Recovery factor in cleaning validation


Can any one explain how to  calculate recovery factor in cleaning validation ?

All I know is that % of Recovery is calculated by the formula

  (obtained result / expected result) x 100

Is that just similar to % of recovery or some thing different ?


D Mallick



Edited Fri, Oct 18, 2013 2:33 PM

Replies to this Topic


In cleaning validation you will need to demonstrate swab stick recovery and swab recovery.

Known concentration standard solutions are prepared and applied onto individual stainless steel plates separately. Allow the solution to air dry. Swab the complete area with cotton stick and dissolve with diluent and sonicate for 5 minutes. Make up

the solution to known volume with diluent and mix to get the desired concentration.

Inject standard solutions of  known concentration in  duplicate and take  

the mean area and then calculate % recovery of each level as follows,

                      Area of individual swab level    x    std dilution

 % Recovery = ---------------------------------------------------- x 100

                     Area of the corresponding standard solution x sample dilution


I hope this helps.


Dear Manisha,

Yes what you say is right we do the same.



Dear Manisha/Sunil,

Thanks for your reply.But the formula is just simillar to the one I have mentioned earlier.. I saw a calculation formula as

 Test Area x std Dilution x Recovery factor x potency x 1000

----------------------------------------------------------------------- = result in ppm

                           std area x test dilution

In Most of the cases the recovery factor is between 1.1 to 1.2.

My query.. is this recovery factor is just simillar to % of recovery or any thing else ???



From the equation what i can gather is that on a day to day scenario when results need to be declared, a correction is applied for the recovery of the method so that the results reflect the inherent recovery of the method.

Accoding to me this factor will be same as % recovery.  Rgds Manisha


Hi Manisha,

What you have written is correct, I think the value can be calculated from recovery study.

As, if we get % swab recovery between 85, 87, 86, 90, 89 for LOQ, 50%, 100%,150%, 200% during method validation, then the average recovery is 87.4 ie we can say factor is 0.874, so we need to aplpy 0.874 to each result to get actual results during day to day analysis.

i.e. if we get 100µg/100cm2 without applying factor, we get 87.4µg/100cm2 by appling factor. none the less the recovery can be more than 100% also, so in that case we have to apply that factor to get actual results. 

I think I am right, correct me If I am wrong.


Hi Ravindra,

I agree with your interpretation on the same.





Dear All,

Could anybody can explain me, While developing the cleaning method validation Which parameter (LOD / LOQ) is most concern to fixing the specification limit.


If your analytical method shows the accuracy(% Recovery) 85-115% , it is well and good. No need to think about recovery factor.

If not, then you consider the recovery factor in the calculation.

Recovery factor : obtained conc / theoritical conc.


Specification of cleaning method depends on safety factor, maximum dialy dose and Next batch size.

Confusing ............
Is ‘% of recovery' and ‘recovery factor' are same?
Exactly not.
% of recovery is for the calculation of carryover and the formula depends upon the type of sampling i.e. swab / rinse.
Recovery factor is to be established one time to provide the recovered amount of substance from known concentration.
And recovery factor is to be considered in calculating % of recovery.

% Recovery and Recovery factor is same.

100 / % Recovery= Recovery factor.

In rinse or swab calculation, it is in the numerator part of the formula, does not carry any units.

Its a single time event only.

It is a Correction factor for Errror in the cleaning validation study.


Bujji Reddy. Kanchi.


Dear all,

Can you help me for  how  cleaning validation considering visual inspection a should be performed.


Thanking you with regards,



Mr Prahalad Imandar

With regards to Visual Inspection in Cleaning Validation, you are required to have an effective cleaning procedure, documented in form of a SOP. While executing, you need to prepare a protocol stating elaborately all the involved steps cleaning procedure. The invlolved steps can even start right with switching off / cutting off the electrical supply. 

The following steps should be considered inprotocol.

1. Power Disconnection

2. Dismantling the equipment

3. Cleaning as per the validated/standard procedure. (simply as per the SOP)

4. Drying the dismantled parts.

Once the cleaning and subsequent drying process is over, Visual Inspection is to be performed; in prior to any other sampling activity like Rinse or Swab...

The inner and outer surfaces of the equipment are to be verified...

All it depends on how elaborately you develop your cleaning procedure and protocol.... 




Cleaning validation in quality control is mainly for the purpose of recovery study.

Before inplementation of cleaning process in the production(Manufacturing) department, QC needs to establish the recovery factor.


It is better to coduct linearity and use the least recovery factor for MACO Calculation.


The best cleaning validation guide i am posting here.

APIC cleaning validation - new.pdf



Bujji Kanchi.


 Dear all and Mr Bujji Kanchi.

Can any body help me how to calculate viscosity a given liquid using U-tube glass viscometer(Oswald or brooks) PL. TELL ME THE FORMULA TO CALCULATE


Best regards, 


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