Analyst: Identifies reinjection need, documents justification, and reinjects samples as per procedure.

Instrument Operator: Verifies system readiness and ensures same instrument configuration is maintained during reinjection.

Supervisor: Approves reinjection requests and reviews final results.

QA Officer: Reviews reinjection logs and approves inclusion in final report.

4. Accountability

The Head of Bioanalytical Operations is accountable for ensuring that reinjections are scientifically justified, properly documented, and aligned with regulatory expectations for data traceability.

5. Procedure

5.1 Identification of Reinjection Need

1. Review sample chromatograms for abnormal peak shape, system interruption, missed injections, or inconsistent response.
2. Reinjection may be considered if:
   • The sample was not acquired due to instrument failure
   • The peak was not integrated properly due to detector noise or pressure fluctuation
   • System suitability failed mid-run
   • The injection was skipped
3. Fill and submit the Reinjection Request Form (Annexure-1).

5.2 Reinjection Conditions

1. Reinjection must be performed using:
   • The same processed vial (no reprocessing allowed)
   • Same instrument and column as initial injection
   • Same sequence conditions (mobile phase, gradient, injection volume)
2. Reinjection must occur within the validated autosampler stability window (e.g., 48 hours at 4°C).

5.3 Documentation Requirements

1. Record the sample ID, reinjection reason, original injection date/time, reinjection date/time, and chromatographic observations in Annexure-2: Reinjection Log Sheet.
2. Annotate reinjection chromatograms with justification reference to Annexure-1.
3. Maintain the audit trail from LIMS or instrument software showing both injection events.

5.4 Acceptance Criteria

1. Reinjected results must comply with accepted QC and calibration standards for the run.
2. If reinjected concentration deviates by >20% from original and justification is invalid, both results must be rejected and sample reprocessing initiated (with QA approval).
3. Final result must be traceable with clear justification.

5.5 QA Review and Finalization

1. QA reviews the reinjection request form, chromatograms, system suitability, and audit trail.
2. Once approved, the reinjected value may be considered valid for study report inclusion.
3. All reinjections should be summarized in the bioanalytical method validation or study sample analysis report.

6. Abbreviations

• BA/BE: Bioavailability/Bioequivalence
• QA: Quality Assurance
• LC-MS/MS: Liquid Chromatography–Mass Spectrometry
• LIMS: Laboratory Information Management System

7. Documents

1. Reinjection Request Form – Annexure-1
2. Reinjection Log Sheet – Annexure-2

8. References

• ICH M10: Bioanalytical Method Validation
• US FDA Guidance for Industry: Bioanalytical Method Validation (2022)
• Internal Bioanalytical Audit SOPs

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Reinjection Request Form

Sample ID	BAE-182-04
Original Injection Date/Time	16/04/2025, 11:10 AM
Reinjection Date/Time	17/04/2025, 10:50 AM
Reason for Reinjection	Chromatogram failure due to pressure spike
Requested By	Sunita Reddy
Approved By	Dr. Anil Mehta

Annexure-2: Reinjection Log Sheet

Sample ID	Injection Type	Date/Time	Result (ng/mL)	Status
BAE-182-04	Original	16/04/2025	N/A	Rejected
BAE-182-04	Reinjection	17/04/2025	183.2	Accepted

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
01/01/2022	1.0	Initial issue	New SOP	QA Head
17/04/2025	2.0	Expanded reinjection justification process and annexures	Audit Compliance	QA Head