| id | No | string | Unique id for inter-element referencing |
| extension | No | Extension[] | Additional content defined by implementations |
| modifierExtension | No | Extension[] | Extensions that cannot be ignored even if unrecognized |
| amount[x] | No | Quantity, Range, string | Used to capture quantitative values for a variety of elements. If only limits are given, the arithmetic mean would be the average. If only a single definite value for a given element is given, it would be captured in this field |
| amountType | No | CodeableConcept | Most elements that require a quantitative value will also have a field called amount type. Amount type should always be specified because the actual value of the amount is often dependent on it. EXAMPLE: In capturing the actual relative amounts of substances or molecular fragments it is essential to indicate whether the amount refers to a mole ratio or weight ratio. For any given element an effort should be made to use same the amount type for all related definitional elements |
| amountText | No | string | A textual comment on a numeric value |
| referenceRange | No | Element | Reference range of possible or expected values |
| - id | No | string | Unique id for inter-element referencing |
| - extension | No | Extension[] | Additional content defined by implementations |
| - lowLimit | No | Quantity | Lower limit possible or expected |
| - highLimit | No | Quantity | Upper limit possible or expected |
