NPE cheat sheet

Sensitivity = TP/(TP+FN): probability a diseased patient tests positive; high sensitivity supports ruling out disease when the test is negative.

Specificity = TN/(TN+FP): probability a nondiseased patient tests negative; high specificity supports ruling in disease when the test is positive.

Positive likelihood ratio = sensitivity/(1 − specificity); values above 10 meaningfully shift pretest to posttest probability.

Negative likelihood ratio = (1 − sensitivity)/specificity; values below 0.1 meaningfully lower posttest probability.

Posttest odds = pretest odds × likelihood ratio; convert probability to odds (p/(1−p)) before applying the ratio.

Number needed to screen = 1/absolute risk reduction; NNS of 500 means 500 patients must be screened to prevent one outcome.

Murmur grading I–VI: grade I is barely audible, grade III is moderately loud, grade IV has a palpable thrill, and grade V is audible with the stethoscope partly off the chest.

Systolic murmurs that increase with Valsalva or standing (decreased preload) suggest hypertrophic cardiomyopathy; murmurs that increase with squatting or handgrip suggest aortic stenosis or mitral regurgitation.

Normal adult resting ankle-brachial index is 1.0–1.4; an ABI of 0.90 or less supports peripheral arterial disease and 1.4 or more suggests noncompressible vessels.

Volume of distribution = amount of drug in body / plasma concentration; large Vd (>1 L/kg) indicates extensive tissue distribution and poor dialysis removal.

Clearance = (rate of elimination)/plasma concentration; maintenance dose rate = clearance × target concentration.

Loading dose = (Vd × target concentration)/bioavailability; loading dose is independent of clearance.

Half-life ≈ 0.693 × Vd/clearance; steady state is reached after roughly 4–5 half-lives.

Cytochrome P450 inducers include rifampin, carbamazepine, phenytoin, and St. John's wort; inhibitors include azole antifungals, macrolides, and grapefruit.

Warfarin inhibits vitamin K epoxide reductase; effects are monitored with INR and reversed with vitamin K or prothrombin complex concentrate.

Metformin carries a boxed warning for lactic acidosis and is held before iodinated contrast when renal function is impaired.

Angiotensin-converting enzyme inhibitors cause cough and hyperkalemia and are contraindicated in pregnancy; angiotensin receptor blockers share the pregnancy contraindication without the cough.

Acetaminophen maximum adult dose is 4 g/day; in chronic alcohol use or hepatic impairment, limit to 2 g/day.

USPSTF colorectal cancer screening: adults aged 45–75 (grade A for 50–75, grade B for 45–49); screening options include colonoscopy every 10 years or annual fecal immunochemical testing.

Cervical cancer screening: start at age 21 with cytology every 3 years; ages 30–65 may use cytology every 3 years, HPV testing every 5 years, or co-testing every 5 years.

Mammography: biennial screening for women aged 50–74 is grade B; the decision for ages 40–49 is individualized (grade C).

Lung cancer screening with low-dose CT is recommended annually for adults aged 50–80 with a 20 pack-year history who currently smoke or quit within 15 years.

Adult tetanus-diphtheria booster every 10 years; Tdap once if not previously received, and in every pregnancy at 27–36 weeks.

Pneumococcal vaccination: adults 65 and older, and adults 19–64 with risk conditions, should receive PCV followed by PPSV23 per current schedule.

Hepatitis B vaccination is recommended for all adults aged 19–59 and for adults 60 and older with risk factors.

Five A's for behavior change: Ask, Advise, Assess, Assist, Arrange; motivational interviewing uses open questions, affirmations, reflections, and summaries.

Teach-back confirms comprehension by asking the patient to restate instructions in their own words; it is more reliable than asking whether the patient understands.

Ottawa ankle rules: obtain radiography if there is pain in the malleolar zone plus bone tenderness at the posterior malleolus or navicular, or inability to bear weight four steps.

