Subtherapeutic ACT values after standard heparin dosing

To the sites that have reported an issue to Abbott, when did you receive your cartridges?  Our last 'good lot' was received in October 2025. All subsequent lots were received late December to date. Wondering if the extreme weather conditions have compromised the integrity of the cartridge.
Thank you.

I use the iSTAT ACT-Celite. I did have a patient about a week ago that the Cath Lab inquired about. They ended up giving 3 doses of Heparin (for a total of 11000 units) and didn't see much of a change in the ACT as well. After I reviewed QC and didn't see any other patient with this problem, I did some research on this patient, and she did have the same circumstances in April 2025 ( she received 12000 units then with 3 ACT's performed) for a previous procedure. We were attributing it to, that she is probably a Heparin Resistant patient. We get them every once in a while. Does anyone else see this on their patients?

There are cases documented about patients having Heparin resistance.  I suggest you google to get the jest but according to studies it is due to ATIII deficiency or can also be attributed to systemic reasons.  Things like Inflammation. sepsis or types of drugs interventions according to iperfusion.org.
We experienced this a couple of years ago and there was a gentleman in Abbott who is well versed in this, but I cannot remember his name.  I suggest keeping the tickets open to see if they had a way to mitigate the problem and come up with a recommendation on how to handle it.  It is supposed to be a less likely of an event within patients, but it seems more people are becoming Heparin resistant.   I am not the expert just sharing what I was experienced.

I had to open a case for this same issue and I'm wondering if anyone has heard from Abbott after sending cartridges back for testing? The lot we are using is R25342. Our pharmacy has sent Heparin back to the vendors for testing as well. I was able to verify that the Cath lab is waiting 15 minutes before drawing samples after the bolus is given. 

Hi everyone, sorry to bother you again ,  we are still experiencing an issue with the ACT-K cartridge, almost 3 months later. For those sites that submitted a complaint with Abbott, are you still experiencing low ACT with standard heparin dosage?  Have you ruled out Heparin performance?

Not sure if this will help anyone but Our facility was having this same issue, and this is what we did to troubleshoot besides running all of the quality controls and calibrations. Our pharmacy had changed to a more economical brand/dosage. When they reverted back, the issue seemed to resolve itself.

The Heparin products that were being used when the issue started:
Sandoz; 10,000 USP unites/10mL
Meitheal Pharmaceuticals; 10,000 USP units per 10mL
Hospera; 10,000 USP units per 10mL

Replaced with Sandoz 5000 USP/mL and the ACT results were satisfactory. Our physicians felt that maybe the 10,000 units were being diluted out too much. 

We have been having the same issue at our facility. We have had 7 cases so far from both the Cath labs and the OR. Multiple different operators, multiple different device serial numbers, and different lots of cartridges. The most recent lots have been R25295 & R25326. Our Pharmacy has also changed to a couple of different vendors for heparin, and we are still seeing this happen. We have opened an investigation with Abbott, which has been open for about a month now, but we have not received an update yet from Abbott. Like others have mentioned, we are only seeing this with a few patients. Both of these lots of cartridges had been in use for about a month with no reported issues, and then we began seeing issues. We have been keeping a spreadsheet that is shared between Nursing, Pharmacy and POCT updating with patient, heparin, and ACT information as each case arises, then we are sending that info to Abbott. Hopefully Abbott will be able to tell us something soon. 

How have you all been looking at your data to determine if this is an issue? I pulled all of our results since January 1 but am not sure where to even begin trying to determine if we are seeing this issue on our end. 

Our Abbott rep told me yesterday that they have tested over 1500 cartridges across multiple lot numbers and have not had issues. The cath lab started reporting issues in January. Its not every patient or same procedure each time. We have had 7 patients that have had some issues reaching therapeutic levels. Ive had to rely heavily on the cath lab to let me know what patients they experience issues with. 

This topic came up before on this platform.  You might be dealing with patients who have formed a resistance to Heparin.  I pulled this from the search I made, and this is what I found.

Heparin resistance (HR) occurs when patients require unusually high doses of unfractionated heparin to reach target anticoagulation levels, commonly defined as requiring >35,000 units/day or >30-50 units/kg/h, or failing to achieve adequate activated clotting time (ACT) during cardiac surgery. It is often caused by antithrombin (AT) III deficiency, high heparin-binding protein levels, or accelerated clearance. National Institutes of Health (.gov) +3

Common Causes & Risk Factors

Identification

Here is the hyperlink: https://www.google.com/search?q=Heparin+resisteant+patients&sca_esv=f6b88a89bb20681d&source=hp&ei=4xqfaZcqoMKQ8g-SpoSRAg&iflsig=AFdpzrgAAAAAaZ8o80jnysIAVMuWM0KoCS_5Tkr5VTg7&ved=0ahUKEwjXp4mAgPWSAxUgIUQIHRITISIQ4dUDCBY&uact=5&oq=Heparin+resisteant+patients&gs_lp=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-2AbIHBDE3Ljm4B5QTwgcHMy4xNC4xMMgHSoAIAA&sclient=gws-wiz

If you have a patient with resistance to Heparin (I and a sister hospital had several cases) over several years where the patient's ACT-K results were low while having an appropriate amount of heparin was given in a Cath case.  Also, my understanding is inflammation can also affect the ACT-K results, but these are in low to rare cases.  It's not necessarily the cartridges are bad is what i am trying to say in a poor way.   

We are seeing the same issue, ACT results not reaching therapeutic levels after heparin dosing/bolus.  We have multiple lots and multiple hospitals in our system.  Abbott just stated, "Abbott Point of Care is aware of issues impacting certain ACT testing. We have a team working diligently on this."

I work at the same organization as Delia Henderson. We had a meeting with Abbott and they are seeing complaints come in from about 5% of their customers. They have been doing extensive testing and haven't found any issues with specific lots of cartridges. In their testing they are achieving expected results. We are partnering with them to send in lots of heparin that we are seeing some patient's have issues with. To reiterate it's not all patient's that are being affected. We are sending them 3 different brands of heparin to test against the cartridges. They are looking into potential interferences that could be in the heparin brands. We have sent them back boxes of ACT lots and heparin vials to help with the investigation. Lab is working with pharmacy to answer the questionnaire on the specific patients we are seeing being affected. They realize that some customers could be having issues and not calling it in. The more information and data they have the faster the investigation will be completed.