By PulsHealth. Updated
Research reviewed .
What does the Apple Health blood-type field contain?
Blood Type stores the ABO/Rh label entered in a Health profile. An authorized app reads the current value through HKHealthStore.bloodType(). Third-party apps cannot write the characteristic, and the value is not a timestamped blood-test result.
How are the labels encoded?
| Raw value | HealthKit label | Blood group |
|---|---|---|
| 0 | notSet | Unset or unavailable because read access was denied |
| 1 | aPositive | A+ |
| 2 | aNegative | A− |
| 3 | bPositive | B+ |
| 4 | bNegative | B− |
| 5 | abPositive | AB+ |
| 6 | abNegative | AB− |
| 7 | oPositive | O+ |
| 8 | oNegative | O− |
These integers are identifiers, not a scale. For example, O− is not a higher value than A+. notSet supplies no blood-group information and cannot distinguish missing entry from denied permission.
Is this enough to verify blood compatibility?
No. A Health profile entry is not a laboratory blood-typing or compatibility result. ABO/Rh patient testing and crossmatching are separate clinical procedures, as reflected in the Red Cross laboratory testing catalog. Keep the profile label separate from those verified results; it cannot substitute for testing before a transfusion.
The field represents the common ABO/Rh labels only. It is not a complete record of other blood-group systems, antibodies or compatibility testing. Do not infer a diagnosis, a treatment plan or individual disease risk from the label alone.
Does HealthKit provide a history of changes?
This getter supplies the current characteristic. It does not expose a sequence of dated samples, so there is no recording cadence or trend graph to reconstruct from it. A changed selection could be a correction; the field alone does not explain why it changed.
PulsHealth's current sample sync catalog and profile schema do not store this characteristic. That storage limitation does not establish whether the user has entered a blood type on their phone.
Where does this fit in a health profile?
Date of Birth and Biological Sex are other profile characteristics. They share the distinction between current profile information and time-stamped measurements, but answer different questions and should not be inferred from one another.
Understanding your records
Recording frequency, source and coverage affect what you can conclude from this data. Read the recording guide.