ISTAT new reagent lot confirmation of acceptability
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Looking to see how other facilities handle lot to lot comparison for iSTAT cartridges.
My facility currently uses e-VAS to detect PASS/FAIL and perform 2 levels of QC using the old and new lot side be side. If they both Pass then they are acceptable for patient use. Results are reviewed in RALS.
During our recent CAP survey they suggested we calculate a % difference and have an acceptable limit defined. COM.30450
How does your facility perform lot to lot comparisons?
Thanks in advance!
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We perform all levels of linearity (and QC if not part of the linearity material) and two patients samples. We use the CAP standards for our acceptable % difference per analyte.
We do 5 patient samples with each shipment of our standing order. The lab calls us when they have a sample and we run that sample on our Istats. I have a spreadsheet with acceptable limits and just plug the numbers in there. It's easier for us to do it that way because our lab runs gases and they are right down the hall. It also covers our instrument comparisons so it kills 2 birds with 1 stone.
We run 2 levels of QC on old/new lot and use CAP/CLIA % differences on a simple spreadsheet.
Thanks for the responses! Very helpful.
If you use a spreadsheet do you export the data or manually type? We use 9 different cartridges - it seems like it would be very time consuming.
Would anyone be willing to share their spreadsheet?
My email is woodwars@musc.edu
Thanks, Shea
I'm also interested in the spreadsheet. Thank you in advance!!!!
tcruz@centflhealth.org
If you have multi site facilities, do you all perform lot to lot on all the ISTAT meters in all your facilities? Do you run the lot to lot (POCT Coordinator) or do you have the end users run it? Would also be interested in the spreadsheet.
Thanks, Marilou
My helpers or myself run the lot to lot - I don't consider this part of the routine monthly (or however often you perform) QC. We only do the lot to lot on the spare meters we keep in the lab.
We just hand enter into the template for the analytes that are on the cartridge we are doing lot to lots on that time and save under the new cartridge lot #. I've attached examples. We have 8 different cartridge types but we don't order new shipments that often. Maybe a couple different cartridges every 2 weeks? So it's not time consuming.
The limits are taken from published standards - here's a link to one site:
https://datainnovations.com/allowable-total-error-table
For the analytes that have say "3SD" as the limit, I calculate that from the SD of one of the recent PT challenges from a sample near that value. That is how I was taught by a Chemistry technical specialist years ago.
It seems we're all doing something different, none of which I as an inspector would consider wrong. Ultimately, it's up to the medical director - some are ok with less and some like numbers. Honestly, my director is not very invested in POC so I do my best!
Danyel,
Thank you for sharing it!!!!
Thanks for the feedback and sharing the forms Danyel. Btw, is it also a requirement to do linearity for new lots of ISAT cartridges?
Danyel,
Thanks this is perfect!
Shea
That is not a CAP requirement. You only need to "confirm that the use of new reagent lots and shipments not not affect patient results." The recommended sample is patient specimens, to obviate the matrix effect, but can use other materials. So the linearity kit could be used; see COM.30450. The linearity kit is used every 6 months to validate AMR (analytic measurement range) and definitely does not add value to be done with every lot/shipment as a lot-to-lot confirmation.
This is from ISTAT technical bulletin. Does other accrediting agency requires linearity for new lots?
Linearity is not required by Abbott for new lot number of cartridges.
You are required to run QC on new lot, new shipment, monthly ( per our IQCP) or troubleshooting.
Joint Commission do not even require calibration every 6 months because the linearity of the cartridge will not change.
i-STATs are manufacturer -calibrated.
Linearity is only required initially before a new analyte/ cartridge/analyzer is put into use.
CAP require calibration verification every 6 months.
Correct me if I'm wrong in my interpretation of this and per my IQCP. I currently run QC on new shipment of Cartridges or if my temperature fluctuates on the storage of cartridges. I do not do Lot-to -lot as it is not required as long as you evas is current and up to date. Your result are compared to a set requirement from Abbott that is what the evas is for. Therefore lot-to lot is not required. You are proving you're QC is working when it is compare to the evas. Because of the stability of the ISTAT as long as the controls work on the new shipment and the temperature ranges are met. You should not have to do lot-to-lot testing. But you must acknowledge that QC was valid and within the ranges determined by Abbott.
We do Lot to Lot because of CAP, not because it is required by Abbott. However, we do not run the old lot with the new lot, we simply compare the results from the new lot to the results we obtained when we ran the old lot on the previous shipment and compare them on a worksheet. We use a limit of 10% defined on our sheet, but I suppose it would be even better to use the TEA as defined per analyte - that just might be a pretty big number for some analytes (ACT) and I want to detect if there was a major change to the range. We also use EVAS so it does feel like a waste of time. CAP regs really don't blend well with iSTAT, they are getting better though! In the olden days we had to do a lot more QC than we do now.