Avoiding unnecessary testing US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Avoiding unnecessary testing. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Avoiding unnecessary testing US Medical PG Question 1: A mother presents to the family physician with her 16-year-old son. She explains, "There's something wrong with him doc. His grades are getting worse, he's cutting class, he's gaining weight, and his eyes are often bloodshot." Upon interviewing the patient apart from his mother, he seems withdrawn and angry at times when probed about his social history. The patient denies abuse and sexual history. What initial test should be sent to rule out the most likely culprit of this patient's behavior?
- A. Complete blood count
- B. Sexually transmitted infection (STI) testing
- C. Blood culture
- D. Urine toxicology screen (Correct Answer)
- E. Slit lamp examination
Avoiding unnecessary testing Explanation: ***Urine toxicology screen***
- The patient's presentation with **declining grades**, **cutting class**, **weight gain**, **bloodshot eyes**, and **irritability** are classic signs of **substance abuse** in an adolescent.
- A **urine toxicology screen** is the most appropriate initial test to detect common illicit substances, especially given the clear signs pointing towards drug use.
*Slit lamp examination*
- This test is used to examine the **anterior segment of the eye**, including the conjunctiva, cornea, iris, and lens.
- While the patient has **bloodshot eyes**, this specific test would be more relevant for ruling out ocular infections or injuries, not for diagnosing the underlying cause of systemic behavioral changes.
*Complete blood count*
- A **complete blood count (CBC)** measures different components of the blood, such as red blood cells, white blood cells, and platelets.
- A CBC is a general health indicator and while it can detect infections or anemia, it is not specific or sensitive enough to identify the cause of the behavioral changes described.
*Sexually transmitted infection (STI) testing*
- Although the patient denies sexual history, all adolescents presenting with certain risk factors or symptoms may warrant STI testing in a broader health assessment.
- However, in this scenario, the primary cluster of symptoms (poor grades, cutting class, bloodshot eyes, irritability) points more directly to substance abuse than to an STI.
*Blood culture*
- A **blood culture** is used to detect the presence of bacteria or other microorganisms in the bloodstream, indicating a systemic infection (sepsis).
- The patient's symptoms are not indicative of an acute bacterial bloodstream infection, and a blood culture would not be the initial test for the presented behavioral changes.
Avoiding unnecessary testing US Medical PG Question 2: A 70-year-old woman presents to the office for a yearly physical. She states she has recently started experiencing pain in her legs and her back. Last year, she experienced a fracture of her left arm while trying to lift groceries. The patient states that she does not consume any dairy and does not go outside often because of the pain in her legs and back. Of note, she takes carbamazepine for seizures. On exam, her vitals are within normal limits. You suspect the patient might have osteomalacia. Testing for which of the following is the next best step to confirm your suspicion?
- A. Vitamin D2 (ergocalciferol)
- B. 25-hydroxyvitamin D (Correct Answer)
- C. Pre-vitamin D3
- D. 1,25-hydroxyvitamin D
- E. 7-dehydrocholesterol
Avoiding unnecessary testing Explanation: ***25-hydroxyvitamin D***
- This is the **best initial test** for evaluating vitamin D deficiency, which leads to **osteomalacia**.
- It reflects the circulating levels of vitamin D and is the **most accurate indicator** of the body's vitamin D stores.
*Vitamin D2 (ergocalciferol)*
- While D2 is a form of vitamin D, measuring only D2 levels is **not sufficient** to assess overall vitamin D status.
- The standard test measures total circulating vitamin D, which includes both D2 and D3, but specifically **25-hydroxyvitamin D** reflects the active usable form.
*Pre-vitamin D3*
- **Pre-vitamin D3** is a precursor molecule formed in the skin from 7-dehydrocholesterol upon UV exposure, and it rapidly isomerizes to vitamin D3.
- It is **not a stable measurable form** in the blood for assessing vitamin D status or diagnosing osteomalacia.
*1,25-hydroxyvitamin D*
- This is the **active hormonal form of vitamin D**, primarily regulated by parathyroid hormone (PTH) and kidney function.
- Levels can be normal or even elevated in early vitamin D deficiency due to increased PTH, making it **less reliable** for initial assessment of deficiency.
*7-dehydrocholesterol*
- **7-dehydrocholesterol** is a precursor molecule in the skin that is converted to pre-vitamin D3 by UV radiation.
- Measuring this precursor is **not clinically significant** for diagnosing osteomalacia or assessing vitamin D deficiency.
