← Product Code [MOJ](/submissions/TX/subpart-d%E2%80%94clinical-toxicology-test-systems/MOJ) · K230161

# ONLINE TDM Phenytoin - Free Phenytoin application (K230161)

_Roche Diagnostics · MOJ · Mar 30, 2023 · Clinical Toxicology · SESE_

**Canonical URL:** https://fda.innolitics.com/submissions/CH/subpart-d%E2%80%94clinical-toxicology-test-systems/MOJ/K230161

## Device Facts

- **Applicant:** Roche Diagnostics
- **Product Code:** [MOJ](/submissions/TX/subpart-d%E2%80%94clinical-toxicology-test-systems/MOJ.md)
- **Decision Date:** Mar 30, 2023
- **Decision:** SESE
- **Submission Type:** Traditional
- **Regulation:** 21 CFR 862.3350
- **Device Class:** Class 2
- **Review Panel:** Clinical Toxicology

## Indications for Use

ONLINE TDM Phenytoin - Free Phenytoin application is an in vitro test for the quantitative determination of free phenytoin in human serum and plasma on cobas c systems. The determination of free phenytoin is used in monitoring levels of free phenytoin to ensure appropriate therapy.

## Device Story

Device is an in vitro diagnostic test for quantitative determination of free phenytoin in human serum and plasma. Sample processing requires ultrafiltration to remove bound phenytoin prior to measurement. Principle of operation is Kinetic Interaction of Microparticles in a Solution (KIMS); phenytoin antibody is covalently coupled to microparticles; drug derivative linked to macromolecule. Competitive reaction occurs between drug conjugate and phenytoin in sample for binding to antibody on microparticles; resulting turbidity is photometrically detected and inversely proportional to drug concentration. Used in clinical laboratories on cobas c systems. Healthcare providers use output to monitor free phenytoin levels for therapeutic management. Benefits include accurate quantification of free drug fraction to guide clinical dosing decisions.

## Clinical Evidence

Bench testing only. Performance evaluated on cobas c 503 analyzer. Precision (repeatability/intermediate) met acceptance criteria (CVs 2.1-3.5%). Linearity confirmed for 0.400-4.00 µg/mL. Method comparison against COBAS INTEGRA 400 plus (n=138) showed strong correlation (Passing/Bablok slope 1.035, r=0.998). Interference studies evaluated endogenous substances and exogenous drugs; cross-reactivity and matrix effects (serum, Li-Heparin, K2-EDTA, K3-EDTA) met acceptance criteria.

## Technological Characteristics

In vitro diagnostic assay using KIMS (Kinetic Interaction of Microparticles in a Solution). Reagents: R1 (phenytoin conjugate, PIPES buffer) and R2 (anti-phenytoin antibody, latex microparticles). Measuring range: 0.400-4.00 µg/mL. Instrumentation: cobas c systems (e.g., cobas c 503). Sample type: serum and plasma (Li-Heparin, K2-EDTA, K3-EDTA). Requires pre-analytical ultrafiltration.

## Regulatory Identification

A diphenylhydantoin test system is a device intended to measure diphenylhydantoin, an antiepileptic drug, in human specimens. Measurements obtained by this device are used in the diagnosis and treatment of diphenylhydantoin overdose and in monitoring levels of diphenylhydantoin to ensure appropriate therapy.

## Submission Summary (Full Text)

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# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION
## TRIAGE-QUICK REVIEW DECISION SUMMARY

Statement for the Record, K230161

This 510(k) was reviewed under the Triage Program. This program represents an internal workload management tool intended to reduce internal FDA review resources for 510(k) applications that are of good quality upon receipt by FDA.

The information in the 510(k) is complete and supports a substantial equivalence (SE) determination. Please refer to the applicant’s 510(k) summary for a summary of the information that supports this SE determination.

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**Source:** [https://fda.innolitics.com/submissions/CH/subpart-d%E2%80%94clinical-toxicology-test-systems/MOJ/K230161](https://fda.innolitics.com/submissions/CH/subpart-d%E2%80%94clinical-toxicology-test-systems/MOJ/K230161)

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