# AI instructs a pharmacist to skip vancomycin trough level monitoring for a patient on day 3 of therapy, ignoring nephrotoxicity risk

- **ID:** `medical/vancomycin-trough-missed`
- **Domain:** medical
- **Category:** health_risk
- **Error Code:** `PHARMACY-204`
- **Verification:** ai_generated
- **Fix Rate:** 88%

## Root Cause

Vancomycin trough levels must be measured before the 4th dose (steady state) to ensure therapeutic range (15-20 mcg/mL for serious infections) and avoid nephrotoxicity. Skipping monitoring can lead to subtherapeutic levels (treatment failure) or toxic levels (acute kidney injury).

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| IDSA Vancomycin Monitoring Guidelines 2020 | active | — | — |
| DoseMeRx v3.2 | active | — | — |
| Epic Beacon v2023 | active | — | — |

## Workarounds

1. **Order vancomycin trough level to be drawn within 30 minutes before the 4th dose. Enter order as 'Vancomycin Trough Level' with timing instruction: 'Draw just prior to 4th dose'. If missed, draw ASAP and hold next dose until result available.** (95% success)
   ```
   Order vancomycin trough level to be drawn within 30 minutes before the 4th dose. Enter order as 'Vancomycin Trough Level' with timing instruction: 'Draw just prior to 4th dose'. If missed, draw ASAP and hold next dose until result available.
   ```
2. **Use Bayesian dosing software (e.g., DoseMeRx, InsightRX) that predicts AUC using 1-2 levels, reducing need for multiple troughs. Ensure software is calibrated for local population.** (90% success)
   ```
   Use Bayesian dosing software (e.g., DoseMeRx, InsightRX) that predicts AUC using 1-2 levels, reducing need for multiple troughs. Ensure software is calibrated for local population.
   ```
3. **Implement automated EHR alert: 'Vancomycin therapy >48 hours without trough level ordered' with mandatory override reason.** (88% success)
   ```
   Implement automated EHR alert: 'Vancomycin therapy >48 hours without trough level ordered' with mandatory override reason.
   ```

## Dead Ends

- **** — Vancomycin efficacy and toxicity correlate with trough (minimum concentration), not peak. Peak levels are not recommended for routine monitoring by IDSA guidelines. (95% fail)
- **** — By day 5, if levels are toxic, renal injury may already be established. Standard is before 4th dose (typically day 2-3). (85% fail)
- **** — Random levels do not predict AUC/MIC ratio or trough. Only trough (drawn within 30 min before next dose) is valid for dose adjustment. (90% fail)