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Factor X Chromogenic Assay (FXC): I have this. It renders my “true vein value INR “ one full number lower than it actually is.

Factor X Chromogenic Assay (FXC): I have this. It renders my “true vein value INR “ one full number lower than it actually is.

This apparently is why I’ve been reclotting.

I don’t understand it that well yet. Please look up

It’s a lab out of the USA that manufactures this assay. ( blue top draw .)

A perfect example I’ll give you is from Monday the 27th of November.

( I took my coagucheck meter with me so my finger prick was done at same time as vein draw at hematologist’s office.)

Finger Prick value: 5.7

Vein value: 4.94

Chromogenic 10 assay Factor 10 (CFX):16

Actual adjusted INR vein value 3.8 by

This is absolutely critical!!!!!!!!!!!

I was told to put this CFX on my standing order along with my INR. Have it drawn often. At least three times a week. It’s a three day send out.

I’ve been dosing myself- I do NOT recommend this. I have not had good/ dependable contact with my regular heme, who who did not order this GP has had poor luck in past with him not returning calls.

With finger prick values, im on average, about .5 less in vein than finger prick. So now I’m taking one full point off further.

I was in full bowel ileus starting Friday night and clotting I’m superficial veins on top of thigh ang bruising. I showed 4.1 by coagucheck Saturday afternoon.

I did the math- increased my warfarin by 1/4 mg, and started injecting heparin...

I’m shooting blind... God help me. Or perhaps someone here who knows about this?!?!

I see my GP Wednesday. I’m very ill.

( I’ve noticed I feel my best when FP value is 5.5. This is now my goal taking into consideration these two adjustments.)

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Hi there,

Have you talked to some Hematologist who understands lab values and Lupus Anticoagulant. Roche perhaps? Prof Hughes perhaps or APsnotFab what she says.

It sounds interesting and it could be a solution but I would not dare to do it on my own!

Please talk to some of your Specialists before you go that high.

Your GP will not understand about that I am sure.

I also feel well at 5.5 and then I am on an vein INR of 4.2. When the INR is high the difference is bigger between fingerprick- and veinvalue.

I could not read it as it was almost not visible. Will try another way.


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I’ve had the discrepancy do a little bit of both, but in general, yes. That’s right.


Kerstin, I googled this :

Factor X Chromogenic Assay (FXC)

and found the article in pdf format.

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Sorry it’s so blurry. That’s why included the name to lab company. Attachments on HU are often terribly blurred.


The hematologist I consulted with last week ( Dr Guzley) is the one who ran the test, Kersten. To see if I needed to suppress the antibodies with the cytoxan chemo therapy. The answer in his opinion was no. There may be another reason to why you are clotting. ( by the way he may be good in this one area only but bad in way too many others... I don’t know what my main heme thinks about all this yet.)

He called me and gave me these results. ( I would never put this on forum if I did not have confirmation from a hematologist. I would not even have known about this.)

He told me to have my regular hematologist add to my standing INR order. He called my main heme- but I haven’t talked with my main heme yet.

That would be nice if I could. I called his nurse and she knew nothing of it. I explained the numbers game. I told her I planned to keep INR at 5.5. She said she understood- but Dr Holahan ( main heme) was off on Friday- when I called- and he was not on call over the weekend. Another doctor- who I have never met- was.


Typical.... sorry you’re still dealing with this dilemma and now especially alone. I’ve never heard of this blood test either but I am going to look into it, you know how I am! Best of luck to you with getting your doctors communicating together, Cindy


Read the article and I don’t get it? Who is on first, this is so confusing I don’t understand how you came up with how to figure out what number you really are. Best of luck. I hate to ask but what are you doing now? Has Dr Holahan finally called you? Cindy


Nope. Just keeping finger prick value at 5.5 to 6.0

My GP was going to call him yesterday or today. I meet with my GP Thursday. I told Holahan’s nurse to alert Holahan to please take my GP’s call!

Apparently Holahan just can’t posdiblt see me until Jan 3rd the nurse said... that’s why I said... then just have him tell my GP how to manage me - that’s fine until then. Something- anything!

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Kelly, why are you alone? This is unacceptable? Where are your doctors? Forgive my ignorance, but your story is shocking!

With good wishes,



I’m shocked as well. Welcome to Texas. Welcome to America. ( with regards to APS. ) The story gets even worse. This doctor tried to tell me he did not even believe I had APS when he say me on the 27th! ( then how does he explain this test)

The clots?

It’s because I had gone sero negative and it was in my chart from a previous doctor accounted with his state wide group called Texas oncology. My records are in his system. I had been assigned a heme in the hospital through that group. I had then gone sero negative under his care-I went to dr Erkan in NYS who said because my antibodies were not “ persistently HIGH I did not have APS. He told me my clot must have been “ somehow provoked.” This Hospital heme then took Erkans dismissal of Hughes and dismissed me as a patient- but did not take me out of computer system if Texas Oncology.

My Rheum and GP knew better. They sent me to London Bridge. Kept monitoring and prescribing my warfarin temporarily. ( within three weeks I was in London.)

I went to London Bridge- saw Natasha Jordan- and professor Hughes kindly sat in with her in my office visit with my daughter and I, while my husband stayed behind and worked and looked after our son who is now 16. He recently was “ diagnosed” with additional antibodies” - the phosphotydel- serines.

He had frequesnt migraines- my mom was a classic clotter, pre eclampsia with pregnancies, PE’ s migraines-ets, died of complications.

