Monday 16 February 2015

What are alert and action limits and why they are so important in pharmaceuticals?

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.

20 comments:

  1. Sir, how to calculate alert and action limits on the basis of trends?

    ReplyDelete
  2. Dear 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.
    For 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

    ReplyDelete
  3. What is your reference?

    ReplyDelete
  4. i 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???

    ReplyDelete
  5. Dear sandeep/Amrish
    i just whant to correct this formula
    For alert limit: (Avg. +2)* SD
    For action limit: (Avg. +6)* SD
    thanks
    chandan

    ReplyDelete
    Replies
    1. Correction please:

      Alert Limit = Avg+(2*SD)
      Action Limit = Avg+(3*SD)

      Delete
    2. Could you tell us the reference, please?

      Delete
    3. Who guidline is who trf 970 2012 is correct

      Delete
    4. Who guidline is who trf 970 2012 is correct

      Delete
  6. Sir, What to do when the alert limit is that same as the action limit. The trend results are very low.

    ReplyDelete
  7. Dear Sir,
    as 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.

    ReplyDelete
  8. Good day
    So 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?

    ReplyDelete
    Replies
    1. Yes, you can change your alert and action limits based on the trend data. You can make more stringent alert and action limits.

      Delete
  9. Dear sir
    In case of SD, which value take SD

    ReplyDelete
    Replies
    1. Dear Sanjay, Standard deviation shall be taken for observed count.

      Delete
  10. This comment has been removed by the author.

    ReplyDelete
  11. In 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
  12. In 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
  13. In 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