Body Surface Area of 1.86 m²: Clinical Interpretation
A BSA of 1.86 m² falls within the normal range for adults and represents the body surface area of an average-sized female adult in the United States. 1
Normal BSA Reference Values
- Average adult female BSA: 1.86 m² (based on mean weight 77.5 kg and mean height 161.3 cm using the Mosteller formula) 1
- Average adult male BSA: 2.1 m² (based on mean weight 90.6 kg and mean height 175.3 cm) 1
- Overall adult BSA range: Typically 1.73-2.04 m² depending on sex and body habitus 2, 3
Clinical Significance and Applications
Medication Dosing Context
- BSA is particularly critical for chemotherapeutic agents and other medications with narrow therapeutic indices, where accurate dosing based on body size is essential 4
- A BSA of 1.86 m² would be used to calculate weight-based and BSA-indexed drug doses, particularly for cancer treatments 1
Cardiovascular Parameter Indexing
- Cardiac measurements should be indexed to BSA for accurate assessment, especially in patients at the lower end of normal body size distribution 1, 5
- For aortic measurements, indexing to BSA is recommended to avoid underestimation of pathology, particularly in women and smaller patients 1
- An ascending thoracic aorta >22 mm/m² BSA or descending thoracic aorta >16 mm/m² BSA indicates aortic dilatation 1
Gender-Specific Considerations
- Women have systematically lower BSA than men, which has important implications for cardiovascular surgery thresholds 1
- Absolute left ventricular size criteria validated in men may lead to delayed intervention in women because their lower BSA means greater relative cardiac chamber dilatation when absolute thresholds are reached 1
- For aortic regurgitation, left ventricular end-systolic diameter >25 mm/m² BSA is a more appropriate surgical threshold than absolute measurements, particularly for patients with smaller body size 1
Calculation Methods
The Mosteller formula is widely used for its simplicity: BSA (m²) = √[(height in cm × weight in kg)/3600] 1, 2
Alternative formulas exist (DuBois, Gehan-George, Boyd), with excellent correlation (r >0.97) between methods, though the DuBois formula may underestimate BSA in obese patients by 3-5% 2
Clinical Pitfalls to Avoid
- Do not apply absolute measurement thresholds without considering BSA, especially in cardiovascular disease management in women and smaller patients 1
- BSA calculations may need adjustment in special populations including amputees and malnourished patients 4
- In extremes of body weight (very low or very high), BSA indexing has limitations, and alternative indexing methods (height, aortic length) may be more appropriate 1