Our Methodology

Formula: eAG (mg/dL) = 28.7 × A1c - 46.7

Source: Nathan DM, et al. "Translating the A1c assay into estimated average glucose values." Diabetes Care. 2008;31(8):1473-1478.

Validation: Based on the ADAG study with 507 subjects including type 1, type 2, and non-diabetic participants. Strong correlation (r=0.92) between A1c and average glucose from continuous monitoring.

Limitations: Assumes normal red blood cell turnover. May be less accurate in conditions affecting RBC lifespan (hemolytic anemia, chronic kidney disease, recent blood transfusions).

Classification: Based on 2017 ACC/AHA High Blood Pressure Guidelines

Source: Whelton PK, et al. "2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults." Hypertension. 2018;71(6):e13-e115.

Validation: Guidelines based on comprehensive review of evidence including SPRINT trial and meta-analyses of cardiovascular outcomes.

Use Case: For adults ≥18 years. Requires proper measurement technique (seated, rested, correct cuff size). Single readings should be confirmed on multiple occasions.

Formula: CrCl = [(140 - age) × weight (kg)] / [72 × SCr (mg/dL)] × (0.85 if female)

Source: Cockcroft DW, Gault MH. "Prediction of creatinine clearance from serum creatinine." Nephron. 1976;16(1):31-41.

Validation: Validated extensively for medication dosing adjustments. Widely used in clinical practice and drug labeling.

Limitations: Less accurate at extremes of body weight, in elderly patients, and in rapid changes in kidney function. Uses actual body weight, not ideal body weight. For GFR estimation, MDRD or CKD-EPI equations may be preferred.

Formula: Remaining amount = Initial dose × (0.5)^(time elapsed / half-life)

Principle: First-order kinetics - after each half-life, 50% of the medication is eliminated

Source: Standard pharmacokinetic principles from clinical pharmacology textbooks and drug labeling information

Validation: Half-life values are obtained from FDA-approved drug labels and peer-reviewed pharmacokinetic studies

Limitations: Assumes first-order elimination kinetics. Actual half-life varies by individual based on age, kidney/liver function, drug interactions, and genetics. Provides population averages, not individual predictions.

Formula: Maximum Heart Rate = 220 - age; Target zones = % of max HR

Source: Based on American Heart Association recommendations for target heart rate during exercise

Validation: Age-predicted maximum heart rate formula validated in large population studies. Zone percentages align with metabolic and cardiovascular training effects.

Limitations: Maximum heart rate prediction has standard deviation of ±10-12 bpm. Individual variation exists based on fitness level and genetics. Not applicable to individuals on heart rate-modifying medications (beta-blockers, calcium channel blockers).

Formula: GMI (%) = 3.31 + (0.02392 × average glucose in mg/dL)

Source: Bergenstal RM, et al. "Glucose Management Indicator (GMI): A New Term for Estimating A1C From Continuous Glucose Monitoring." Diabetes Care. 2018;41(11):2275-2280.

Validation: Developed from data analyzing relationship between CGM average glucose and laboratory A1c in >2,000 CGM users

Limitations: GMI is an estimate and may differ from lab A1c by ±0.5% or more. Differences can occur due to red blood cell turnover variations, time lag between glucose exposure and hemoglobin glycation, and CGM accuracy.

Basis: Projections based on clinical trial data showing average weight loss trajectories

Source: STEP clinical trial program and SUSTAIN trials for semaglutide weight loss outcomes

Validation: Uses population-average weight loss percentages observed in phase 3 clinical trials over 68 weeks

Limitations: Individual results vary significantly. Projections are estimates based on clinical trial averages. Actual weight loss depends on dose, adherence, diet, exercise, genetics, and metabolic factors. Not predictive of individual outcomes.

