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deepakpangavhane
Junior

India,
2018-09-03 08:28

Posting: # 19205
Views: 755
 

 recoveries more than 100% [Bioanalytics]

Hi everyone!

The % recovery was 107.80%, 112.65% and 105.92% for the low quality control (LQC) and middle quality controls (MQC2 and MQC1), respectively. Whereas % recovery for higher quality control (HQC) was 98.25%.

The % recovery was determined by comparing the mean peak area of 6 replicates of extracted quality control samples at High, Middle and Low concentrations against respective mean peak area of 6 replicates of un-extracted quality control samples at High, Middle and Low concentrations. Internal standard used was deuterated.

Kindly confirm recoveries markedly higher than 100% for LQC, MQC2 and MQC1 are acceptable as per USFDA guidelines?? Also specify reason for higher recoveries.
Ohlbe
Hero

France,
2018-09-03 19:21

@ deepakpangavhane
Posting: # 19231
Views: 663
 

 recoveries more than 100%

Dear Deepak,

» The % recovery was determined by comparing the mean peak area of 6 replicates of extracted quality control samples at High, Middle and Low concentrations against respective mean peak area of 6 replicates of un-extracted quality control samples at High, Middle and Low concentrations.

Meaning that what you observe is a mix of extraction recovery and matrix effect. If you want to see the true extraction recovery you have to compare to samples spiked post-extraction. You can combine with matrix effects experiments.

» Internal standard used was deuterated.

Makes no difference. You are looking at peak areas, not peak area ratios.

» Kindly confirm recoveries markedly higher than 100% for LQC, MQC2 and MQC1 are acceptable as per USFDA guidelines??

Did you see any limit for absolute recovery in either direction in the FDA guidance ?

» Also specify reason for higher recoveries.

Multiple. The most probable: analytical variability (your results are well within the 15 % acceptance limits for precision and accuracy). Other possibilities include ion enhancement, sample preparation, calculation errors...

Regards
Ohlbe
Ladi
Junior

Thailand,
2018-09-04 03:51

@ deepakpangavhane
Posting: # 19232
Views: 649
 

 recoveries more than 100%

Hello Deepak and Ohlbe,

» The % recovery was 107.80%, 112.65% and 105.92% for the low quality control (LQC) and middle quality controls (MQC2 and MQC1), respectively. Whereas % recovery for higher quality control (HQC) was 98.25%.

My lab called the 'post-extraction' as 'un-extracted', I am guessing you also mean that?

I observed recovery 100-115% mostly with protein precipitation projects in our lab. My explanation to auditors was that the extracted samples are little bit more concentrated than the post-extracted samples because some protein is precipitated out in extracted samples. While in the post-extracted samples, the measured volume of supernatant from precipitated blank is use to make up a required concentration. Ususally for protein precipitation, recovery is almost 100%. So if extracted is more concentrated than it supposed to be (expected conc.), recovery may cross 100%. However, I normally see similar %recovery across all concentrations.

Regards,
Ladi
Kintan Patel
Junior

2018-11-29 11:48

@ Ladi
Posting: # 19659
Views: 240
 

 recoveries more than 100%

Hello Ladi and Deepak,

The % recovery across all concentration levels (i.e LOW ,MED add High) should be consistent that means %CV should be within 20% across all levels and also you should mentioned the accepted % recovery range (i.e from 30% to 120%) in your SOP and this high % recovery might be due to ion enhancement , sample preparation error etc. and also it is acceptable as per FDA guideline.(limit for % recovery is not mentioned in FDA Guideline)

Thank You,
Kintan Patel


Edit: Full quote removed. Please delete everything from the text of the original poster which is not necessary in understanding your answer; see also this post! [Ohlbe]
Ohlbe
Hero

France,
2018-11-30 18:23

@ Kintan Patel
Posting: # 19665
Views: 216
 

 Origin of figures ?

Dear Kintan Patel,

» The % recovery across all concentration levels (i.e LOW ,MED add High) should be consistent that means %CV should be within 20% across all levels

Could you clarify where you took this value of 20 % from ?

» and also you should mentioned the accepted % recovery range (i.e from 30% to 120%) in your SOP

Why 30% to 120% ? Where do these values come from ?

Regards
Ohlbe
Kintan Patel
Junior

2018-12-05 10:04

@ Ohlbe
Posting: # 19668
Views: 134
 

 Origin of figures ?

Dear Ohlbe,

» » The % recovery across all concentration levels (i.e LOW ,MED add High) should be consistent that means %CV should be within 20% across all levels

%CV for % recoveries across Low, med and high level shall be within 20 %.

» Why 30% to 120% ? Where do these values come from ?

This is just example. You can keep accepted % recovery as 25 % to 125 % etc. in you SOP,but in guideline % recovery criteria no where mentioned but many industries had included acceptance criteria of % recovery in their SOP.

Thanks ,
Kintan Patel


Edit: Full quote removed. Please delete everything from the text of the original poster which is not necessary in understanding your answer; see also this post! [Ohlbe]
Ohlbe
Hero

France,
2018-12-05 10:30

@ Kintan Patel
Posting: # 19669
Views: 128
 

 Origin of figures ?

Dear Kintan Patel,

» %CV for % recoveries across Low, med and high level shall be within 20 %.

Why 20 % ? Where did you take that value from (apart from your own SOP) ?
How do you calculate the CV: take all individual values ? Or the average at L, average at M and average at H level ?

» » Why 30% to 120% ? Where do these values come from ?
»
» This is just example. You can keep accepted % recovery as 25 % to 125 % etc. in you SOP [...]
Right. Then e.g., not i.e.

Regards
Ohlbe
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