Feto-maternal Hemorrhage (FMH) - Summary

Dear Flow-ers,

Some weeks ago I've asked about the benefit to performing flow 
cytometry for Feto-maternal hemorrhage (FMH) estimation ante-natal and 
if so, what exclusive fetal markers are available for flow to be 
preformed ante-natal following FMH. 

I want to thank for your help and your replies. Bellow you can find 
the summary of the replies that I've received. What is clear is that 
the World leader in this assay is Bruce Davis. He has created the 
assay sold by Invitrogen, but there are another companies with another 
markers in the market and they are working well as well.

Summary:

"You can try this regent from Chemicon/Millipore, it's working very 
well in our hands,
http://www.millipore.com/catalogue/item/mab3435f-100t

--

We did some projects on this here as with a busy maternity hospital on 
site it is a big issue,
1) At the moment we do Kleihauer only as we are not adequately staffed 
to provide this service (which is a highly litigious area). There are 
so many variables.
2) The Kleihauer is quite reliable in the hands of an experienced 
user. Many of the requests for testing do not involve patients who are 
not Rh Neg and these are the ones we do - car accident, fall, bump 
etc.  If you look at the NEQAS results and compare them with the flow 
it is quite good and very inexpensive reagent wise.  So even if you 
use flow you would definitely need to have this technique available 
for these circumstances.
3) The flow is only as good as the antibody and I have recently seen a 
case of a weak D (there is variable expression of the D antigen)where 
the bleed would be detected by Kleihauer and not by flow.
4) We looked a kit (made in Holland) that had anti-fetal Hb antibody 
and anti-i combination which could distinguish adult from fetal cells. 
It was very nice and worked well but was very time consuming requiring 
permeabilization of the RBCs for the Anti-Fetal Hb. Not on for routine 
use and I don't think it’s on the market any more. 
5) If you use an anti Fetal-Hb on its own you have the complication 
that some haempoglobinopathies (and with immigrant population we have 
meny HbSs etc)Fetal Hb can be increased normally(and also during 
pregnancy). The kit could distinguish between each type of Fetal Hb.
6)You can see why we are slow to introduce a service as there are so 
many variables no matter how you go.

--

Determination of fetal HbF by flow cytometry is by far more superior 
method than old K-B test, so no conjunction is needed. First, it is 
more sensitive and number of false positive / false negative results 
goes down. Second, flow test not only distinguishes fetal red cells 
from adult red cells, it also allows you to identify a population of F-
cells (adult red cells carrying fetal form of hemoglobin). K-B test 
will count these cells as fetal and report positive answer. In reality 
this result is negative, and presence of F-cells (which points to 
sickle cell anemia, MDS and thousand other medical conditions) is no 
harm for fetus development.
I spent a lot of useless time, trying to convince my doctors to start 
this test for our hospital (the biggest Women's Center in US) and did 
not achieve much. The reason: doctors want it to be done on 24 / 7 
mode, which can be done in 24 hours functioning hematology lab, but 
cannot be done in Flow lab. I know quite a few people in US, who 
experience the same trouble. Some labs were able to manage flow-base 
test on Monday-Friday, 8 to 6, and K-B out of business hours. I could 
not get it through. Since I have tried it so hard, I still have a 
presentation with numbers and ideas, supporting transition from K-B to 
flow cytometry. If interested, get back to me and I will send it to 
you.

Meanwhile, if you decide to go with a flow test, you can either do one-
color flow, using AB from Caltag (Invitrogen now) and 3-level positive 
control, called Fetaltrol. They have distributors in Europe. Or you 
can find 2-color flow kit from company IQ (Netherlands), which 
supposely gives you more clear results on possible F-cells presence. 
For myself I like one-color flow just fine (combination of quality and 
price), but all this is personal."


Kind regards,

Alfonso



------------------------------
 Dr. Alfonso Blanco Fernández

 Flow Cytometry Core Facilities
 UCD - Conway Institute of Biomolecular & Biomedical Research
 University College Dublin
 Belfield, Dublin 4
 IRELAND

 T: 00353(0)1 716 6836/6947