Specimen for Fetal Screen

[Marilyn Plett]

An H&H is a hemoglobin and hematocrit. This is one abbreviation that I would have expected to be common to both sides of the Atlantic. Wasn't it George Bernard Shaw who said: "England and America are two countries separated by a common language."

[Malcolm Needs ☆]

An H&H is a hemoglobin and hematocrit. This is one abbreviation that I would have expected to be common to both sides of the Atlantic. Wasn't it George Bernard Shaw who said: "England and America are two countries separated by a common language."

Thanks Marilyn.

I think GBS was right! We call it a FBC (full blood count).

:)

[Malcolm Needs ☆]

Thank you Malcolm. But why is it that we have this convention in practice that a blood specimen for H&H should be drawn 2hrs post transfusion?

From what I understand there is typically a two day time frame for which the injection of RhoGam is to be administered post delivery. This may account for the testing lag time at some facilities and may account for floor staff practice in aquiring the specimen as well.

I'm not absolutely sure of my facts here, as I am just back from a wedding, and perhaps, cerebrally, not quite at my best (the champagne flowed), so I'll check properly tomorrow, but I think that this is not so much to do with the red cells being sequestered by the spleen, than the fluid being returned to the peripheral blood circulation from the interstitial fluid, and the deeper blood circulation, because, if a person requires a transfusion (or, at least, if a person requires a transfusion for massive blood loss), the peripheral blood circulation, largely, shuts down.

As I say though, I am writing this through something of a haze, and will check my facts tomorrow.

:tongue::tongue::redface::tongue::tongue:

[Steven Jeff]

Thanks Marilyn.

I think GBS was right! We call it a FBC (full blood count).

:)

Malcolm, our friends across the pond call a full blood count - CBC (coulter blood count - I think) do coulter still exist?

Steve

:rolleyes:

[SusanM]

not being a hematologist so i don't really know, but i always assumed CBC was "complete blood count"

[Steven Jeff]

Susan, You could well be right, I had not considered that possibility.

Steve

:)

[swede]

Susan is correct, it is a complete blood count

[jcdayaz]

Thank you Malcolm. But why is it that we have this convention in practice that a blood specimen for H&H should be drawn 2hrs post transfusion?

The theory on this practice is that you are checking the rbc transfusion benefit/deficit(hopefully not the latter) impact on the patient. To effectively do this, you have to allow time for the transfused rbc's to mix and circulate with the patient's own blood. I will say we prefer a one hour post-tranfusion specimen. I have no references for the one hour guideline. I just know that's what we suggest.

[jcdayaz]

:cries:They have you trained to do their "fetching"!!

My thoughts exactly!!!:mad::mad: That is ridiculous! Why is our time less valuable than theirs?

I hate to think of the possiblility of a BB tech doing a "fetching" and an Emergency release situation presents itself.

I have been guilty of telling nurses who ask for blood products to be delivered that we are not a Pizza Delivery Service. :D:D:D:D:D I'm surprised I haven't gotten in trouble for that one yet.

[John C. Staley]

My thoughts exactly!!!:mad::mad: That is ridiculous! Why is our time less valuable than theirs?

I hate to think of the possiblility of a BB tech doing a "fetching" and an Emergency release situation presents itself.

I have been guilty of telling nurses who ask for blood products to be delivered that we are not a Pizza Delivery Service. :D:D:D:D:D I'm surprised I haven't gotten in trouble for that one yet.

This is why we fell in love with pneumatic tube systems. No more nurses requesting delivery of blood products. (Usually told them; "If I'm delivering I'm not crossmatching!!"), No more nurses. nurses aids standing tapping thier toes while we are getting the blood issued for them. No more visits at all from nurses. How much better could it be!!!!

:boogie::boogie:

[Malcolm Needs ☆]

I'm not absolutely sure of my facts here, as I am just back from a wedding, and perhaps, cerebrally, not quite at my best (the champagne flowed), so I'll check properly tomorrow, but I think that this is not so much to do with the red cells being sequestered by the spleen, than the fluid being returned to the peripheral blood circulation from the interstitial fluid, and the deeper blood circulation, because, if a person requires a transfusion (or, at least, if a person requires a transfusion for massive blood loss), the peripheral blood circulation, largely, shuts down.

As I say though, I am writing this through something of a haze, and will check my facts tomorrow.

:tongue::tongue::redface::tongue::tongue:

Right, I've checked some old notes, and I was more or less right, if the patient has had colloids or crystalloids prior to transfusion.