Avoiding unnecessary testing US Medical PG Question 3: A 61-year-old Caucasian woman comes to the physician for a routine health maintenance examination. She feels well. She had a normal mammography 10 months ago and a normal serum lipid profile 3 years ago. Two years ago, a pap smear and testing for human papillomavirus were performed and were negative. She had a normal colonoscopy 6 years ago. HIV testing at that time was also negative. Her blood pressure and serum blood glucose were within normal limits during a routine visit 6 months ago. She is a retired university professor and lives together with her husband. She has no children. Menopause occurred 7 years ago. Her father developed colon cancer at the age of 75 years. She does not smoke or drink alcohol. Her only medication is a daily multivitamin. She is 163 cm (5 ft 4 in) tall and weighs 58 kg (128 lb); BMI is 22 kg/m2. Which of the following health maintenance recommendations is most appropriate at this time?
- A. Serum HIV testing
- B. Reassurance (Correct Answer)
- C. Colonoscopy
- D. Fecal occult blood test
- E. Dual-energy x-ray bone absorptiometry
Avoiding unnecessary testing Explanation: ***Reassurance***
- This patient's **preventive health screenings are up to date** based on current USPSTF guidelines for her age and risk profile.
- **Mammography** was performed 10 months ago (annual screening recommended, so technically due soon but not urgently overdue)
- **Colonoscopy** was 6 years ago with normal results; next screening at **10 years** (4 years remaining)
- **Pap smear with HPV co-testing** was 2 years ago; next screening at **5 years** (3 years remaining)
- **DEXA scan** is not yet indicated at age 61 without risk factors (screening starts at age **65** for average-risk women)
- No other urgent screening needs among the listed options make reassurance the most appropriate recommendation
*Dual-energy x-ray bone absorptiometry*
- **DEXA screening** for osteoporosis is recommended starting at age **65 years** for all women, or earlier (age 60-64) only for women with **increased risk factors**
- This patient is **61 years old** with **no osteoporosis risk factors**: normal BMI (22 kg/m²), no smoking, no alcohol use, no chronic steroid use, no family history of osteoporosis
- Screening at this time would be **premature** and not guideline-concordant
*Colonoscopy*
- Patient had a **normal colonoscopy 6 years ago**; repeat screening is recommended in **10 years** for average-risk individuals with normal results
- Her father developed colon cancer at age **75 years**, which does not meet criteria for high-risk family history (would need first-degree relative diagnosed before age 60)
- **4 years remain** before next colonoscopy is due
*Serum HIV testing*
- Patient had **negative HIV testing 6 years ago** with **no new risk factors** or high-risk behaviors
- She is in a stable relationship with her husband
- **Routine repeat HIV testing** is not indicated for low-risk individuals without new exposures
*Fecal occult blood test*
- Patient already has adequate colon cancer screening with **colonoscopy 6 years ago**
- FOBT would be **redundant** and is an inferior screening method compared to colonoscopy
- Next colon cancer screening not due for **4 more years**
Avoiding unnecessary testing US Medical PG Question 4: A 22-year-old man comes to the physician for a routine physical examination. He feels well. He has no history of major medical illness and takes no medications. His vital signs are within normal limits. Examination shows no abnormalities. Laboratory studies, including a complete blood count and a standard electrolyte panel, are within normal limits. Urine dipstick is negative for glucose; a reducing substance test result of the urine is positive. Which of the following is the most appropriate dietary recommendation for this patient?
- A. Eliminate galactose and lactose
- B. Eliminate fructose and sucrose
- C. Increase intake of ketogenic amino acids
- D. Decrease purine intake
- E. No changes needed (Correct Answer)
Avoiding unnecessary testing Explanation: ***No changes needed***
- The positive urine reducing substance test with negative urine glucose in an otherwise healthy individual often indicates **essential fructosuria**, a benign condition.
- Essential fructosuria is caused by a deficiency in **fructokinase** and does not require any dietary modifications.
*Eliminate galactose and lactose*
- This recommendation would be appropriate for **galactosemia**, a condition where the body cannot properly metabolize galactose.
- Galactosemia typically presents with more severe symptoms in infancy, such as **failure to thrive**, **jaundice**, and **cataracts**, which are not present here.
*Eliminate fructose and sucrose*
- This is the recommended diet for **hereditary fructose intolerance**, a more severe disorder involving a deficiency of **aldolase B**.
