Body Surface Area (Du Bois) mechanism

Model scope

Du Bois and Mosteller formulas are correct under the stated kg/cm conventions. Verdict is NEEDS_REVIEW because the specification promises Haycock support without supplying its formula and leaves formula-selection behavior ambiguous.

• The Du Bois formula BSA=0.007184·W^0.425·H^0.725 is standard when W is in kg and H is in cm.
• The Mosteller formula BSA=√(H·W/3600) is standard when H is in cm and W is in kg.
• ios27_notes claims a Haycock formula toggle, but no Haycock formula is provided for verification or implementation. The standard Haycock form is approximately BSA=0.024265·H^0.3964·W^0.5378 with H in cm and W in kg.
• The formula-select input does not specify a default, accepted selector values, or behavior when the selector is missing or invalid.

Units and conventions

• Weight W must be provided in kilograms.
• Height H must be provided in centimeters; using height in meters without conversion produces an incorrect result.
• The constant 3600 in the Mosteller formula is valid for kilograms and centimeters and yields BSA in square meters.
• Both inputs must be finite, nonnegative numeric values for mathematical evaluation; clinical use should require strictly positive values.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "weight_kg": 70,
    "height_cm": 170,
    "formula_select": "Du Bois"
  },
  "expected_outputs": {
    "bsa_m2": 1.81
  },
  "working": "BSA=0.007184·70^0.425·170^0.725. 70^0.425≈6.0837. 170^0.725≈41.4071. 6.0837·41.4071≈251.907. 0.007184·251.907≈1.8097 m², which rounds to 1.810 m²."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The instrument reaches undefined NaN-like results for negative inputs, accepts a mathematically zero but physically invalid weight unless validation is added, and is vulnerable to materially different BSA values when kg/cm versus lb/in conventions are not explicit.

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche2/tranche2-results.json
• BOUNDARY_HAZARD_CATALOG.json