In pharmaceuticals alert and action limits are very important. These limits are used to have effective control over the process.
Alert Limits: Alert limits are in house limits which are defined based on the trend analysis. These limits are like a barrier before the final action limits, given by different regulatory agencies. We have to be alert if microbial count reach to this alert level. It is not necessary to take any action when count reach to alert limit level but we have to be alert as this is a trigger that something is going wrong within the environment and microbial contamination is increasing in the area.
Action Limits: Action limits are also in house limits which are defined based on the trend analysis. When microbial contamination reach to these action limits then action is mandatory to control the contamination in area otherwise if not controlled, we might get area failure. These alert and action limits must be less then the final limits defined by different guidelines and regulatory agencies. For example in case of settle plate exposure, 5 cfu's is the final limit for class B area defined by EU GMP and Drug and Cosmetic act (Schedule M). If we work on this final limit of 5 cfu's then there are chances that we may get more than 5 cfu's in class B and this results in area failure because there is no limit barrier before this final limit. But if we define in house limits like 3 cfu's for alert limit and 4 cfu's for action limits (based on trend data) then we have two barriers before the final limit and there would not be any chance of area failure because if microbial count increases and reach at this in house alert and action limit then we have lot of time to control the area by taking effective action. But if we work with final limits mentioned in guidelines then area results would be either less then 5 cfu's or more than 5 cfu's which means results would be either pass or fail. So, its better to set alert and action limits based on the trend data.
Sir, how to calculate alert and action limits on the basis of trends?
ReplyDeleteDear Amrish, there are different formula available for calculation of alert and action limits. But I would like to tell you a simple formula which is following in many pharmaceutical companies for calculation of alert and action limit of water and environment monitoring trends.
ReplyDeleteFor alert limit: (Avg. +2)* SD
For action limit: (Avg. +3)* SD
Here Avg. is average of microbial count on basis of trend data
SD is standard deviation
What is your reference?
ReplyDeletei want to set up an alert and action limits for Non sterile facility what should be the way forward and any specific guidelines for the same???
ReplyDeleteDear sandeep/Amrish
ReplyDeletei just whant to correct this formula
For alert limit: (Avg. +2)* SD
For action limit: (Avg. +6)* SD
thanks
chandan
action limit: (Avg. +3)* SD
DeleteCorrection please:
DeleteAlert Limit = Avg+(2*SD)
Action Limit = Avg+(3*SD)
Could you tell us the reference, please?
DeleteWho guidline is who trf 970 2012 is correct
DeleteWho guidline is who trf 970 2012 is correct
DeleteSir, What to do when the alert limit is that same as the action limit. The trend results are very low.
ReplyDeleteDear Sir,
ReplyDeleteas you told avove information, It is not necessary to take any action when count reach to alert limit level but we have to be alert as this is a trigger that something is going wrong within the environment and microbial contamination is increasing in the area.
So could you explain more detail for above information
due to the alert limit alway happen in our company. we will do investigation.
Good day
ReplyDeleteSo can in-house alert limits be changed? If my limits were set 16years ago for example can I re-set the limits now because maybe my trends have changed over the years die to better equipment etc?
Yes, you can change your alert and action limits based on the trend data. You can make more stringent alert and action limits.
DeleteDear sir
ReplyDeleteIn case of SD, which value take SD
Dear Sanjay, Standard deviation shall be taken for observed count.
DeleteThis comment has been removed by the author.
ReplyDeleteIn case of PSC and WFI microbial count is very less(avg.<01) then how to set alert and action limit and what it would be.
ReplyDeleteIn case of PSC and WFI microbial count is very less(avg.<01) then how to set alert and action limit and what it would be.
ReplyDeleteIn case of PSC and WFI microbial count is very less(avg.<01) then how to set alert and action limit and what it would be.
ReplyDelete