Centor/McIsaac criteria (fever, tonsillar exudate, tender anterior cervical nodes, absence of cough) guide streptococcal testing; testing is not indicated with a score of 0–1.

Acute bacterial rhinosinusitis requires symptoms lasting 10 days or more, worsening after initial improvement, or severe symptoms with fever of 39°C or higher for 3–4 days.

Uncomplicated cystitis in women is treated with nitrofurantoin 5 days, trimethoprim-sulfamethoxazole 3 days (if local resistance under 20%), or fosfomycin as a single dose.

Asthma exacerbation severity: peak flow 40–69% of personal best indicates moderate exacerbation; below 40% indicates severe exacerbation.

Community-acquired pneumonia severity can be stratified with CURB-65 (confusion, urea above 7 mmol/L, respiratory rate 30 or more, blood pressure low, age 65 or older).

Acute gout is treated with NSAIDs, colchicine, or glucocorticoids; urate-lowering therapy is not started or adjusted during an acute flare.

Head trauma: obtain CT per Canadian CT Head Rule for loss of consciousness, vomiting, age 65 or older, amnesia, or dangerous mechanism.

Hypertension: stage 1 is 130–139/80–89 mmHg and stage 2 is 140/90 mmHg or higher; first-line agents are thiazide diuretics, ACE inhibitors/ARBs, and calcium channel blockers.

Type 2 diabetes: A1c target is below 7% for most adults; SGLT2 inhibitors or GLP-1 receptor agonists are preferred with atherosclerotic cardiovascular disease, heart failure, or chronic kidney disease.

Metabolic syndrome requires three of five: waist circumference threshold, triglycerides 150 mg/dL or higher, HDL below 40 (men) or 50 (women) mg/dL, blood pressure 130/85 or higher, fasting glucose 100 mg/dL or higher.

Heart failure with reduced ejection fraction: guideline-directed therapy includes an ARNI/ACE inhibitor/ARB, evidence-based beta blocker, mineralocorticoid receptor antagonist, and SGLT2 inhibitor.

Chronic kidney disease is staged by GFR: G1 90 or higher, G2 60–89, G3a 45–59, G3b 30–44, G4 15–29, G5 below 15 mL/min/1.73 m².

COPD is confirmed by post-bronchodilator FEV1/FVC below 0.70; GOLD airflow limitation grades use FEV1 percent predicted (GOLD 1: 80 or higher; GOLD 4: below 30).

Osteoporosis is defined by T-score of −2.5 or lower; treatment thresholds and fracture risk tools (FRAX) guide pharmacotherapy with bisphosphonates.

Lipid management: statin intensity is high (atorvastatin 40–80 mg, rosuvastatin 20–40 mg), moderate, or low; ASCVD risk estimates guide initiation.

Informed consent requires capacity, disclosure of material risks and alternatives, comprehension, and voluntariness; it is a process, not a signature.

Four ethical principles: autonomy, beneficence, nonmaleficence, and justice; autonomy generally governs competent adult decisions even when refusal risks harm.

A minor may consent to care for sexually transmitted infections, contraception, and prenatal care in many jurisdictions; status laws vary by state.

Mandatory reporting duties commonly include suspected child abuse, elder abuse, and certain communicable diseases; reporting is legally required even without patient consent.

HIPAA permits disclosure without authorization for treatment, payment, and operations, and for serious threats to health or safety under specific conditions.

Good Samaritan statutes protect clinicians providing emergency care outside their typical duty, absent gross negligence; they do not create a duty to rescue.

Negligence elements: duty, breach of the standard of care, causation, and damages; all four must be established.

Scope of practice is defined by state nurse practice acts; prescriptive authority, including controlled substances, requires DEA registration and state licensure.

Documentation should be contemporaneous, objective, and complete; alterations must be addended, never erased, to preserve the legal record.

Medicare Part A covers inpatient hospital, skilled nursing, hospice, and some home health; Part B covers outpatient services and durable medical equipment.