Basis: Timing recommendations based on circadian rhythm research and cortisol secretion patterns

Source: Circadian biology literature on cortisol awakening response and optimal timing for light exposure, caffeine, and sleep

Validation: Based on established patterns of cortisol peaks (30-45 min post-waking), adenosine clearance timing, and circadian phase regulation

Limitations: Recommendations are population averages. Individual chronotypes (early birds vs. night owls), age, and circadian disorders affect optimal timing. Not medical treatment for sleep disorders.

Formula: Drip rate (drops/min) = (Volume in mL × Drop factor) / Time in minutes

Source: Standard nursing calculation principles from infusion therapy guidelines

Validation: Fundamental fluid mechanics calculation used universally in nursing practice

Limitations: Manual drip rates are less precise than infusion pumps. Rate can drift due to gravity changes, tubing position, and patient movement. Requires hourly monitoring. Not appropriate for high-risk medications requiring precise control.

Formula: Naegele's Rule: EDD = LMP + 280 days (or LMP + 1 year - 3 months + 7 days)

Source: Franz Karl Naegele (1778-1851); validated in ACOG Committee Opinion guidelines

Validation: Standard obstetric calculation used worldwide for over 200 years. Assumes 28-day cycle with ovulation on day 14.

Limitations: Assumes regular 28-day cycles. Less accurate with irregular cycles. First trimester ultrasound is more accurate for dating if LMP uncertain. Actual delivery occurs within 2 weeks of EDD in ~80% of pregnancies.

Formula: CKD-EPI 2021 race-free equation: GFR = 142 × min(SCr/κ, 1)^α × max(SCr/κ, 1)^-1.200 × 0.9938^Age × (1.012 if female)

Source: Inker LA, et al. "New Creatinine- and Cystatin C-Based Equations to Estimate GFR without Race." N Engl J Med. 2021;385(19):1737-1749.

Validation: Developed from pooled data of 10 studies with >12,000 participants. Eliminates race coefficient while maintaining accuracy.

Limitations: Less accurate at extremes of body size, in acute kidney injury, pregnancy, and with certain diets. Creatinine-based estimates affected by muscle mass. CKD staging should incorporate albuminuria.

Formula: Pooled Cohort Equations using sex-specific coefficients for age, cholesterol, HDL, blood pressure, diabetes, and smoking status

Source: Goff DC Jr, et al. "2013 ACC/AHA Guideline on the Assessment of Cardiovascular Risk." Circulation. 2014;129(25 Suppl 2):S49-73.

Validation: Derived from multiple large cohort studies (ARIC, CHS, CARDIA, Framingham). Validated for 10-year ASCVD risk prediction in adults 40-79 years.

Limitations: May overestimate risk in some populations. Less validated in ethnic groups other than white and Black Americans. Does not account for family history, inflammatory markers, or coronary calcium score.

Basis: Morphine milligram equivalents (MME) using CDC and CMS conversion factors

Source: CDC Opioid Prescribing Guidelines (2022); CMS Opioid Morphine Equivalent Conversion Factors

Validation: Conversion factors based on clinical pharmacology studies and consensus guidelines. Widely adopted in clinical practice and regulatory frameworks.

Limitations: Cross-tolerance is incomplete - reduce dose 25-50% when switching opioids. Individual variation in metabolism (CYP2D6 polymorphisms). Methadone and fentanyl have non-linear conversions. Should not replace clinical judgment in complex cases.

Basis: Glucocorticoid equivalencies based on anti-inflammatory potency ratios relative to hydrocortisone

Source: Clinical pharmacology literature; standard equivalency tables from endocrinology and rheumatology guidelines

Validation: Equivalencies established through decades of clinical use. Standard reference: hydrocortisone 20mg = prednisone 5mg = methylprednisolone 4mg = dexamethasone 0.75mg.

Limitations: Equivalencies are for anti-inflammatory effect only. Mineralocorticoid activity varies between steroids. Duration of action differs. Does not account for individual pharmacokinetic variation or adrenal suppression recovery.

