Read every value against its reference range first, then find the pattern: which values move together, and which single test best confirms or excludes the diagnosis.
A 74-year-old woman with COPD has 1 week of worsening dyspnea and mild ankle swelling. Her examination is difficult to interpret because of hyperinflation and scattered wheezes. Which of the following blood tests best helps determine whether heart failure is contributing to her dyspnea?
A 48-year-old man has newly confirmed primary hypertension. He has no symptoms and no features suggesting a secondary cause. Which of the following studies is part of the recommended basic initial evaluation?
A 54-year-old woman had a left total knee replacement 10 days ago. She now has left calf pain, pitting edema of the left leg, tenderness along the deep veins and a calf circumference 4 cm larger than the right. She has no chest pain or dyspnea. Which of the following is the most appropriate initial diagnostic study?
A 52-year-old woman has a 9 mm asymmetric pigmented lesion on her calf with an irregular border and shades of brown, black and blue that has enlarged over 6 months. Which of the following is the most appropriate next step?
A 39-year-old man has 4 months of episodes of pounding headache, palpitations and drenching sweats lasting 10 to 20 minutes. During one episode his blood pressure was 190/110 mm Hg. Which of the following is the best initial test?
A 52-year-old woman with a duodenal ulcer completed 14 days of bismuth quadruple therapy for Helicobacter pylori 6 weeks ago. Her symptoms have resolved, and she stopped her proton pump inhibitor 2 weeks ago. Which of the following is the most appropriate test to confirm eradication?
A 57-year-old man with cirrhosis and ascites has 2 days of low-grade fever, diffuse mild abdominal tenderness and new confusion. Temperature is 38.1 C (100.6 F) and BP 112/70 mm Hg. Which of the following is the most appropriate next diagnostic step?
A 31-year-old man has a solid mass in the right testis on ultrasound. Before surgery, alpha-fetoprotein is 850 ng/mL (markedly elevated), beta-hCG is mildly elevated and LDH is normal. Which of the following conclusions is most accurate?
A 14-month-old boy has a warm, swollen right knee after a minor fall and has had large bruises since he began walking. His mother's brother had a bleeding disorder. Platelet count is 280,000/mm3, prothrombin time 12 seconds and partial thromboplastin time 68 seconds. Which of the following is the most appropriate study to confirm the diagnosis?
A 58-year-old woman has fatigue. Hemoglobin is 10.1 g/dL and mean corpuscular volume 112 µm3. Vitamin B12 is 240 pg/mL and folate is 8 ng/mL. Which of the following tests best confirms vitamin B12 deficiency?
A 5-year-old girl wakes at night scratching her anal area. Her mother saw tiny white threadlike worms near the anus last week. The girl is otherwise well and growing normally. Which of the following is the best diagnostic study?
A 50-year-old woman has 3 months of symmetric swelling of her MCP and PIP joints with morning stiffness. Which of the following laboratory tests is most specific for rheumatoid arthritis?
A 7-year-old girl has several episodes each day in which she stares blankly with fluttering eyelids for about 10 seconds, then abruptly resumes what she was doing without confusion. Hyperventilation in the office provokes an episode. Which of the following EEG findings is most expected?
A 48-year-old woman has an urge to move her legs in the evening with uncomfortable creeping sensations that are relieved by walking. The symptoms keep her from falling asleep. Neurologic examination is normal. Which of the following laboratory studies is most appropriate in the initial evaluation?
A 31-year-old man with bipolar I disorder is to begin lithium. He has no other medical conditions and takes no other medications. Which of the following pairs of studies is most important to obtain before starting lithium?
A 52-year-old woman has years of chronic cough with copious purulent sputum, recurrent chest infections and two episodes of streaky hemoptysis. Coarse crackles are heard at both bases, and a chest radiograph shows parallel linear markings in the lower lobes. Which of the following is the most accurate study to confirm the suspected diagnosis?
A 30-year-old man who moved to the United States 2 years ago from a country with a high tuberculosis rate has a tuberculin skin test read at 12 mm of induration. He has no cough, fever, night sweats or weight loss, and his examination is normal. Which of the following is the most appropriate next step?
A 70-year-old woman who started hydrochlorothiazide 2 months ago has muscle weakness and cramps. Potassium is 2.6 mEq/L and magnesium 1.6 mEq/L. Which of the following ECG findings is most likely?
A 28-year-old woman at 30 weeks of gestation is seen after a low-speed motor vehicle collision with minor abdominal impact. Her blood type is A, Rh negative, and she has never been sensitized. The fetal heart tracing is reassuring. Anti-D immune globulin is ordered. Which of the following tests determines whether she needs more than the standard dose?
A 32-year-old woman and her partner have had regular unprotected intercourse for 14 months without conceiving. Her cycles are regular every 28 days, and a mid-luteal serum progesterone confirms ovulation. She was treated for pelvic inflammatory disease at age 22. Her partner's semen analysis is normal. Which of the following is the most appropriate next diagnostic study?