with a creatinine-specific antibody

Explanation

The Jaffe reaction forms an orange-red complex between creatinine and picrate in alkaline solution, measured spectrophotometrically. It is subject to interference from non-creatinine chromogens such as proteins and ketones.

Question 23Clinical Chemistry

A patient's measured creatinine clearance is 120 mL/min while the estimated GFR from serum creatinine is 45 mL/min/1.73 m². Which factor most likely accounts for this discrepancy?

  1. Increased tubular secretion of creatinine Correct answer.
  2. Decreased dietary protein intake
  3. Use of a first-void urine specimen
  4. Delayed transport of the sample to the laboratory

Explanation

Creatinine is secreted by the proximal tubule in addition to being filtered, so measured clearance can overestimate true GFR, especially in advanced kidney disease. Dietary protein and specimen timing do not explain a systematic overestimation of this kind.

Question 24Clinical Chemistry

Which electrolyte abnormality is most characteristic of primary hyperaldosteronism?

  1. Hyperkalemia and metabolic acidosis
  2. Hyperkalemia and hypernatremia
  3. Hypokalemia and metabolic alkalosis Correct answer.
  4. Hypokalemia and metabolic acidosis

Explanation

Aldosterone promotes sodium reabsorption and potassium and hydrogen excretion, so excess aldosterone causes hypokalemia with metabolic alkalosis. Hyperkalemia with acidosis is more typical of hypoaldosteronism.

Question 25Clinical Chemistry

Which analyte is measured to assess the adequacy of dialysis clearance of small solutes such as urea?

  1. Creatinine kinase
  2. Beta-2 microglobulin
  3. Urea reduction ratio Correct answer.
  4. Cystatin C

Explanation

The urea reduction ratio compares pre- and post-dialysis blood urea nitrogen and reflects small-solute clearance during a dialysis session. Beta-2 microglobulin and cystatin C reflect different aspects of renal function or middle-molecule clearance.

Question 26Clinical Chemistry

Which specimen collection tube additive is preferred for a serum chemistry panel because it promotes clot formation without diluting the sample?

  1. Serum separator with clot activator and gel Correct answer.
  2. Sodium citrate
  3. Heparin without gel
  4. Potassium EDTA

Explanation

Serum separator tubes contain a clot activator and a thixotropic gel that separates serum from cells during centrifugation, yielding cell-free serum without the dilution that liquid additives can cause. Citrate and EDTA are liquid or chelating additives intended for coagulation and hematology respectively.

Question 27Clinical Chemistry

A fasting serum sample is visibly lipemic. Which mechanism best explains spurious results in a spectrophotometric assay?

  1. Light scattering from lipid particles increases apparent absorbance Correct answer.
  2. Lipids bind the antibody and increase immunoassay signal
  3. Lipemia increases the cuvette path length
  4. The lipids chemically react with the chromogen to suppress color development

Explanation

Lipid particles scatter and absorb light, raising the apparent absorbance and biasing photometric results, particularly at shorter wavelengths. This is a physical interference rather than a chemical reaction with the reagent.

Question 28Clinical Chemistry

Which statement correctly describes the reference method concept in clinical chemistry?

  1. It is the method with the lowest cost per test
  2. It is a method of demonstrated accuracy used to assign values to calibrators and assess other methods Correct answer.
  3. It is the fastest routine method available in the laboratory
  4. It is any method cleared by a regulatory body for clinical use

Explanation

A reference method has been validated for accuracy by a recognized authority and serves as the anchor for value assignment and for evaluating field methods. Routine methods are judged against it, not the reverse.

Question 29Clinical Chemistry

A laboratory reports a sodium of 128 mmol/L on an ion-selective electrode using a direct (undiluted) measurement. Which statement about direct versus indirect ISE is most accurate?