Any way... last Monday was a nightmare. ( by the way he had never heard of Dr Hughes, which is fine. I understand that. As long as he understands the disease .)

I though we had a good consult! I did tell him my antibodies are positive again- I did not go into much detail at all. I wasn’t there to confirm a diagnosis! We are SO FAR BEYOND THIS!!!

When he called me with this result, he told me thought my abdominal symptoms were due to migraine...

I showed him my clinic letter from London Bridge... mildly positive antibodies... it served as a guide line for my history.

There was a blog from April from Professor. Patient if the month- perfect storm. It was with my clinic letter. He read it. It happens to be me. The point is I have horrible neuro symptoms. Confirmed epilepsy was only slight mistake professor made, but I’m dr Jordan’s actual patient. It’s the gist we are after.

“ is this origional? There are a lot of misspellings.”

I assume... I said. I thought nothing of it.

Turns out he though I was lying! That I had forged the blog, and probably the clinic letter also.

He told me he had called London Bridge and was going to “ verify that dr Jordan thought I had APS.”

I asked him... “ do you question my diagnosis from Dr Hughrs?”

He said, “ yes. I do. And I called all your doctors and told them so. I think you need psychological help.

I just can’t belive it.

He’s going by Sidney revised criteria and no sense.

Increadibly damaging... I’m sure my doctors will rally by my side.

I’m going to post my clinic letter just because I feel I have to but right now I have to go to hospital to get a vein draw.


Oh Kelly just saw this part now, this is shameful what an a$$. I feel as I’ve said that to you in another post somewhere. Best of luck. Too bad you can’t reach DrHughes yourself to get advice on this new lab information, Seems very much warrantedDr Hughes needs the emergency “bat phone”. For those of you outside of the US it is an emergency phone to call a superhero when emergent situation needs to be handled.. you call the number and the super hero responds... Kelly, to the bat phone! Best of luck, love you honey, hang in there🧐


Oh, this sounds so familar. I live in California & have had similar problems. I tested aero negative after being positive. They told me APS went away. Refused to treat me & said I had progressive MS. Well to make a long story short, they are always wrong in my diagnosis & treatment. If it wasn’t for Professor Hughes I wouldn’t be a live today. The US drs. Rely on their blood test & other test, they don’t look at the total picture. As far as the blood test-Professor Khastma told me they only test for 2 proteins when there is over 60 proteins. If they tested all of them they would probably find a positive protein. It is not cost efficient to test for all of them. Believe Professor Hughes & find a dr. That will follow what he says. Good luck.



Oh, Kelly, this is awful!

Is your family there? Sometimes bringing in family in these situations--particularly male family--can help.


He was with me at the appointment with this Dr Guzley- like I said. We thought the appointment went well enough . Looking back on it we now realize some of his questions / comments were a little puzzling.

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It is horrible that you have to go through this. You know so many things now. I am afraid that you will be quite exhausted by all this. This illness is really something special to go through for some of us.

Can you rest a little after you have got the vein-draw done

Big Hugs from Kerstin!


I'm lost for words.......The arrogance of some specialists! (I came across some in my journey to diagnosis and treatment) just makes the mind boggle.


And then boggle some more.


Oh my. Oh my. Oh my.


My lovely Texan doppelgänger!!

I’m asking my haemo about this tomorrow. I’ve printed it off and tried to understand it as best I can.

Have you had it tested again yet? X


He just said I had this and I had to have it tested more than once a week. From now on- it was already confirmed by multiple clotting with INR so high.


Yeah that’s what I’m asking. Have next test results come back with exact same difference? Or will it be like our coaguchek machine with a variable difference which will make it even harder to manage?


Kelly, I see you asked if I have tested again to see if the value has changed.

My GP in my hometown of Kerrville, Dr Stevener, is supposed to call my main hematologist , Holahan- either yesterday or today. ( Monday or Tuesday). I tried lat Friday but Holahan was gone for day- I spoke to his nurse instead.

I don’t have that CFX put on my standing order with my INR yet at Hospital here. My GP is going to have to do that. I am waiting for that to happen! I don’t know whay it has not yet happened...

I have a meeting with Stevener on Thursday afternoon.

So I’m still just guessing! I’m keeping finger prick value at 5.5-6.0.

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Go to bed now - I’m just getting up ! X


And... I met with Stevener nurse Friday and we made a small list of questions for dr Stevener to ask dr Holahan when he calls:

1. Exactly your question! Will the value be always fixed at 1? Or will it be labile?

2. Is this a reflection of the actual “ lupus Anticoagulant ANTIBODY “ itself? The wording from that lab is slightly misleading. “ a component of the Antiphospholipid syndrome “ I think is how it was worded...

Steverners nurse is actually a PdD researcher. I’m thinking she and I might call the lab together.

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I am so sorry you’re going through all this. Good luck Kelly.

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I called the lab. I found out it’s only about 5 years old, this test.

Each state has its own lab- or a few. The one I cited is in Minnesota.

The woman I spoke with could not exactly answer my highly specific questions, but from what I could gather, I do believe this test is a “ work around” if you have the lupus Anticoagulant Antibody specifically. Here is what she said:

1. The test works for people who have a certain artifact in their blood . It is called Lupus Anticoagulant. They are what we call LA positive.

2. This test is a measure of pro time, not INR because patients with LA have a different pro time than normal INR patients and it need to be measured differently.

But she did not understand the question, is it specifically the lupus Anticoagulant Antibody? She said “ I’m not a hematologist... I’m not exactly sure. All I know is it’s Lupus Anticoagulant.”

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