Quantitative Reasoning and Numeracy Flashcards

A patient needs 2.5 mg of a drug per kg of body weight. The patient weighs 88 kg. The drug is available as a 50 mg/mL solution. How many mL should be administered?

Answer: 4.4 mL

Total dose = 2.5 mg/kg × 88 kg = 220 mg. Volume = 220 mg ÷ 50 mg/mL = 4.4 mL.

A clinical trial reports a risk ratio (RR) of 1.45 for myocardial infarction in patients on Drug X vs. placebo. Which numerical statement BEST interprets this finding?

Answer: Patients on Drug X have a 45% higher risk of MI relative to patients on placebo

RR = 1.45 means the risk in the exposed group is 1.45 times (45% higher than) the risk in the unexposed group.

A nurse needs to infuse 1 liter of normal saline over 8 hours using a standard IV drip set (20 drops/mL). What is the drip rate in drops per minute?

Answer: 42 drops/min

Total drops = 1000 mL × 20 drops/mL = 20,000 drops. Time = 8 h × 60 min = 480 min. Rate = 20,000 / 480 ≈ 41.7 ≈ 42 drops/min.

A study shows Disease Y has an incidence of 12 per 100,000 per year in the general population. A clinician sees 2,000 patients per year. How many new cases of Disease Y would be expected in her practice per year?

Answer: 0.24 cases per year (approximately 1 case every 4 years)

Expected cases = (12/100,000) × 2,000 = 0.24 cases per year — approximately one case every 4 years.

A patient's creatinine clearance is 45 mL/min. A drug's recommended dose adjustment states: 'Reduce dose by 50% if CrCl is between 30–59 mL/min.' The standard dose is 400 mg twice daily. What is the adjusted regimen?

Answer: 200 mg twice daily

50% dose reduction: 400 mg × 0.50 = 200 mg. Frequency (twice daily) is not changed by the instruction. Adjusted dose = 200 mg twice daily.

A patient's hemoglobin dropped from 12.4 g/dL to 9.8 g/dL over 2 weeks. The percent decline is approximately:

Answer: 21% decline

Percent change = (12.4 - 9.8) / 12.4 × 100 = 2.6 / 12.4 × 100 = 21%.