D007 检验与生命体征标准化

references/unit-conversion-policy.md

The default is no conversion.

A conversion may run only when all are true:

1. measurement identity is resolved to a key in the local measurement catalog;
2. raw unit resolves exactly to an allowlisted unit alias;
3. a conversion rule exists for (measurement, from_unit, preferred_unit);
4. the input is numeric and finite;
5. the conversion is deterministic and does not require patient-specific context.

Examples included in v0.1:

• glucose mg/dL <-> mmol/L;
• creatinine mg/dL <-> umol/L;
• Fahrenheit/Kelvin -> Celsius;
• SpO2 fraction -> percent;
• body weight g/lb -> kg;
• height m -> cm.

HbA1c NGSP % and IFCC mmol/mol are intentionally not converted in v0.1 because that relation is not a simple dimensional unit conversion.

D007 canonical units are internal normalization targets. D012 remains responsible for formal terminology/LOINC/OMOP mapping.