labs on PIH patient

RNLaborNurse4U · Jan 1, 2012

I'm a new L&D nurse and had an observation patient for possible PIH/pre-eclampsia. All of her labs came back normal except fibrinogen & d-dimer which were elevated and we were doing a 24 hr urine. Her BP's were normal (although high in the office) and physical assessment negative. I showed my charge RN the labs and she suggested I let the OB know. When I called, I was told that an elevated fibrinogen was a good sign and that the d-dimer was really irrelevant. Can anyone explain why?

Fibrinogen will normally rise during pregnancy. It's not unusual to see it above 500. It's when it drops during pregnancy, usually below 300, that you need to start worrying. A drop below ~300 could indicate that fibrinogen is being used to form a clot, from a partial placental abruption (which a woman with PIH or preeclampsia is at increased risk for).

D-dimer is a pretty useless test during pregnancy, because it can be elevated for many reasons.

RNLaborNurse4U · Jan 1, 2012

Here is an article about d-dimer during pregnancy: http://www.gptt.com.au/Exam%20preparation%20CK%20Khong/RACGP/Check/Imaging/ddimer.pdf

88nurse2010 · Jan 2, 2012

Thank you!

SentimentalGeek, ADN, RN · Jan 8, 2012

Forgive me for butting in, just thought this thread was interesting. I had HELLP syndrome during my second pregnancy and have read a lot about it since - and it seemed that I've read an elevated d-dimer test could be predictive of patients developing HELLP syndrome if they are at risk of or already have pre-eclampsia. Is this not the case?

RNLaborNurse4U · Jan 11, 2012

D-dimer alone is not a good diagnostic test for preeclampsia/PIH/HELLP. You need to look at the entire clinical picture, and in conjunction with the other labwork. D-dimer can be elevated in a normal pregnancy, due to the hypercoagulable state of pregnancy (which is normal). It can also be elevated in the case of any type of blood clot (DVT, PE). D-dimer can be elevated when the woman is on therapeutic/preventative low molecular weight heparin for DVT tx or prophylaxis.

I don't believe that the d-dimer test is predictive of HELLP syndrome in patients at increased risk for it.

Remember too, HELLP is:

Hemolysis (reduction in RBC, H/H levels)

Elevated Liver enzymes (ALT, AST)

Low Platelets

D-dimer can range greatly from woman to woman, and also varies during the gestation. There really is no clear cut range of "normal" levels for D-dimer, and it is not a specific enough test to predict if someone is heading towards HELLP.

SentimentalGeek, ADN, RN · Jan 11, 2012

Interesting! Thanks for the informative reply.

I found the article I was thinking of and it said the following, so I was confused.

"Early diagnosis is critical because the morbidity and mortality rates associated with the syndrome have been reported to be as high as 25 percent. Platelet count appears to be the most reliable indicator of the presence of HELLP syndrome. The D-dimer test may be a useful tool for the early identification of patients with preeclampsia who may develop severe HELLP syndrome. "

HELLP Syndrome: Recognition and Perinatal Management - September 1, 1999 - American Family Physician

So I'm assuming this means the d-dimer could be indicative of HELLP if the platelet count is already low?

RNLaborNurse4U · Jan 12, 2012

Yes, I would take that as what it means. Low platelets is usually your big light bulb to diagnose or start to think of HELLP (or worsening preeclampsia). I think I took your original question as more of using D-Dimer as a dx method for HELLP. Back to the original issue with D-dimer is the fact that it could normally be elevated in pregnancy. Could totally have nothing to do with preeclampsia or HELLP.