LOINC Code 15165-4: Complement C4 (Syn fld) [Mass/Vol]
15165-4 is a LOINC code used to identify Complement C4 (Syn fld) [Mass/Vol] in laboratory and clinical observation data. You may see this code in lab systems, lab reports, EHR exports, interoperability feeds, or other structured clinical data exchanges. LOINC codes identify tests, measurements, observations, survey items, and clinical questions in a standardized way. It is associated with the component Complement C4. It is commonly used with the system or sample type Synv fld.
What is this code?
LOINC codes identify tests, measurements, observations, survey items, and clinical questions in a standardized way. It is associated with the component Complement C4. It is commonly used with the system or sample type Synv fld.
When is it used?
- Used in lab systems, EHRs, and clinical data exchange.
- May identify a test, observation, survey item, or clinical document request rather than a diagnosis.
- Status: ACTIVE
- Order vs observation: Both
What it does not mean
- The code identifies the observation or test, not the actual result.
Key facts
- Complement C4 [Mass/volume] in Synovial fluid
- Complement C4
- Beta 1 E-globulin; Comp; Complmt; HEMATOLOGY/CELL COUNTS; Joint aspirate; Joint fld; Joint flu; Joint fluid; Level; Mass concentration; Point in time; QNT; Quan; Quant; Quantitative; Random; SF; SNV; Syn; Syn fl; Synov; Synovial fluid
Where you may see this code
You may see this code in lab systems, lab reports, EHR exports, interoperability feeds, or other structured clinical data exchanges.
Related SNOMED CT concepts
Related observations and tests
Common synonyms
Frequently asked questions
About this content
This page is prepared by HealthAssure's clinical team using official coding standards from LOINC. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.