C3174221
Which best describes how you are usually affected by severe headaches:Find:Pt:^Patient:Ord:PhenX
Concept
CUIC3174221
PreferredWhich best describes how you are usually affected by severe headaches:Find:Pt:^Patient:Ord:PhenX
Cross-maps
LOINC65378-2
Source vocabularies
Atoms not loaded for this concept.
# same page, as API
GET autoicdapi.com/api/v1/reference/umls/C3174221
GET autoicdapi.com/api/v1/translate?code=C3174221&from=umls&to=snomed-ct
Common questions
What is the UMLS CUI for Which best describes how you are usually affected by severe headaches:Find:Pt:^Patient:Ord:PhenX?
Which best describes how you are usually affected by severe headaches:Find:Pt:^Patient:Ord:PhenX is coded as C3174221 in UMLS.
What is UMLS code C3174221?
C3174221 is the UMLS identifier for Which best describes how you are usually affected by severe headaches:Find:Pt:^Patient:Ord:PhenX. It is included in the current NLM UMLS Metathesaurus release.
What is the LOINC mapping for C3174221?
C3174221 maps to LOINC 65378-2.
UMLS, plainly answered
What is UMLS?
The Unified Medical Language System is the NLM's meta-terminology that unifies SNOMED CT, ICD-10, ICD-11, RxNorm, LOINC, MeSH, and around 200 other source vocabularies under a single concept identifier (CUI). One UMLS CUI can group dozens of synonymous codes from different terminologies.
What is a CUI and why does it matter?
A CUI is a stable identifier (like C0011860) that points at a single clinical idea regardless of how that idea is encoded in any specific vocabulary. CUIs are the most reliable way to bridge between terminologies when you need to compare or merge data from multiple sources.
How does UMLS help with cross-mapping?
Every UMLS concept page lists the codes it groups together. That gives you a free crosswalk: a SNOMED concept and an ICD-10 code that share a CUI describe the same clinical idea. Our cross_references API returns these groupings inline.
Is the API free to use?
Browsing the directory is free. Programmatic /api/v1/reference/umls/* access needs an API key. Production volume requires a paid tier.
How fresh is the UMLS data?
We track NLM's twice-yearly releases (May AB and November AB). Each release brings new concepts, retirements, and atom updates from the source vocabularies, and our index reflects them within the same week.
Do I need a UMLS license?
Yes. The UMLS Metathesaurus License Agreement is free but requires an NLM UTS account. Customers in production need their own license. Free-tier evaluation use is permitted under the standard terms.