Formulas: Katz: Corrected Na = Measured Na + 1.6 × [(Glucose - 100) / 100]; Hillier: Corrected Na = Measured Na + 2.4 × [(Glucose - 100) / 100]

Source: Katz MA. Hyperglycemia-induced hyponatremia. N Engl J Med. 1973;289:843-844; Hillier TA et al. Hyponatremia: evaluating the correction factor. Am J Med. 1999;106:399-403.

Validation: Katz formula (1.6 factor) widely used; Hillier formula (2.4 factor) may be more accurate at very high glucose levels.

Limitations: Applies only to hyperglycemia-induced hyponatremia (DKA, HHS). Not applicable to other causes of hyponatremia. Linear correction may be less accurate at extreme glucose values.

Basis: Weight-based dosing (mg/kg) with maximum dose limits from pediatric formularies

Source: Harriet Lane Handbook; Pediatric Dosage Handbook (Lexicomp); FDA-approved pediatric labeling

Validation: Doses derived from pharmacokinetic studies in pediatric populations and established clinical practice guidelines.

Limitations: Age-specific considerations not always captured. Neonates and infants may require different dosing. Renal/hepatic function affects dosing. Always verify against current drug references and institutional protocols. Maximum doses should not exceed adult doses.

Scoring: CHF (1), Hypertension (1), Age ≥75 (2), Diabetes (1), Stroke/TIA (2), Vascular disease (1), Age 65-74 (1), Sex female (1)

Source: Lip GY, et al. "Refining clinical risk stratification for predicting stroke and thromboembolism in atrial fibrillation." Chest. 2010;137(2):263-272.

Validation: Validated in multiple cohorts for predicting stroke risk in non-valvular atrial fibrillation. Endorsed by ACC/AHA/ESC guidelines.

Limitations: Designed for non-valvular AF only. Does not apply to valvular AF (mechanical valves, mitral stenosis). Risk stratification guides anticoagulation decisions but does not account for bleeding risk (use HAS-BLED separately).

Formula: MELD = 3.78 × ln(bilirubin) + 11.2 × ln(INR) + 9.57 × ln(creatinine) + 6.43; MELD-Na adds sodium correction

Source: Kamath PS, et al. "A model to predict survival in patients with end-stage liver disease." Hepatology. 2001;33(2):464-470; MELD-Na: Kim WR, et al. Hepatology. 2008.

Validation: Extensively validated for predicting 90-day mortality in cirrhosis. Used by UNOS for liver transplant allocation since 2002.

Limitations: Lab values must be from same draw. Creatinine capped at 4.0, set to 4.0 if on dialysis. Does not capture all disease severity (HCC, hepatopulmonary syndrome). MELD-Na more accurate with hyponatremia.

Basis: Clinical decision rules using weighted criteria to estimate pretest probability of venous thromboembolism

Source: Wells PS, et al. "Derivation of a simple clinical model to categorize patients probability of pulmonary embolism." Thromb Haemost. 2000; Wells PS, et al. "Value of assessment of pretest probability of deep-vein thrombosis." Lancet. 1997.

Validation: Extensively validated in emergency department and outpatient settings. Used in combination with D-dimer to guide imaging decisions.

Limitations: Designed for ambulatory patients. Less validated in hospitalized, pregnant, or post-surgical patients. Should be used with D-dimer testing. Low probability does not exclude VTE - guides need for further testing.

Formula: Corrected Ca = Measured Ca + 0.8 × (4.0 - Albumin)

Source: Payne RB, et al. "Interpretation of serum calcium in patients with abnormal serum proteins." Br Med J. 1973;4(5893):643-646.

Validation: Standard correction used clinically for decades. Accounts for approximately 45% of total calcium being protein-bound.

Limitations: Correction factor (0.8) is an approximation. Less accurate with severe hypoalbuminemia, abnormal pH, or high/low globulins. Ionized calcium is the gold standard when available. Does not correct for other binding proteins.