- Hereditary fructose intolerance would lead to symptoms like **hypoglycemia**, **vomiting**, and **liver damage** upon ingestion of fructose, which are absent in this case.
*Increase intake of ketogenic amino acids*
- This dietary approach is typically used for conditions like **pyruvate dehydrogenase complex deficiency** or **glucose transporter type 1 deficiency syndrome (Glut1 deficiency)**.
- These conditions involve metabolic crises or neurological symptoms that are not relevant to the patient's presentation.
*Decrease purine intake*
- A low-purine diet is recommended for conditions associated with **hyperuricemia**, such as **gout** or **Lesch-Nyhan syndrome**.
- There is no indication of elevated uric acid levels or symptoms related to purine metabolism in this patient.
Avoiding unnecessary testing US Medical PG Question 5: A 67-year-old woman presents with right leg pain and swelling of 5 days’ duration. She has a history of hypertension for 15 years and had a recent hospitalization for pneumonia. She had been recuperating at home but on beginning to mobilize and walk, the right leg became painful and swollen. Her temperature is 37.1°C (98.7°F), the blood pressure is 130/80 mm Hg, and the pulse is 75/min. On physical examination, the right calf is 4 cm greater in circumference than the left when measured 10 cm below the tibial tuberosity. Dilated superficial veins are present on the right foot and the right leg is slightly redder than the left. There is some tenderness on palpation in the popliteal fossa behind the knee. Which of the following is the best initial step in the management of this patient’s condition?
- A. International normalized ratio (INR)
- B. Thrombophilia screen
- C. Wells’ clinical probability tool (Correct Answer)
- D. Computerized tomography (CT) with contrast
- E. Activated partial thromboplastin time (aPTT)
Avoiding unnecessary testing Explanation: ***Wells' clinical probability tool***
- The patient presents with classic signs and symptoms of **deep vein thrombosis (DVT)**, including unilateral leg pain and swelling, dilated superficial veins, and tenderness. The Wells' clinical probability tool helps stratify the risk of DVT, guiding further diagnostic testing.
- Using this validated clinical decision rule for risk assessment is the **best initial step** to determine the likelihood of DVT before proceeding with imaging studies (compression ultrasound) or D-dimer testing.
- Based on the Wells' score, patients are categorized as low, moderate, or high probability, which then directs appropriate diagnostic testing and potential empiric anticoagulation.
*International normalized ratio (INR)*
- **INR** is used to monitor the effectiveness of **warfarin** therapy, an anticoagulant, and to assess liver function.
- It is not an initial diagnostic tool for DVT; rather, it is used **after a DVT diagnosis** has been made and anticoagulation with warfarin has been initiated.
*Thrombophilia screen*
- A **thrombophilia screen** investigates underlying genetic or acquired clotting disorders.
- This is typically performed **after a DVT diagnosis** in younger patients, those with recurrent DVT, or those with a family history of thrombosis, not as an initial diagnostic step unless there is strong suspicion for an underlying clotting disorder.
*Computerized tomography (CT) with contrast*
- A **CT with contrast** (specifically **CT venography**) can diagnose DVT, but it is not the **first-line imaging modality** for suspected DVT because of radiation exposure and contrast risks.
- **Compression ultrasonography** is generally the preferred initial imaging study for DVT, especially after a risk assessment using the Wells' score.
*Activated partial thromboplastin time (aPTT)*
- The **aPTT** is a measure of the intrinsic and common pathways of coagulation and is used to monitor **unfractionated heparin** therapy.
- It is not an initial diagnostic test for DVT; like INR, it is used **after diagnosis** for monitoring anticoagulant treatment.
Avoiding unnecessary testing US Medical PG Question 6: A 37-year-old woman presents to the Emergency Department after 8 hours of left sided flank pain that radiates to her groin and pelvic pain while urinating. Her medical history is relevant for multiple episodes of urinary tract infections, some requiring hospitalization, and intravenous antibiotics. In the hospital, her blood pressure is 125/83 mm Hg, pulse of 88/min, a respiratory rate of 28/min, and a body temperature of 36.5°C (97.7°F). On physical examination, she has left costovertebral tenderness and lower abdominal pain. Laboratory studies include a negative pregnancy test, mild azotemia, and a urinary dipstick that is positive for blood. Which of the following initial tests would be most useful in the diagnosis of this case?
