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Difficulty: MediumOrdering Laboratory Tests

Match each patient's clinical presentation with the most appropriate targeted laboratory evaluation panel to establish the diagnosis.

  • A 65-year-old man is found to have an isolated, asymptomatic elevation of total serum protein with a normal albumin level and normal complete blood count during a routine wellness examination.Serum protein electrophoresis, serum immunofixation, and serum free light chain assay
  • A 32-year-old woman is evaluated for an unprovoked deep vein thrombosis in her left lower extremity. She has a past medical history significant for two consecutive second-trimester pregnancy losses.Lupus anticoagulant, anticardiolipin antibodies, and anti-beta-2-glycoprotein I antibodies
  • A 48-year-old woman presents with progressive fatigue, symmetrical paresthesias in her lower extremities, a smooth and beefy-red tongue, and macrocytic anemia on complete blood count.Serum vitamin B12, methylmalonic acid, and homocysteine levels
  • A 25-year-old man of Mediterranean descent presents for evaluation of lifelong microcytic anemia. Previous trials of oral iron supplementation have not improved his hemoglobin levels, and his serum ferritin is normal.Hemoglobin electrophoresis or high-performance liquid chromatography (HPLC)

Answer

The correct matches align the protein gap with electrophoresis, the unprovoked thrombosis/miscarriages with antiphospholipid antibodies, the macrocytic anemia/neuropathy with B12 testing, and the iron-refractory microcytic anemia with hemoglobin electrophoresis.
Each clinical vignette provides classic diagnostic clues for distinct hematologic disorders. A protein gap indicates a potential plasma cell dyscrasia. Thrombosis with pregnancy loss characterizes antiphospholipid syndrome. Macrocytosis with neuropathy is the hallmark of B12 deficiency. Microcytosis with normal iron stores in a Mediterranean patient is typical of beta-thalassemia trait.

Step-by-Step Solution

1
Analyze the clinical presentation of the 65-year-old man with elevated total serum protein and normal albumin.
Identified a 'protein gap' (total protein minus albumin > 4 g/dL), which strongly suggests an overproduction of immunoglobulins.
A protein gap requires evaluation for monoclonal gammopathies like MGUS or multiple myeloma.
2
Evaluate the 32-year-old woman's history of unprovoked DVT and recurrent late-term pregnancy losses.
Recognized the classic clinical criteria for antiphospholipid syndrome.
Confirming the diagnosis requires specific laboratory markers to detect antiphospholipid antibodies.
3
Assess the 48-year-old woman with macrocytic anemia, glossitis, and peripheral neuropathy.
Correlated the triad of findings with cobalamin (vitamin B12) deficiency.
Neurologic symptoms combined with megaloblastic anemia mandate testing for B12 and its metabolic intermediates.
4
Review the presentation of the 25-year-old man with lifelong microcytic anemia, normal ferritin, and no response to iron.
Suspected a hemoglobinopathy, most likely beta-thalassemia trait, given his Mediterranean heritage.
When iron deficiency is ruled out, quantitative analysis of hemoglobin subtypes is required to diagnose thalassemia.

Key Concept

Appropriate targeted laboratory testing based on clinical vignettes of common hematologic disorders.
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Ordering Laboratory Tests

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