Selects ISR samples, performs reanalysis, and documents results.

QA Reviewer: Reviews ISR outcome, flags discrepancies, and ensures compliance with protocol.

Study Director: Authorizes inclusion of ISR data in final bioanalytical reports.

4. Accountability

The Head of the Bioanalytical Department is accountable for ensuring ISR compliance, accuracy of data comparison, and documentation integrity.

5. Procedure

5.1 ISR Sample Selection

1. Select ≥10% of total study subjects for ISR.
2. From each selected subject, choose 2 samples at different time points (preferably around C_max and elimination phase).
3. ISR samples should be evenly distributed across analytical runs and treatment arms.

5.2 Sample Retrieval and Preparation

1. Retrieve original sample vials from storage (−20°C or −70°C).
2. Thaw under controlled conditions, mix gently, and prepare for extraction per original method.
3. Document sample handling in Annexure-1: ISR Sample Tracking Log.

5.3 Reanalysis Process

1. Run ISR samples alongside freshly prepared calibration and QC samples.
2. Use the same validated method and instrument settings as in the original run.
3. Ensure ISR injections are randomized within the analytical sequence.

5.4 Evaluation Criteria

1. Calculate % difference between original and ISR result for each sample:
   % Difference = [(Reanalysis − Original) / Mean] × 100
2. Acceptance Criteria:
   • ≥67% of ISR results must be within ±20% of original value.
3. Document comparative data in Annexure-2: ISR Evaluation Summary Sheet.

5.5 Investigation of ISR Failure

1. If ISR criteria are not met:
   • Initiate deviation report and root cause investigation.
   • Assess analytical method performance, extraction recovery, or analyst variability.
   • Repeat ISR if justified, with justification documented in Annexure-3: ISR Deviation Report.

5.6 Reporting

1. Include ISR tables, chromatograms, and results in the final bioanalytical study report.
2. State compliance with ISR criteria and interpretation of outcome.

6. Abbreviations

• BA/BE: Bioavailability/Bioequivalence
• ISR: Incurred Sample Reanalysis
• C_max: Maximum Observed Concentration
• QA: Quality Assurance
• PK: Pharmacokinetics

7. Documents

1. ISR Sample Tracking Log – Annexure-1
2. ISR Evaluation Summary Sheet – Annexure-2
3. ISR Deviation Report – Annexure-3

8. References

• ICH M10: Bioanalytical Method Validation Guideline
• US FDA Guidance for Industry: Bioanalytical Method Validation
• EMA Guidelines on Bioanalytical Method Validation

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: ISR Sample Tracking Log

Subject ID	Time Point	Sample ID	Storage Location	Thaw Date	Analyst
101	2hr	BE101-TP2	−70°C Freezer A	15/04/2025	Rajesh Kumar

Annexure-2: ISR Evaluation Summary Sheet

Sample ID	Original (ng/mL)	Reanalysis (ng/mL)	% Difference	Acceptable
BE101-TP2	18.3	19.1	4.3%	Yes

Annexure-3: ISR Deviation Report

Date	Sample ID	Deviation Description	Root Cause	CAPA Initiated
16/04/2025	BE101-TP6	ISR value deviated by 35%	Low recovery due to degradation	Repeat ISR + stability review

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	Updated with ICH M10 alignment and deviation management	Regulatory update	QA Head