  1. Direct ISE measures sodium activity in undiluted sample and is less affected by hyperproteinemia than indirect ISE Correct answer.
  2. Indirect ISE is preferred because dilution eliminates all electrolyte interference
  3. Indirect ISE measures undiluted sample and is unaffected by protein concentration
  4. Direct ISE reports total sodium concentration rather than activity

Explanation

Direct ISE measures sodium activity in the undiluted specimen, so it is not subject to the volume-displacement artifact that affects indirect ISE in samples with very high protein or lipid content. Indirect ISE dilutes the sample and can therefore report falsely low sodium in pseudohyponatremia.

Question 30Clinical Chemistry

An enzymatic assay is run with a sample blank because the specimen is moderately icteric. What is the purpose of the sample blank in this context?

  1. To calibrate the photometer wavelength accuracy
  2. To confirm that the enzyme is fully saturated with substrate
  3. To measure reagent absorbance alone before adding sample
  4. To subtract absorbance contributed by the specimen itself from the final reading Correct answer.

Explanation

A sample blank measures the absorbance of the specimen under assay conditions without the chromogenic reaction, and that value is subtracted to correct for endogenous specimen absorbance such as bilirubin. A reagent blank, by contrast, measures reagent absorbance without sample.

Question 31Clinical Chemistry

A creatinine result by the Jaffe reaction is markedly higher than the enzymatic creatinine result on the same sample. Which substance most likely caused the discrepancy?

  1. Acetoacetate Correct answer.
  2. Glucose
  3. Bilirubin
  4. Urea

Explanation

The alkaline picrate (Jaffe) reaction is subject to positive interference from non-creatinine chromogens, notably ketones such as acetoacetate, which react with picrate. Enzymatic creatinine methods are more specific and would not show the same elevation.

Question 32Clinical Chemistry

Which best describes the analytical basis for ion-selective electrode measurement of potassium?

  1. Photometric measurement of a potassium-dye complex
  2. Amperometric measurement of current generated by potassium oxidation
  3. Potentiometric measurement of a potential difference across a potassium-selective membrane Correct answer.
  4. Conductivity change caused by potassium binding to a chelator

Explanation

Ion-selective electrodes are potentiometric devices: the potential developed across a selective membrane varies with the logarithm of ion activity according to the Nernst equation. The measured potential is converted to concentration using calibration.

Question 33Clinical Chemistry

A troponin result from one immunoassay platform is 0.04 ng/mL and from another is 0.12 ng/mL on the same specimen. Which concept best explains this?

  1. Troponin degrades rapidly and the difference reflects specimen aging
  2. The two assays use different antibodies and standardization, so results are not interchangeable Correct answer.
  3. Troponin is measured in whole blood only
  4. The higher result is a false positive from heterophile antibodies

Explanation

High-sensitivity troponin assays differ in antibody epitopes, calibration and reported units, so numeric results across platforms are not directly comparable. Serial monitoring should use the same method and the assay-specific reference limit.

Question 34Clinical Chemistry

A laboratory wants to detect a small but real change in serial results for the same analyte. Which parameter best defines the smallest change that exceeds analytical noise?

  1. Reference interval width
  2. Reference change value derived from analytical and biological variation Correct answer.
  3. Coefficient of variation of the calibrator
  4. Total error at the medical decision point

Explanation

The reference change value combines analytical imprecision and within-subject biological variation to define the difference between two serial results that is likely to be clinically meaningful. It is the appropriate tool for interpreting change in an individual over time.

Question 35Clinical Chemistry

A glucose result is reported as 90 mg/dL by a method with a hexokinase reference procedure. Which statement about traceability is most correct?

  1. Traceability is only required for tests with regulatory clearance
  2. Traceability is established by any internal quality control result within limits
  3. Traceability requires that the routine method be compared to a higher-order reference procedure through an unbroken calibration chain Correct answer.
  4. Traceability means the result is automatically accurate in every patient

Explanation

Metrological traceability means the routine result can be related to a reference standard or reference method through an unbroken chain of calibrations, each with stated uncertainty. Internal QC verifies performance but does not itself establish traceability.