Medicare Part D covers outpatient prescription drugs; the Inflation Reduction Act caps out-of-pocket insulin at $35 per month and adds an annual out-of-pocket cap.

Medicaid is jointly funded by federal and state governments with state-administered eligibility and benefits; expansion status varies by state.

The Affordable Care Act requires coverage of preventive services graded A or B by USPSTF without cost sharing, and prohibits denial for preexisting conditions.

Accountable care organizations accept shared savings or risk for a defined population; quality metrics and total cost of care determine shared savings.

Care coordination models include the patient-centered medical home, transitional care management, and chronic care management, each with distinct billing codes.

Health insurance terms: deductible is out-of-pocket spending before coverage begins; coinsurance is a percentage of cost; copayment is a fixed amount.

Social determinants of health include income, housing, food security, transportation, and education; screening for these is increasingly a quality measure.

Incidence = new cases / population at risk per time period; prevalence = all existing cases / total population at a point or over a period.

Attack rate = new cases / population at risk during an outbreak; case fatality rate = deaths from disease / diagnosed cases.

Relative risk = incidence in exposed / incidence in unexposed; attributable risk = incidence in exposed − incidence in unexposed.

Herd immunity threshold ≈ 1 − 1/R0; measles R0 of 12–18 requires roughly 92–95% or higher population immunity.

Screening test performance depends on prevalence: positive predictive value falls as prevalence decreases, even with fixed sensitivity and specificity.

Culturally competent care includes self-awareness, knowledge of the patient's culture, and skills in cross-cultural communication, often using trained interpreters.

Social determinants of health account for a substantial share of health outcomes; screening tools include food insecurity, housing instability, and transportation barriers.

Health literacy affects medication adherence and self-management; universal precautions include plain language, teach-back, and written materials at a 5th–6th grade reading level.

Screening programs for populations should prioritize conditions that are common, treatable, detectable early, and have acceptable tests, per Wilson and Jungner criteria.

Sensitivity = TP/(TP+FN): probability a diseased patient tests positive; high sensitivity supports ruling out disease when the test is negative.

Specificity = TN/(TN+FP): probability a nondiseased patient tests negative; high specificity supports ruling in disease when the test is positive.

Positive likelihood ratio = sensitivity/(1 − specificity); values above 10 meaningfully shift pretest to posttest probability.

Negative likelihood ratio = (1 − sensitivity)/specificity; values below 0.1 meaningfully lower posttest probability.

Posttest odds = pretest odds × likelihood ratio; convert probability to odds (p/(1−p)) before applying the ratio.

Number needed to screen = 1/absolute risk reduction; NNS of 500 means 500 patients must be screened to prevent one outcome.

Murmur grading I–VI: grade I is barely audible, grade III is moderately loud, grade IV has a palpable thrill, and grade V is audible with the stethoscope partly off the chest.

Systolic murmurs that increase with Valsalva or standing (decreased preload) suggest hypertrophic cardiomyopathy; murmurs that increase with squatting or handgrip suggest aortic stenosis or mitral regurgitation.

Normal adult resting ankle-brachial index is 1.0–1.4; an ABI of 0.90 or less supports peripheral arterial disease and 1.4 or more suggests noncompressible vessels.

Volume of distribution = amount of drug in body / plasma concentration; large Vd (>1 L/kg) indicates extensive tissue distribution and poor dialysis removal.

Clearance = (rate of elimination)/plasma concentration; maintenance dose rate = clearance × target concentration.

Loading dose = (Vd × target concentration)/bioavailability; loading dose is independent of clearance.

Half-life ≈ 0.693 × Vd/clearance; steady state is reached after roughly 4–5 half-lives.

Cytochrome P450 inducers include rifampin, carbamazepine, phenytoin, and St. John's wort; inhibitors include azole antifungals, macrolides, and grapefruit.

