SOP for Reporting of analytical values and rounding off the digits | USP Chapter for Rounding off | USP guidance on significant figures and rounding |
1.0 OBJECTIVE :
- To lay down the procedure for establishing guidelines for reporting of analytical values and rounding off the digits.
2.0 SCOPE :
- This SOP is applicable for reporting of analytical values and rounding off the digits.
3.0 RESPONSIBILITY :
- The QC Staff shall be responsible for:
- Following the procedure mentioned in SOP.
- The Manager-QC shall be responsible for:
- Ensuring compliance of the SOP.
- The Manager-QA shall be responsible for:
- Ensuring compliance of the SOP.
4.0 ACCOUNTABILITY:
- Manager-QC
5.0 PROCEDURE :
5.1 After completion of the analysis, the analytical chemist shall calculate the analytical result in the test data sheet and compare with the stated limits in the specification.
5.2 The calculated analytical values shall be reported in the test data sheet, COAs and raw data sheets as given in the following table:
5.3 When reporting the results of the related substances, see the disregarding limits of unknown impurities and LOD & LOQ limits of known impurities. Do not consider the unknown impurities which are below the disregarding limit.
5.4 If the Known impurity is less than the LOD, do not consider for calculation.
5.5 If the Impurity value is more than LOD limit and less than the LOQ, do not consider for calculating total impurities and individual impurities.
5.6 Any known impurity value more than the LOQ limit shall be considered for calculation of total impurities.
5.7 If the calculated value(s) contains more digits in the decimal place than that in the stated limit, the digits after decimal place shall be rounded off as described below;
- Rounding off shall be done by considering only one digit in the decimal place to the right of the last place in the limit expression as shown in the illustration below.
- If the digit is smaller than 5, it shall be eliminated and the preceding digit shall remain unchanged.
- If the digit is greater than or equal to 5, it shall be eliminated and the preceding digit shall be increased by one.
Limits are fixed numbers and shall not be rounded off.
5.8 When the analytical method or test requires quantifications, in such cases, the analytical result shall be expressed as observed numerical value.
5.9 When the analytical method or test does not require quantification, in such cases the analytical result shall be expressed as “Conform” or “does not conform” as the case may be on Certificate of Analysis. However, in the test data sheet, the actual observation of analysis shall be specified (for example: Less than 50 ppm, colour intensity of sample solution is not more than that of standard solution “x” or formation of specific colour to the solution or formation of precipitate).
6.0 ABBREVIATIONS:
| Abbreviation | Expanded form |
| QA | Quality Assurance |
| QC | Quality Control |
| SOP | Standard operating Procedure |
| NMT | Not more than |
| LOD | Limit of detection |
| LOQ | Limit of quantitation |
| COA | Certificate of analysis |
| LOD | Loss on drying |
7.0 ANNEXURES:
NIL
8.0 SOP REFERENCES
- General notices (7.20.Rounding Rules) USP 40 NF 35
END OF THE SOP