Question 36Clinical Chemistry

A laboratory calculates an estimated glomerular filtration rate using the CKD-EPI creatinine equation. Which statement about this equation is most accurate?

  1. It requires a 24-hour urine collection to be valid
  2. It is interchangeable with measured creatinine clearance in all patients
  3. It is valid only when the serum creatinine is within the reference interval
  4. It incorporates age and sex and is normalized to body surface area Correct answer.

Explanation

The CKD-EPI creatinine equation uses serum creatinine together with age and sex, and the result is expressed per 1.73 m2 of body surface area. It is an estimate and may diverge from measured clearance, particularly at extremes of muscle mass.

Question 37Hematology

Which erythrocyte precursor is the first in the maturation sequence to lose its nucleus?

  1. Pronormoblast
  2. Orthochromic normoblast
  3. Polychromatophilic normoblast
  4. Reticulocyte Correct answer.

Explanation

The reticulocyte is the anucleate stage that follows extrusion of the nucleus from the orthochromic normoblast. Residual ribosomal RNA persists for roughly one to two days and is what stains as reticulum with supravital dye. All earlier normoblast stages retain a nucleus.

Question 38Hematology

A peripheral smear shows many schistocytes, thrombocytopenia, and elevated LDH with a negative Coombs test. Which process do these findings most directly reflect?

  1. Megaloblastic arrest
  2. Hereditary spherocytosis
  3. Autoimmune hemolysis
  4. Microangiopathic hemolysis Correct answer.

Explanation

Schistocytes indicate mechanical fragmentation of red cells within the circulation, as seen in microangiopathic processes such as TTP and HUS. The combination of thrombocytopenia and elevated LDH with a negative direct antiglobulin test supports mechanical destruction rather than immune hemolysis.

Question 39Hematology

Which laboratory finding is most characteristic of iron deficiency anemia before treatment?

  1. Increased ferritin with normal total iron-binding capacity
  2. Decreased ferritin with increased total iron-binding capacity Correct answer.
  3. Increased ferritin with decreased total iron-binding capacity
  4. Normal ferritin with decreased total iron-binding capacity

Explanation

Iron deficiency depletes storage iron, so serum ferritin falls, while transferrin rises in compensation, increasing total iron-binding capacity. This produces the classic low ferritin, high TIBC, low saturation pattern. Ferritin is the most sensitive storage marker in uncomplicated deficiency.

Question 40Hematology

A patient with chronic kidney disease has a normocytic anemia with low reticulocyte count and normal iron studies. Which mechanism best explains the anemia?

  1. Inadequate erythropoietin production Correct answer.
  2. Impaired hemoglobin synthesis
  3. Peripheral destruction of red cells
  4. Defective globin chain production

Explanation

The kidney produces erythropoietin, and failing renal parenchyma reduces its output, producing a hypoproliferative normocytic anemia with an inappropriately low reticulocyte response. Iron studies are typically normal because the defect is not substrate availability.

Question 41Hematology

Which finding on the peripheral smear is most suggestive of megaloblastic anemia?

  1. Pencil cells and thrombocytosis
  2. Hypersegmented neutrophils and macroovalocytes Correct answer.
  3. Spherocytes and bite cells
  4. Target cells and basophilic stippling

Explanation

Impaired DNA synthesis in megaloblastic anemia produces nuclear-cytoplasmic asynchrony, yielding large oval red cells and neutrophils with six or more lobes. These features reflect the underlying vitamin B12 or folate deficiency.

Question 42Hematology

A 30-year-old woman has a prolonged PTT, normal PT, and a mixing study that does not correct after two hours. Which explanation fits best?

  1. A clotting factor deficiency is present
  2. Vitamin K deficiency is present
  3. Heparin contamination is present
  4. A time-dependent factor inhibitor is present Correct answer.

Explanation

Failure of a mixing study to correct after incubation indicates an inhibitor rather than a factor deficiency, because the added normal plasma supplies the missing factor. A time-dependent inhibitor such as a factor VIII antibody typically shows this pattern.