- A. Urine osmolality
- B. Fractional excretion of sodium (FeNa+)
- C. Renal ultrasonography (Correct Answer)
- D. Contrast abdominal computed tomography
- E. Blood urea nitrogen (BUN): serum creatinine (SCr) ratio
Avoiding unnecessary testing Explanation: ***Renal ultrasonography***
- This is the most appropriate initial imaging test to evaluate for **kidney stones** (given the flank pain radiating to groin and hematuria) and **hydronephrosis** (which can indicate obstruction) and assess for signs of **pyelonephritis** (given the history of recurrent UTIs and CVA tenderness).
- It is **non-invasive**, readily available, and avoids radiation exposure, making it suitable as a first-line diagnostic tool in this setting.
*Urine osmolality*
- This test primarily assesses the kidney's ability to **concentrate urine**, which is more relevant for evaluating fluid balance, diabetes insipidus, or other renal tubular disorders.
- It would not directly diagnose the cause of acute flank pain or urinary tract obstruction.
*Fractional excretion of sodium (FeNa+)*
- FeNa+ is used to differentiate between **prerenal azotemia** and **acute tubular necrosis**, indicating the kidney's response to hypoperfusion.
- While the patient has mild azotemia, FeNa+ would not identify the underlying cause of the flank pain, hematuria, or potential obstruction.
*Contrast abdominal computed tomography*
- While highly sensitive for diagnosing kidney stones and other renal pathologies, **contrast CT** exposes the patient to **ionizing radiation** and risks associated with contrast agents (e.g., contrast-induced nephropathy), especially with pre-existing azotemia.
- It is often reserved for cases where ultrasound is inconclusive or more detailed anatomical information is needed.
*Blood urea nitrogen (BUN): serum creatinine (SCr) ratio*
- This ratio is primarily used to differentiate between **prerenal** causes of acute kidney injury (high ratio, e.g., >20:1) and **intrinsic renal** causes (lower ratio, e.g., <15:1).
- While it can provide insight into the etiology of azotemia, it does not directly identify the cause of the patient's acute flank pain or potential urinary tract obstruction.
Avoiding unnecessary testing US Medical PG Question 7: A student health coordinator plans on leading a campus-wide HIV screening program that will be free for the entire undergraduate student body. The goal is to capture as many correct HIV diagnoses as possible with the fewest false positives. The coordinator consults with the hospital to see which tests are available to use for this program. Test A has a sensitivity of 0.92 and a specificity of 0.99. Test B has a sensitivity of 0.95 and a specificity of 0.96. Test C has a sensitivity of 0.98 and a specificity of 0.93. Which of the following testing schemes should the coordinator pursue?
- A. Test A on the entire student body followed by Test B on those who are positive
- B. Test A on the entire student body followed by Test C on those who are positive
- C. Test C on the entire student body followed by Test B on those who are positive
- D. Test C on the entire student body followed by Test A on those who are positive (Correct Answer)
- E. Test B on the entire student body followed by Test A on those who are positive
Avoiding unnecessary testing Explanation: ***Test C on the entire student body followed by Test A on those who are positive***
- To "capture as many correct HIV diagnoses as possible" (maximize true positives), the initial screening test should have the **highest sensitivity**. Test C has the highest sensitivity (0.98).
- To "capture as few false positives as possible" (maximize true negatives and confirm diagnoses), the confirmatory test should have the **highest specificity**. Test A has the highest specificity (0.99).
*Test A on the entire student body followed by Test B on those who are positive*
- Starting with Test A (sensitivity 0.92) would miss more true positive cases than starting with Test C (sensitivity 0.98), failing the goal of **capturing as many cases as possible**.
- Following with Test B (specificity 0.96) would result in more false positives than following with Test A (specificity 0.99).
*Test A on the entire student body followed by Test C on those who are positive*
- This scheme would miss many true positive cases initially due to Test A's lower sensitivity compared to Test C.
- Following with Test C would introduce more false positives than necessary, as it has a lower specificity (0.93) than Test A (0.99).
*Test C on the entire student body followed by Test B on those who are positive*
- While Test C is a good initial screen for its high sensitivity, following it with Test B (specificity 0.96) is less optimal than Test A (specificity 0.99) for minimizing false positives in the confirmation step.
- This combination would therefore yield more false positives in the confirmatory stage than using Test A.
*Test B on the entire student body followed by Test A on those who are positive*
- Test B has a sensitivity of 0.95, which is lower than Test C's sensitivity of 0.98, meaning it would miss more true positive cases at the initial screening stage.
