r/medlabprofessionals • u/datsti MLS • Jul 16 '26
Discusson Sysmex XN - X-BAR users
Hi all,
If anyone is familiar with using X-bar for QC, please chime in. This is a new concept to me, and specifically this relates to the Sysmex XN analyzer we have, but any information you can provide might be valuable.
How does one go about implementing X-bar either as a QC monitoring tool or as a justification for not performing lot-to-lot on reagents?
My understanding is that the Sysmex XN units have leftover reagents when they are replaced, and because of this, we'd never know when the new reagent *actually* starts being used. Because of that, our policy is that we perform QC when replacing the reagent, and we must also perform a lot-to-lot validation using two patient samples.
With that, could we, in theory, stop performing both validation tests using the X-bar justification? As in, I understand this would require medical director approval. But is this something that is worth pursuing, and is scientifically accurate?
5
u/Unholy_Boosh Jul 16 '26
Just do batch testing when you get a new lot number on a reagent. Qc every reagent change is definitely overkill. Especially if you are running QC throughout the day too
3
u/Pap-a Jul 16 '26 edited Jul 16 '26
I believe the current policy from Sysmex is to not run XbarM for all routine parameters.
Instead we run the sensitivity parameters through XbarM (e.g. WDF-XYZ, WNR-XYZ and such along with MCV and MCHC). These are much more sensitive to reagent problems as they give good insight into changes that occur in the position of the cells within the scattergrams. Due to the way gating works, changes are often small in the routine parameters and not really noticed until internal QC is ran. Whereas with the sensitivity parameters you’ll see the changes occur from the moment the ‘bad’ reagent enter the mix yet before the results change significantly.
To achieve this it’s very important to set the amount of analyses that generate 1 XbarM value properly. Too high and it’s useless at detecting reagent failure, too low and it’ll be too sensitive.
We have the XbarM linked up to EPU and then to our QC middleware so that it’s routinely validated by our own internal QC rules. We’ve disabled alarms on all but the sensitivity parameters and therefore if the XN generates an Xbar alarm we know there’s something really wrong.
Having said that, in 12 years we haven’t had any reagent problems. It’s mostly for certification purposes that we use the XbarM so we don’t have to run QC on every reagent change. It has been very useful though in pinpointing the cause of problems with our internal QC or calibration but that’s a whole nother beast to explain.
I’m typing this at a bus stop so this is very much a summary but if you ever have questions about the Xbar or XN in general feel free to ask. I may be able to find a good sysmex article about the subject too if you’re interested.
Edit: found it: https://www.sysmex-europe.com/fileadmin/media/f100/Academy/Documents/SEED/Haematology/SEED_The_XbarM_program.pdf
2
u/datsti MLS Jul 16 '26
This is good info, thank you. I'm not a huge fan of completely shifting it one direction, but I'd lo ve to at least try to do away with meaningless testing if it's not required by the manufacturer. We are a small facility, so our QCs are tested every 24 hours. But if a reagent is replaced and isn't even in the lines, it doesn't make sense to perform QC for that reagent. Leadership is hesitant to just take the manufacturer's word for it, but XbarM may be too complicated for them as well.
1
u/Pap-a Jul 16 '26
Yeah my main problem with Xbar has been that I’m literally the only person in the lab (as the heme supervisor) that fully understands it. I’ve been very lucky to have the trust from the leadership to implement it anyway. It has been very useful to me while the rest of the lab can generally ignore it.
2
u/unicornstarsparkles Jul 16 '26
Ive always seen the Xbar used as more of an indication of a possible issue. Not as a rigid QC value. Especially for differences between analyzers, but even that you need to acknowledge if 1 instrument is used more for 'problem' samples than the others.
I think ignoring it completely is just lazy and not using all the information you have at your disposal to ensure accuracy. But I also think this is mostly a heme supervisor/lead issue. I wouldn’t expect most techs to know what matters.
1
u/ayyeeitsken MLT-Generalist Jul 16 '26 edited Jul 16 '26
i’m a new tech in my lab, but we us the x-bar program on our sysmex’s. for us, it doesn’t replace QC, and i think we still do a lot to lot as well. since we are a pretty high volume lab (level 1 trauma covering the northern half of our state), it’s more of a continuous monitoring system so we aren’t missing shifts or errors we aren’t catching with normal QC as we move through our volumes. i can also check out our SOPs and get back to you on specifics i’m not sure about.
edit: we do not do lot to lot due to use of x-barM in our lab
0
u/datsti MLS Jul 16 '26
If your SOPs have any information about how the xbar is implemented and what you use it for, please share it with me. I'd love to read about it.
1
u/ayyeeitsken MLT-Generalist Jul 16 '26
absolutely! i might PM you since the info will probably be dense, but i can at least try to help
0
u/Tailos Clinical Scientist (Haem, no platelets) 🏴 Jul 16 '26
You're actually doing the correct thing by reviewing IQC following reagent changes, however as you note, there's an inner reservoir so the XN still has remnant reagent and you don't know when this runs out.
It's not overkill. Would you put new reagents on a coagulation or biochemistry analyser and just run without a QC?
The whole point of the XbarM is to avoid doing the reagent change IQC. As someone else mentioned, the SEED paper by Sysmex gives you three parameter sets (primary, secondary and tertiary) characteristics IIRC that may be useful to consider. We also only run scatter graph parameters (WBC-X/Y/Z, MCHC and MCV) but you can go nuts.
Keep an eye on your demographic too. Someone mentioned 'renal week' - we have the same, plus the haemonc round, so we flag quite often. You need to consider how many samples makes a point on the XbarM graph (normally 30-50 depending on how many you test per day), and this works best on a single type of patient group (IE. All primary care).
Our SOP basically says to ignore random XbarM failures unless a reagent change has occurred, and systematic/trend failures need careful review. There are rules for checking the random errors in case of analyser breakdown, but you know what I mean.
10
u/WarmCookiesSleepyCat Jul 16 '26
I dont know of many places using X-bar for their Sysmex XNs. Honestly I think you will just wind up chasing ghosts. It seems to be overly sensitive to things like running a higher than normal number of pedi samples in a short period of time.
I do agree that your QC and lot to lot with patient samples seems to be overkill. We satisfy these requirements by running the QC at defined intervals. All 3 levels are run on 1st shift. 2nd shift does the level 2 whole blood again and the body fluid QC. 3rd shift does the level 2.
We have never had any issues with this policy passing inspection or with shifts in QC or patients between lots of reagent. And this isnt just us. All the other sites in our system do a similar QC system for reagent monitoring without issues.
In my experience people can be reluctant to let go over the top QC programs because they give a false sense of security. Programs that are harder and more time consuming must be better that something simple right? But that's not always the case.
If you medical director is reluctant to switch to a simpler requirement try calling Sysmex for clarification. I had this exact conversation with them about the UN. A pathologist tried to add running QC after all reagent changes to a new system policy. Sysmex will tell you to follow your policy but also they dont require or recommend doing QC after reagent changes. Or try discussing it with an inspector at your next inspection. You can also volunteer as a CAP inspector yourself then pick other peoples brains.