Warfarin inhibits vitamin K epoxide reductase; effects are monitored with INR and reversed with vitamin K or prothrombin complex concentrate.

Metformin carries a boxed warning for lactic acidosis and is held before iodinated contrast when renal function is impaired.

Angiotensin-converting enzyme inhibitors cause cough and hyperkalemia and are contraindicated in pregnancy; angiotensin receptor blockers share the pregnancy contraindication without the cough.

Acetaminophen maximum adult dose is 4 g/day; in chronic alcohol use or hepatic impairment, limit to 2 g/day.

USPSTF colorectal cancer screening: adults aged 45–75 (grade A for 50–75, grade B for 45–49); screening options include colonoscopy every 10 years or annual fecal immunochemical testing.

Cervical cancer screening: start at age 21 with cytology every 3 years; ages 30–65 may use cytology every 3 years, HPV testing every 5 years, or co-testing every 5 years.

Mammography: biennial screening for women aged 50–74 is grade B; the decision for ages 40–49 is individualized (grade C).

Lung cancer screening with low-dose CT is recommended annually for adults aged 50–80 with a 20 pack-year history who currently smoke or quit within 15 years.

Adult tetanus-diphtheria booster every 10 years; Tdap once if not previously received, and in every pregnancy at 27–36 weeks.

Pneumococcal vaccination: adults 65 and older, and adults 19–64 with risk conditions, should receive PCV followed by PPSV23 per current schedule.

Hepatitis B vaccination is recommended for all adults aged 19–59 and for adults 60 and older with risk factors.

Five A's for behavior change: Ask, Advise, Assess, Assist, Arrange; motivational interviewing uses open questions, affirmations, reflections, and summaries.

Teach-back confirms comprehension by asking the patient to restate instructions in their own words; it is more reliable than asking whether the patient understands.

Ottawa ankle rules: obtain radiography if there is pain in the malleolar zone plus bone tenderness at the posterior malleolus or navicular, or inability to bear weight four steps.

Centor/McIsaac criteria (fever, tonsillar exudate, tender anterior cervical nodes, absence of cough) guide streptococcal testing; testing is not indicated with a score of 0–1.

Acute bacterial rhinosinusitis requires symptoms lasting 10 days or more, worsening after initial improvement, or severe symptoms with fever of 39°C or higher for 3–4 days.

Uncomplicated cystitis in women is treated with nitrofurantoin 5 days, trimethoprim-sulfamethoxazole 3 days (if local resistance under 20%), or fosfomycin as a single dose.

Asthma exacerbation severity: peak flow 40–69% of personal best indicates moderate exacerbation; below 40% indicates severe exacerbation.

Community-acquired pneumonia severity can be stratified with CURB-65 (confusion, urea above 7 mmol/L, respiratory rate 30 or more, blood pressure low, age 65 or older).

Acute gout is treated with NSAIDs, colchicine, or glucocorticoids; urate-lowering therapy is not started or adjusted during an acute flare.

Head trauma: obtain CT per Canadian CT Head Rule for loss of consciousness, vomiting, age 65 or older, amnesia, or dangerous mechanism.

Hypertension: stage 1 is 130–139/80–89 mmHg and stage 2 is 140/90 mmHg or higher; first-line agents are thiazide diuretics, ACE inhibitors/ARBs, and calcium channel blockers.

Type 2 diabetes: A1c target is below 7% for most adults; SGLT2 inhibitors or GLP-1 receptor agonists are preferred with atherosclerotic cardiovascular disease, heart failure, or chronic kidney disease.

Metabolic syndrome requires three of five: waist circumference threshold, triglycerides 150 mg/dL or higher, HDL below 40 (men) or 50 (women) mg/dL, blood pressure 130/85 or higher, fasting glucose 100 mg/dL or higher.

Heart failure with reduced ejection fraction: guideline-directed therapy includes an ARNI/ACE inhibitor/ARB, evidence-based beta blocker, mineralocorticoid receptor antagonist, and SGLT2 inhibitor.

