Mithu
☆    

India,
2018-09-06 10:27

Posting: # 19244
Views: 880
 

 applying correction factor to unknown samples due to stabilization [Bioanalytics]

Hi All,

I request you all to correct me if my below mention understanding is not correct.

As per my understanding, whenever we add any stabilizer in study samples immediately after collection of blood samples or after getting plasma separated from the blood we add the stabilizer, we should apply correction factor to the obtain unknown concentrations.

This factor needs to apply only to study samples not to CC & QC prepared. The rational what i believe for this is, unknown samples get little diluted due to addition of stabilization solution and it will not produce true value. Whereas the CC & QC which are also stabilized but here we have known concentration, hence correction factor is not needed to apply because we have % nominal for the acceptance or rejection of the same.

Hence the correction factor applies to get the correct or true concentration of unknown samples only.

Regards,

Mithu
Ladi
☆    

Thailand,
2018-09-06 11:53

@ Mithu
Posting: # 19246
Views: 773
 

 applying correction factor to unknown samples due to stabilization

Hi Mithu,

» As per my understanding, whenever we add any stabilizer in study samples immediately after collection of blood samples or after getting plasma separated from the blood we add the stabilizer, we should apply correction factor to the obtain unknown concentrations.

Not sure if that is necessary if the ratio of plasma to stabilizer in CC/QC and study samples is kept the same.

For example,

- for study samples I added 100 uL of a buffer for every 1000 uL plasma collected before freezing.
- for bulk spiked CC/QC after spiking to desire concentration, I also add 100 uL buffer for every 1000 uL bulk spiked plasma before freezing.
-for analysis, I aliquot an equal volume of CC/QC and study samples for extraction. The stabilizer added should not change the true value. Am I right?

But adding the stabilizer directly to blood before plasma separation should be more complicated and I have never done it.

Regards,
Ladi
Mithu
☆    

India,
2018-09-06 12:52

@ Ladi
Posting: # 19248
Views: 762
 

 applying correction factor to unknown samples due to stabilization

» For example,
»
» - for study samples I added 100 uL of a buffer for every 1000 uL plasma collected before freezing.
» - for bulk spiked CC/QC after spiking to desire concentration, I also add 100 uL buffer for every 1000 uL bulk spiked plasma before freezing.
» -for analysis, I aliquot an equal volume of CC/QC and study samples for extraction. The stabilizer added should not change the true value. Am I right?

Actually i don't know. i have a method in which CC & QC's are prepared in acidified plasma, where in subject samples after the separation, stabilizer added to the samples. In that they have applied correction factor.

This is the point where actually i need to understand the correct practice.

» But adding the stabilizer directly to blood before plasma separation should be more complicated and I have never done it.

i agree for the direct collection of blood with stabilized solution would also a point for understanding of correct process.

I can only comment that, not applying correction factor to the CC & QC is because it is containing known amount whereas in unknown samples little dilution to the samples will not be considered as true value.
Activity
 Thread view
Bioequivalence and Bioavailability Forum |  Admin contact
19,604 posts in 4,158 threads, 1,340 registered users;
online 7 (0 registered, 7 guests [including 5 identified bots]).
Forum time (Europe/Vienna): 17:25 CEST

Nothing in the world is more dangerous
than sincere ignorance
and conscientious stupidity.    Martin Luther King, Jr.

The BIOEQUIVALENCE / BIOAVAILABILITY FORUM is hosted by
BEBAC Ing. Helmut Schütz
HTML5