LH surge leading to false positive PG test?

[WantsALittle1]

An NP told me that it's possible for LH to cause a false positive pregnancy test because LH and hCG are biochemically similar. She cited the fact that to stim ovulation, they inject hCG, not LH, and it works just as well.

Is this actually possible?

I know OPKs often go positive during pregnancy, but I didn't think it worked the other way around. I suspect that I've had 2 CPs in the last three months, but the NP seemed fairly certain that my faint positive tests (she looked at them all) were being caused by the trailing end of my LH surge and not by hCG.

 

[Blackrain90]

From everything I have read, ov tests can pick up hcg but not the other way around.

 

[linz85]

From what I've read, HPT's only pick up HCG and nothing else. OTK's pick upo both HCG and LH so yes they can often tell you your pregnant if you didn't know ( like me) x

 

[LoraLoo]

No, hpt picks up hcg only.

Opk pick up lh and hcg.

 

[lisap2008]

Your doctor is correct that HCG and LH are sister hormones, which is why you can get a + OPK from HCG and HCG is used to trigger ovulation however I have never experienced a pregnancy test to pick up LH hormone in 7 years of TTC.

 

[Tripledagger3]

Yah I agree w the other posters, u have it backwards. Lh will definitely not show up as hcg on a hpt

 

[MustangGTgirl]

Yes an hpt can pick up lh depending on the brand. The pink wondfos give me a faint line every time I am ovulating, thats how I test for ovulation! I suspect that a lot of the so called evaps women get with them around their periods are indeed an lh surge that the wondfos pick up.

This is a thread I made a couple of years ago when I first got a faint line in the middle of my cycle. I didn't know what was going on, it was day 15 of a 28 day cycle (my ovulation day). There are other women on the thread that confirm that hpts do pick up lh.

https://babyandbump.momtastic.com/pregnancy-tests/1889993-8dpo-afternoon-frer-there-line.html

 

[WantsALittle1]

It's fascinating that this has happened to others, and I do believe it's possible so I'm not denying it by any means. However the main reason I disagreed with my NP about my case in particular is that I had BFNs 4-5 DPO, then BFPs 6-7 DPO, and then fainter BFP on 8 DPO and BFN from 9 DPO onward. So the pattern of tests didn't fit my LH surge, which had already tapered down to baseline by 3 DPO, according to my OPKs. If the BFPs were caused by LH, then I would have expected my 4-5 DPO tests to be BFP too. When I brought this up to the NP, she suggested this idea of a random 6 DPO LH surge causing the BFPs, and I just thought that didn't sound right, and that it was much more likely to be an early/tubal implantation. Does anyone know if a 6 DPO LH surge exists?

Just for the heck of it, took a Wondfo (CD 14, LH is surging today) and it's BFN for me.

 

[Blackrain90]

Yeah I'm sorry but your NP sounds like she is fishing. Negatives after your surge, followed by positives and then negatives is a textbook chemical. I have never heard of a second surge.

 

[Powell130]

That's false. HPTs ONLY pick up HCG. It's the OPKs that pick up both.
A fade in/out pattern on a HPT before AF woud be a chemical pregnancy

 

[WantsALittle1]

Blackrain, I agree. I think the reason she was fishing is because a 6 DPO BFP is supposed to be impossible. She couldn't explain it so she started talking about the LH surge thing. I brought up the possibility of a tubal implant but she said no. So most likely I was somehow off on ovulation date (even though I charted?)