Chronic kidney disease is staged by GFR: G1 90 or higher, G2 60–89, G3a 45–59, G3b 30–44, G4 15–29, G5 below 15 mL/min/1.73 m².

COPD is confirmed by post-bronchodilator FEV1/FVC below 0.70; GOLD airflow limitation grades use FEV1 percent predicted (GOLD 1: 80 or higher; GOLD 4: below 30).

Osteoporosis is defined by T-score of −2.5 or lower; treatment thresholds and fracture risk tools (FRAX) guide pharmacotherapy with bisphosphonates.

Lipid management: statin intensity is high (atorvastatin 40–80 mg, rosuvastatin 20–40 mg), moderate, or low; ASCVD risk estimates guide initiation.

Informed consent requires capacity, disclosure of material risks and alternatives, comprehension, and voluntariness; it is a process, not a signature.

Four ethical principles: autonomy, beneficence, nonmaleficence, and justice; autonomy generally governs competent adult decisions even when refusal risks harm.

A minor may consent to care for sexually transmitted infections, contraception, and prenatal care in many jurisdictions; status laws vary by state.

Mandatory reporting duties commonly include suspected child abuse, elder abuse, and certain communicable diseases; reporting is legally required even without patient consent.

HIPAA permits disclosure without authorization for treatment, payment, and operations, and for serious threats to health or safety under specific conditions.

Good Samaritan statutes protect clinicians providing emergency care outside their typical duty, absent gross negligence; they do not create a duty to rescue.

Negligence elements: duty, breach of the standard of care, causation, and damages; all four must be established.

Scope of practice is defined by state nurse practice acts; prescriptive authority, including controlled substances, requires DEA registration and state licensure.

Documentation should be contemporaneous, objective, and complete; alterations must be addended, never erased, to preserve the legal record.

Medicare Part A covers inpatient hospital, skilled nursing, hospice, and some home health; Part B covers outpatient services and durable medical equipment.

Medicare Part D covers outpatient prescription drugs; the Inflation Reduction Act caps out-of-pocket insulin at $35 per month and adds an annual out-of-pocket cap.

Medicaid is jointly funded by federal and state governments with state-administered eligibility and benefits; expansion status varies by state.

The Affordable Care Act requires coverage of preventive services graded A or B by USPSTF without cost sharing, and prohibits denial for preexisting conditions.

Accountable care organizations accept shared savings or risk for a defined population; quality metrics and total cost of care determine shared savings.

Care coordination models include the patient-centered medical home, transitional care management, and chronic care management, each with distinct billing codes.

Health insurance terms: deductible is out-of-pocket spending before coverage begins; coinsurance is a percentage of cost; copayment is a fixed amount.

Social determinants of health include income, housing, food security, transportation, and education; screening for these is increasingly a quality measure.

Incidence = new cases / population at risk per time period; prevalence = all existing cases / total population at a point or over a period.

Attack rate = new cases / population at risk during an outbreak; case fatality rate = deaths from disease / diagnosed cases.

Relative risk = incidence in exposed / incidence in unexposed; attributable risk = incidence in exposed − incidence in unexposed.

Herd immunity threshold ≈ 1 − 1/R0; measles R0 of 12–18 requires roughly 92–95% or higher population immunity.

Screening test performance depends on prevalence: positive predictive value falls as prevalence decreases, even with fixed sensitivity and specificity.

Culturally competent care includes self-awareness, knowledge of the patient's culture, and skills in cross-cultural communication, often using trained interpreters.

Social determinants of health account for a substantial share of health outcomes; screening tools include food insecurity, housing instability, and transportation barriers.

Health literacy affects medication adherence and self-management; universal precautions include plain language, teach-back, and written materials at a 5th–6th grade reading level.

Screening programs for populations should prioritize conditions that are common, treatable, detectable early, and have acceptable tests, per Wilson and Jungner criteria.