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

# Screening

> Every prescription is checked against the patient's allergies, medications and diagnoses.

Photon screens a prescription each time its drug resolves or it changes. It checks the drug against the patient's record and returns each conflict it finds in the prescription's `screeningAlerts`.

An [order](/docs/network/order#screening) also screens its prescriptions together. Interactions between them come back in the order's `screeningAlerts`, not on each prescription.

Screening can only check what's on file. [Sync the patient's](/docs/integrations/sync-patients) allergies, medications and diagnoses before drafting. A patient with an empty record gets no alerts, but that doesn't mean the drug is safe.

## Alerts

| Field | Description |
| - | - |
| `type` | What it conflicts with: `DRUG` (another medication), `ALLERGEN` (an allergy) or `CONDITION` (a diagnosis) |
| `severity` | `MINOR`, `MODERATE` or `MAJOR` |
| `description` | A plain-language explanation, ready to show the prescriber |
| `involvedEntities` | The drug and the allergen, medication or condition involved |
| `category` | Usually `SAFETY` |
| `options` | An alternative drug that avoids the conflict, when there is one |

```json theme={"dark"}
{
  "severity": "MODERATE",
  "type": "ALLERGEN",
  "category": "SAFETY",
  "description": "Amoxicillin is a penicillin-class antibiotic. The patient has a recorded allergy to amoxicillin.",
  "involvedEntities": [
    { "id": "med_…", "name": "Amoxicillin 500 MG Oral Capsule" },
    { "id": "alg_…", "name": "Amoxicillin" }
  ]
}
```

## Showing alerts

Alerts are advisory: none of them stops a prescriber from signing or sending. Show every alert to the prescriber before they sign, and the order's alerts before they send. Prescribe shows each prescription's alerts on its card, above the sig, until it's signed. Explicit acknowledgement of individual alerts when signing is planned.

<Warning>
  Screening relies on coded entries. An allergy recorded without an RxNorm code, such as a drug-class allergy entered by name, may not be screened. Send allergies by `rxNormId` whenever you can.
</Warning>


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