plasma and serum - (Sep/16/2009 )

will it make any difference if i use serum/edta plasma for hscrp (the kit sample requirement is citrated plasma)? but in my writing, i used serum for other biomarker.

wntiong on Sep 17 2009, 02:39 AM said:

If the instructions supplied with the kit say to use citrate plasma you MUST use this. This is for a number of reasons:

1. Assays are prone to "matrix effects". If you choose to use a matrix (EDTA plasma/serum etc) not specified by the developer of the kit you may alter "calibrator commutability". This is the constant ratio of the readout signal between samples and assay standards containing the same amount of analyte. More simply, if you use an inappropriate matrix you cannot rely on your assay being calibrated properly.

2. If you chose to use serum as matrix you may get changes in your analyte level during the clotting process. For example analyte degradation due to protease activity.

3. Your analyte may not be stable in serum/heparin plasma/EDTA plasma during transportation (from patient to lab).

The assay manufacturer has probably spent a considerable amount of time optimizing "preanalytical variables". Alter them at you peril...

Hope this helps

If you are using a 510(k) approved kit (approved by FDA) for reporting clinical patient sample results you must use the sample type indicated in the instructions.

If you are doing research then refer to the above reply. Note: all the info in the package insert was done using the matrix/sample specified in the instructions.