Repeat Analysis of Samples

 1.0 Objective

To describe the procedure for identification of samples for repeat analysis and their acceptance criteria.

2.0 Scope

This procedure applicable to all bioassays for the estimation of unknown concentrations (Routine Drug Analysis) at Biopharmaceutical Research Laboratory.

3.0 Responsibility

Study Director/ Principal Investigator/ Chromatographic Reviewer.

4.0 References

4.1 Guidance for Industry: Bioanalytical Method Validation, US-FDA, May 2001.

4.2 Analytical method validation, ICH Step 4.

4.3 Manual for good bioavailability and bioequivalence practices, Vol 1, Module 2: Analytical Step (Anvisa).

4.4 BA-107 : Project Management

4.5 BA-110 : Bioanalytical Method Validation.

4.6 BA-111 : Routine Drug Analysis.

4.7 BA-112 : Chromatographic Review and Acceptance Criteria.

5.0 Abbreviations

5.1 LLOQ : Lower Limit Of Quantification

5.2 ULOQ : Upper Limit Of Quantification

5.3 CCS : Calibration Curve Standard

6.0 Chemicals

6.1 None

7.0 Procedure

7.1 Study Director/ Principal Investigator 

7.1.1 Designate the Chromatographic Reviewer for method validation, sample analysis and complete the form ‘Project Delegation.

7.1.2 Review and approve ‘Samples for Repeat Analysis’.

7.2 Chromatographic Reviewer

7.2.1 The designated chromatographic reviewer shall review and identify samples for repeat analysis.

7.2.2 Any data or value in question shall be identified for repeat analysis.  Each such chromatogram shall be identified by stamping ‘Repeat analysis-CODE_____’ in red colour.  

7.2.3 Reanalyze the sample after the approval using repeat analysis form

7.2.4 After considering the acceptance criteria, chromatogram of rejected data shall be stamped as ‘Chromatogram Not Used’ in black colour.

7.2 Repeat analysis categories

7.2.1 Code a: Rejected Analytical Batch

Reject samples of a batch that does not meet the acceptance criteria as explained in SOP,    ‘Routine Drug analysis : BA-111’. The samples of the batch shall be coded ‘a’. Reanalyze the samples with fresh CCs.  Reject the data calculated from the previous curve and do not report the same.  Repeat once and use the repeat concentration for calculation.

7.2.2 Code b: Error during analysis.

Any sample lost due to equipment failure, technical error, broken vials, data file lost, etc during the analysis shall be coded ‘b’. Repeat once and use the repeat concentration for calculation.

7.2.3 Code c: Bad Chromatography

Any sample exhibiting bad chromatography as explained in SOP ‘Chromatographic Review and Acceptance Criteria : BA-112 shall be coded ‘c’. Repeat once and use the repeat concentration for calculation.

7.2.4 Code d: Pre dose Sample

The responses of interfering peaks at the retention time of the analyte is more than that of the response of LLOQ the analysis shall be coded ‘d’. Repeat once and use the concentration. 

7.2.5 Code e: Above the limit of Calibration curve

When the calculated concentration of the study sample exceeds the concentration of the ULOQ the sample shall be coded as ‘e’. Dilute the sample with similar blank matrix to bring the concentration within the ULOQ as per validation report and repeat the sample once, apply the appropriate dilution factor to calculate the concentration and use the repeated concentration for analysis.

7.2.6 Code f: Internal standard variation

Samples found to show internal standard variation shall be coded as ‘f’. 20-200% variation of area is acceptable. Repeat the sample once, if not complying with acceptance criteria and use repeated concentration for calculations.

7.2.7 Code g: Error in sample processing

Samples found to be processed improperly (eg. Errors in dilution, extraction etc) shall be coded as ’g’. This also includes the samples whose vials / sample tubes are interchanged during storage box or auto injector or during sample handling. Repeat once and use the repeated concentration for calculations.

7.2.8 Pharmcokinetic outliers:

7.2.8.1 The pharmacokinetic outlier will be identified by sponsor.

7.2.8.2 The analysis will be carried out upon sponsor written or e-mail request.

7.2.8.3 Pharmacokinetic outlier detection: Outliers for Peak concentration (Cmax) will be defined as follows:

7.2.8.3.1  Outlier 1 < Q1 - (Q3 - Q1) x 1.5 or Q3 + (Q3 - Q1) x 1.5 < Outlier 1

7.2.8.3.2  Outlier 2 < Q1 - (Q3 - Q1) x 3.0 or Q3 + (Q3 - Q1) x 3.0 < Outlier 2.

7.2.8.3.3  Q = quartile; Q1 = quartile 1; Q2 = quartile 2; Q3 = quartile 3.

7.2.8.4 The decision of accepting appropriate value or rejecting both the values should be to facilitate the best fir Pharmacokinetic modeling.

Type Data Handling

A Less than 20 % difference from original value, Report Original Value

B Between 20 to 30 % difference from original value, Report Average Value

C More than 30 % difference from original value, Report Appropriate or Reject both values 

7.3 The procedure for correcting the errors

7.3.1 Reassays or repeat analysis should be done if the sample volume allows.

7.3.2 According to the Code-e when the concentrations are high, dilution integrity has to be validated and then dilute the sample with matrix and then analyze. 

7.3.3 The errors mentioned in the Code a, Code b and Code c shall be repeated once if the sample volume allows or else result shall be omitted from final reporting values.

7.3.4 For methods involving multiple analytes, each analyte should be treated independently for acceptance criteria.

8.0 Records

8.1 FF-114-15 : Repeat Analysis