> ## Documentation Index
> Fetch the complete documentation index at: https://docs.medera.info/llms.txt
> Use this file to discover all available pages before exploring further.

# LOINC

> Lab observations + validated BH instrument codes.

LOINC (Logical Observation Identifiers Names and Codes) is the international standard for identifying lab tests, clinical observations, and documents. Medera codes both **lab orders / results** and **validated BH instruments** to LOINC for FHIR Observation interoperability.

## Lab orders / results

Standard LOINC applies — lipid panel, CBC, basic metabolic, TSH, drug screen, etc. The Medical Coding Agent surfaces the most-likely LOINC for any laboratory mention in the note.

## BH instrument LOINC codes

Validated BH instruments emit as LOINC-coded `Observation` resources so they round-trip cleanly through FHIR.

| Instrument                   | LOINC     | Notes                        |
| :--------------------------- | :-------- | :--------------------------- |
| PHQ-9 total score            | `44261-6` | Depression severity score    |
| PHQ-9 item 9 (suicide)       | `44262-4` | Item-level flag              |
| GAD-7 total score            | `70274-6` | Generalized anxiety severity |
| AUDIT-C total score          | `75624-7` | Alcohol use screen           |
| AUDIT total score            | `75626-2` | Full AUDIT                   |
| C-SSRS — past month severity | `93374-8` | Suicide-ideation severity    |
| C-SSRS — past month behavior | `93375-5` | Suicide-behavior severity    |
| MDQ total score              | `71354-5` | Mood Disorder Questionnaire  |
| ASRS total score             | `93446-4` | Adult ADHD self-report       |
| PCL-5 total score            | `89204-2` | PTSD Checklist DSM-5         |
| Edinburgh PND total          | `71354-x` | Postnatal depression         |

## Emission

When `/sessions` or `/transcripts` runs an instrument inline, each completed instrument emits as a FHIR `Observation`:

```json theme={"system"}
{
  "resourceType": "Observation",
  "status": "final",
  "code": { "coding": [{ "system": "http://loinc.org", "code": "44261-6", "display": "Patient Health Questionnaire 9 item (PHQ-9) total score" }] },
  "valueQuantity": { "value": 14, "unit": "score" },
  "interpretation": [{ "coding": [{ "code": "MOD", "display": "Moderate" }] }],
  "derivedFrom": [{ "reference": "DocumentReference/doc_abc#span_412_489" }]
}
```

***

## What's next

<CardGroup cols={2}>
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  <Card title="Coding systems" icon="https://mintcdn.com/medera-357fd587/iC-6rAuwl-0aQSw_/icons/ui/layers.svg?fit=max&auto=format&n=iC-6rAuwl-0aQSw_&q=85&s=b19e6f39887a8a61762fcb53957d2271" href="/coding/coding-systems" width="40" height="40" data-path="icons/ui/layers.svg">Feature matrix + pairings.</Card>
  <Card title="Encounter coding" icon="https://mintcdn.com/medera-357fd587/iC-6rAuwl-0aQSw_/icons/ui/clipboard-check.svg?fit=max&auto=format&n=iC-6rAuwl-0aQSw_&q=85&s=9cf869d685b45a2ec31be2b3d675a841" href="/coding/encounter-coding" width="40" height="40" data-path="icons/ui/clipboard-check.svg">Use cases.</Card>
  <Card title="Validated screeners" icon="https://mintcdn.com/medera-357fd587/iC-6rAuwl-0aQSw_/icons/ui/clipboard.svg?fit=max&auto=format&n=iC-6rAuwl-0aQSw_&q=85&s=1720b08721e4d7118ecee190cae42ff9" href="/agentic/experts/validated-screener" width="40" height="40" data-path="icons/ui/clipboard.svg">Screener Expert.</Card>
</CardGroup>