- While Test A provides excellent specificity for confirmation, the initial screening step is suboptimal for the goal of capturing as many diagnoses as possible.
Avoiding unnecessary testing US Medical PG Question 8: You submit a paper to a prestigious journal about the effects of coffee consumption on mesothelioma risk. The first reviewer lauds your clinical and scientific acumen, but expresses concern that your study does not have adequate statistical power. Statistical power refers to which of the following?
- A. The probability of detecting an association when no association exists.
- B. The probability of not detecting an association when an association does exist.
- C. The probability of detecting an association when an association does exist. (Correct Answer)
- D. The first derivative of work.
- E. The square root of the variance.
Avoiding unnecessary testing Explanation: ***The probability of detecting an association when an association does exist.***
- **Statistical power** is defined as the probability that a study will correctly reject a false null hypothesis, meaning it will detect a true effect or association if one exists.
- A study with **adequate statistical power** is less likely to miss a real effect.
*The probability of detecting an association when no association exists.*
- This describes a **Type I error** or **false positive**, often represented by **alpha (α)**.
- It is the probability of incorrectly concluding an effect or association exists when, in reality, there is none.
*The probability of not detecting an association when an association does exist.*
- This refers to a **Type II error** or **false negative**, represented by **beta (β)**.
- **Statistical power** is calculated as **1 - β**, so this option describes the complement of power.
*The first derivative of work.*
- The first derivative of work with respect to time represents **power** in physics, which is the rate at which work is done.
- This option is a **distractor** from physics and is unrelated to statistical power in research.
*The square root of the variance.*
- The **square root of the variance** is the **standard deviation**, a measure of the dispersion or spread of data.
- This is a statistical concept but is not the definition of statistical power.
Avoiding unnecessary testing US Medical PG Question 9: A 24-year-old African American college student comes to the office for a scheduled visit. He has been healthy, although he reports occasional flank discomfort which comes and goes. He denies any fever, chills, dysuria, or polyuria in the past year. His vaccinations are up to date. His family history is unknown, as he was adopted. He smokes 1 pack of cigarettes every 3 days, drinks socially, and denies any current illicit drug use, although he endorses a history of injection drug use. He currently works as a waiter to afford his college tuition. His physical examination shows a young man with a lean build, normal heart sounds, clear breath sounds, bowel sounds within normal limits, and no lower extremity edema. You order a urinalysis which shows 8 red blood cells (RBCs) per high-power field (HPF). The test is repeated several weeks later and shows 6 RBCs/HPF. What is the most appropriate next step in management?
- A. Plain abdominal X-ray
- B. Repeat urinalysis in 6 months
- C. 24-hour urine collection test
- D. Renal ultrasound (Correct Answer)
- E. Observation
Avoiding unnecessary testing Explanation: ***Renal ultrasound***
- This patient has **asymptomatic microscopic hematuria** which requires investigation to rule out significant renal or urological pathology, particularly in the context of recurrent flank discomfort and a history of injection drug use which increases risk for certain renal diseases.
- A **renal ultrasound** is the most appropriate initial imaging study to evaluate the kidneys and urinary tract for structural abnormalities, stones, masses, or hydronephrosis.
*Plain abdominal X-ray*
- A plain abdominal X-ray (KUB) is **less sensitive** than ultrasound for detecting many renal pathologies, especially soft tissue masses or early hydronephrosis.
- While it can detect **radio-opaque stones**, it will miss radiolucent stones and other important causes of hematuria.
*Repeat urinalysis in 6 months*
- This approach is too delayed given the **persistent microscopic hematuria** and the patient's reported flank discomfort, which warrants a more immediate workup.
- Delaying investigation could lead to the **progression of underlying pathology** that might be treatable if caught earlier.
*24-hour urine collection test*
- A 24-hour urine collection is useful for assessing **proteinuria** and **creatinine clearance**, and sometimes for quantification of red blood cell excretion, but it is not the initial diagnostic step for identifying the *source* or *cause* of hematuria.
- It would typically be considered **after initial imaging** and further characterization of the hematuria have been performed.
*Observation*
- **Observation alone is insufficient** for unexplained, persistent microscopic hematuria combined with flank discomfort, even if intermittent.
- This approach risks missing a potentially serious underlying condition that could benefit from early diagnosis and intervention, such as **renal cell carcinoma** or significant **nephrolithiasis**.
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