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ELISA kit past after expiration date


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#1 Era

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Posted 15 June 2011 - 12:25 AM

Dear all,

I am new to ELISA. So I feel a bit stupid when it comes to this topic.
I have a task to measure HIF-1 α in neutrophil cells. We have kit for HIF-1 α measure in nuclear extracts in laboratory, so I want to start my experiments. But this kit was in laboratory for a long time, it past its expiration date. I know thatís very bad. But, since I have never done ELISA, I want to make an attempt with it. Is it possible to get some normal results using a kit after expiration date? Or I will be just wasting my time and I should throw this kit out?
Hope You can help.

Thanks.

#2 PAO_ahac

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Posted 15 June 2011 - 05:04 AM

Since you are new to ELISA why not practice with the expired kit?

First just run the dose response curve and compare the results to the package insert suggested values. If the kit includes controls OR if you have a set of controls from another manufacturer you should run these...IF THE CONTROLS are within the ranges specified then the kit is still usable to some extent.

Kits are expensive so go ahead and run the curve, controls and samples...it will be good practice for you.

#3 Ben Lomond

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Posted 15 June 2011 - 03:44 PM

Elisa kit manufacturers are in the business of selling ELISA kits, so expiration dates are a good thing to have, if it means that expired kits are thrown out and new kits bought. Generous margins can probably be added to most expiration dates if you are not working in a regulated environment.

Coated plates, if stored properly and remain sealed have no reason to decay.

Standards, if lyophilized, and stored properly have no reason to decay, in solution at 4 degrees depends upon the antigen, -20 would be better, -80 should last indefinitely.

Conjugated antibodies are probably the weak link, stabilizers are often added, but these can be variable.

Substrate can also be variable.

If your kit is no more than 2 x the regular stability window (date from manufaturer to expiration) then you are probably OK if all components have been stored appropriately, 3 x the regular stability window, I would be concerned about some components and use the kit for practice only.

If you want a more detailed opinion, let us know the kit and manufacture date.

#4 Era

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Posted 17 June 2011 - 01:18 AM

Thanks for advises.
I have RnD systems kit for active Hif-1 alpha. It expired on 5 of november in 2010.
I think one of the problematic thing is that this kit doesn't include standarts. So I only have samples to try with.

#5 Ben Lomond

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Posted 21 June 2011 - 03:54 PM

Thanks for advises.
I have RnD systems kit for active Hif-1 alpha. It expired on 5 of november in 2010.
I think one of the problematic thing is that this kit doesn't include standarts. So I only have samples to try with.


I suspect the kit will be good and give you some sort of OD response, albeit it may be a little on the low side. If you have a known positive control, dilute this serially (16 serial dilutions for example) and run this as a standard curve and express the results of your samples relative to the dilution of the known positive control. Keep multiple aliquots of the known positive control at -80 as a reference if you need to go back and compare with future samples. Perhaps run a few of your standard dilutions at the beginning and end of your samples in addition to your 'curve' as quality controls (to check for drift and precision etc)




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