Question 43Hematology

Which test best confirms the presence of a lupus anticoagulant?

  1. Factor VIII activity level
  2. Platelet aggregation with ristocetin
  3. Phospholipid-dependent clotting assay with confirmatory phospholipid addition Correct answer.
  4. Bleeding time

Explanation

Lupus anticoagulants prolong phospholipid-dependent clotting tests, and confirmation relies on showing that adding excess phospholipid shortens the prolonged time. This demonstrates the phospholipid dependence of the inhibitor.

Question 44Hematology

A patient has a markedly elevated D-dimer, low fibrinogen, and prolonged PT and PTT with schistocytes. Which condition is most consistent?

  1. Disseminated intravascular coagulation Correct answer.
  2. Immune thrombocytopenia
  3. Hemophilia A
  4. von Willebrand disease

Explanation

DIC consumes coagulation factors and fibrinogen while generating fibrin degradation products, so D-dimer rises and fibrinogen falls with prolongation of both PT and PTT. Microangiopathic schistocytes reflect fibrin deposition in small vessels.

Question 45Hematology

Which hemoglobin is the major adult form and consists of two alpha and two beta chains?

  1. Hemoglobin F
  2. Hemoglobin H
  3. Hemoglobin A2
  4. Hemoglobin A Correct answer.

Explanation

Hemoglobin A, comprising two alpha and two beta globin chains, makes up the great majority of adult hemoglobin. Hemoglobin A2 and hemoglobin F are minor adult components. Hemoglobin H is a pathologic tetramer of beta chains.

Question 46Hematology

A smear from a patient with sickle cell disease shows elongated, boat-shaped red cells. What are these called?

  1. Dacrocytes
  2. Stomatocytes
  3. Schistocytes
  4. Sickle cells Correct answer.

Explanation

Sickle cells are elongated, crescent or boat-shaped red cells formed when deoxygenated hemoglobin S polymerizes and distorts the membrane. Their presence supports a sickling hemoglobinopathy.

Question 47Hematology

Which laboratory pattern is most consistent with beta thalassemia trait?

  1. Microcytosis with elevated hemoglobin A2 Correct answer.
  2. Normocytosis with elevated hemoglobin F
  3. Macrocytosis with normal hemoglobin A2
  4. Microcytosis with low hemoglobin A2

Explanation

Beta thalassemia trait reduces beta chain output, so compensatory delta chain synthesis raises hemoglobin A2 above the reference range. The red cells are microcytic with a normal or high red cell count.

Question 48Hematology

A patient of Mediterranean descent has microcytic anemia with normal iron studies and a normal hemoglobin A2. Which diagnosis should be considered?

  1. Iron deficiency anemia
  2. Anemia of chronic disease
  3. Sideroblastic anemia
  4. Alpha thalassemia Correct answer.

Explanation

Alpha thalassemia produces microcytosis without a hemoglobin A2 elevation, since the defect lies in alpha chain production. Normal iron studies help exclude iron deficiency and anemia of chronic disease.

Question 49Hematology

Which cell is the characteristic malignant cell of Hodgkin lymphoma on lymph node biopsy?

  1. Flame cell
  2. Reed-Sternberg cell Correct answer.
  3. Smudge cell
  4. Auer rod

Explanation

Reed-Sternberg cells are large, often binucleate cells with prominent nucleoli that define Hodgkin lymphoma. They typically lie in an inflammatory background.

Question 50Hematology

A patient has a leukoerythroblastic picture with teardrop cells and splenomegaly. Which process is most likely?

  1. Marrow infiltration with fibrosis Correct answer.
  2. Warm autoimmune hemolysis
  3. Immune thrombocytopenia
  4. Iron deficiency anemia

Explanation

Marrow replacement by fibrosis or tumor disrupts the normal barrier, releasing immature red and white cells into blood, producing a leukoerythroblastic picture with teardrop forms. Splenomegaly results from extramedullary hematopoiesis and portal congestion.