Diagnostic Studies Flashcards

A 45-year-old male presents with chest pain. ECG shows ST elevation in leads V1-V4. Which additional diagnostic test is most appropriate FIRST?

Answer: Troponin I level

Troponin I is the preferred biomarker for myocardial injury and should be drawn immediately alongside ECG in suspected STEMI.

A patient with suspected deep vein thrombosis has a low pre-test probability. Which test is the most appropriate initial step?

Answer: D-dimer assay

A D-dimer assay is highly sensitive and appropriate for ruling out DVT in low pre-test probability patients; if negative, DVT is excluded.

Which finding on urinalysis is most consistent with nephrotic syndrome?

Answer: 3+ proteinuria with fatty casts

Nephrotic syndrome is characterized by massive proteinuria (>3.5 g/day) and lipiduria, often presenting as fatty casts on urinalysis.

A 60-year-old woman has a TSH of 0.05 mIU/L and a free T4 of 2.8 ng/dL. What is the most likely diagnosis?

Answer: Overt hyperthyroidism

Suppressed TSH with elevated free T4 indicates overt hyperthyroidism due to excess thyroid hormone production.

Lumbar puncture CSF analysis shows: glucose 20 mg/dL (serum 90), protein 200 mg/dL, WBC 800 (90% neutrophils). Which diagnosis is most consistent?

Answer: Bacterial meningitis

Bacterial meningitis classically presents with low CSF glucose, high protein, and predominantly neutrophilic pleocytosis.

A patient with rheumatoid arthritis has a positive anti-CCP antibody. What is the significance of this finding?

Answer: Predicts more erosive disease

Anti-CCP antibodies are highly specific for RA and their presence is associated with a more aggressive, erosive disease course.

Which imaging modality is the gold standard for diagnosing acute appendicitis in an adult?

Answer: CT abdomen with contrast

CT of the abdomen and pelvis with contrast is the gold standard for diagnosing acute appendicitis due to its high sensitivity and specificity.