Blood Work APS

Quick Question that I can't seem to find the answer to online easily. I figured I would try here since many of you are so knowledgeable.

Can you have APS but never have the blood work to support it.
If you have false positive syphilis test could that be a marker for APS.

Any help would be great.

As always, thanks so much.

Jamie

Hi JamieLea,
It is doubtful that you would be diagnosed with APS without the requisite positive test results:

Based on the International APS Classification Criteria a clinical event (blood clot or pregnancy complications) and one of the following blood tests are required for the APS diagnosis (patients should undergo at least two blood tests, which should be spaced three months apart to show persistent levels of aPL). Commonly used tests include:
Lupus anticoagulant (LA) test
Anticardiolipin antibody (aCL) test
Anti-Beta-2 glycoprotein-I (aB2GPI) test.
www.apsaction.org/about.html

A false-positive syphilis tes CAN be a marker for APS, but not necessarily:

False-Positive Test for Syphilis
In the 1940s, when it was common for people to have premarital exams, doctors realized that some women with lupus tested positive for syphilis. Further studies indicated that 1 in 5 people with lupus had a false-positive syphilis test. The syphilis test of those days—the Wasserman test—was dependant on an antibody found in syphilis patients called reagin. The substance to which this antibody reacts is cardiolipin, so the individuals with a false-positive syphilis test actually had a form of anticardiolipin antibodies. The false-positive syphilis test was the first recognized test for antiphospholipid antibodies, but it is now known that people can have antiphospholipid antibodies without having a false-positive syphilis test and vice versa.
www.hopkinslupus.org/lupus-tests/antiphospholipid-antibodies/

I hope that helps.

Good luck,
Rob

Thanks so much Rob for your help.

Jamie:

I know someone who had Lupus and ITP, and also had repeated blood clots. All APS tests were negative for years. Finally one day, she tested positive for the LA. It is entirely possible that there is a clotting antibody which has not yet been discovered. There was no other way to explain her severe clots with low platelets, although she'd had a splenectomy which can raise the clotting risk.

Oh yes, the false-positive syphilis can definitely be a marker for APS. I had a false positive VDRL in 1981 and ended up with APS Antibodies in 2006 (was not tested before that). No coincidence there. My VDRL in 2006 was flagged as extremely high, so I still have those antibodies.

What's going on?

Here's an update to 2023: "The 2023 ACR/EULAR APS classification criteria include an entry criterion of at least one positive antiphospholipid antibody (aPL) test within 3 years of identification of an aPL-associated clinical criterion, followed by additive weighted criteria (score range 1-7 points each) clustered into 6 clinical domains (macrovascular venous thromboembolism, macrovascular arterial thrombosis, microvascular, obstetric, cardiac valve, and hematologic) and 2 laboratory domains (lupus anticoagulant functional coagulation assays, and solid-phase enzyme-linked immunosorbent assays for IgG/IgM anticardiolipin and/or IgG/IgM anti-β2 -glycoprotein I antibodies). Patients accumulating at least 3 points each from the clinical and laboratory domains are classified as having APS."
pubmed.ncbi.nlm.nih.gov/37635643/