Apparently, it depends upon the molecular weight of the colloid or crystalloid as to whether they stay in the patient's circulation (and for how long), whether they go out into the interstitial fluid, or how quickly they are excreted. The molecular weight influences the "suckability" (an anaesthetists word, not mine) of the fluid, as to whether fluid comes into, or goes out of the circulation.

As a result, you should wait a little longer to let the whole thing settle down, so that you get an accurate Hb and Hct.

Though I say it myself and shouldn't, not bad for someone who was awash with ethanol the other night!!!!!!!!!!

:D:D:D

[TimOz]

Malcolm,

I thought there may be some potential fluid sequestering effect from patients with an enlarged liver. Excellent of you to personally run an experiment?

:clap:

[adiescast]

I'm not sure he thought to draw comparative samples while he was running his personal experiment...

[rravkin@aol.com]

Malcolm,

H&H= hemoglogin/hematicrit.

[jcdayaz]

Malcolm,

I'm performing my own "personal experiment" tonight!!After a phone call at work today from the principal at my youngest son's school...well, I decided why not!

[jcdayaz]

Malcolm,

I thought there may be some potential fluid sequestering effect from patients with an enlarged liver. Excellent of you to personally run an experiment?

:clap:

:D:D:D:DMalcolm and I should do some sort of comparitive study on our liver sizes!!!:D:D:D:D

Sorry Malcolm, I think I would win!!!

[Malcolm Needs ☆]

:D:D:D:DMalcolm and I should do some sort of comparitive study on our liver sizes!!!:D:D:D:D

Sorry Malcolm, I think I would win!!!

Hmmm, not sure about that; I probably have many years more experience. I was weaned on the stuff!!

[jcdayaz]

This is why we fell in love with pneumatic tube systems. No more nurses requesting delivery of blood products. (Usually told them; "If I'm delivering I'm not crossmatching!!"), No more nurses. nurses aids standing tapping thier toes while we are getting the blood issued for them. No more visits at all from nurses. How much better could it be!!!!

:boogie::boogie:

Hey! No more nurse visits.....hmm...very tempting!! Unfortunately at my current hospital the pneumatic tube system only supplies the ER and OPA (Out Patient Admitting). So it wouldn't work where I am now.

I did work several years at a Children's Hospital where we used the tube system to transport blood. When I first started there I remember being horrified at the thought of putting a unit of blood in the tube system and losing control of it. (Gee, think I have CONTROL issues?) I did, however, eventually come around and realize the benefits. If my memory serves me correctly, we only lost several units into what we unaffectionately referred to as "tube la-la land".

In most circumstances at my current hospital what we call POCT's (Point of Care Technicians) come to the Blood Bank to pick up blood products. They are so overworked, understaffed, abused, etc etc. that most of them really appreciate the opportunity to sit down for a few minutes while we get the blood ready to issue. No toe-tapping from them! Matter of fact, I have been asked countless times to take MORE time so they could catch their breath.

[profbaud]

The only requirement for a fetal screen specimen is that it be drawn POST partum. The timing doesn't matter so long as it's done within 72 hrs for administering RHIG.

[conwaysbb]

Having had to revise our Fetal Screen Testing SOP recently I had to go to our product insert for the Fetal Bleed Screening test that we use. I was also surprised from having supervised previous facilities how different the SOP of my current establishment, was from my previous establishments, even though we were using the same reagent, Immucor's Fetal Bleed Screening Test.

Specifically the product insert has in the Intended Use section, that the test is intended for use in the detection of D-Positive red blood cells in D Negative mothers after delivery. Therefore for the use of this specific test, the use of this test is only indicated in post partum testing and not in cases of traumatic injury to the mother or fetus, amniocentesis or other invasive prenatal testing that may cause feto-maternal hemorrhage.. There is also the issue of determining the blood type of the newborn, as babies with the Weak D may not detect a feto-maternal hemorrhage exceeding 30 ml of whole blood. ( Other than for donors, this is one of the only times the Weak D test is required to be performed)

As many of our requests from the ER for the fetal Screen test is to determine whether the mother has had a larger than normal feto-maternal bleed, and not to give Rhogam, the appropriate test to order would be the Kleinhauer-Betke test. Of course if the fetal screen test is used in this instance, you will get a false negative result for a feto-maternal hemmorhage if the fetus is Rh Negative. That is how our Policy and Procedure is set up now and it is only performed other than for paost partum patients only at the specific request of the patient's MD.

Ironically enough, we had a big to do about this issue from one of our OB/GYNs when a fetal screen that was performed was negative and the Kleinhauer-Betke test that was performed was Positive. The OB/GYN insisted that the laboratory had made a mistake and that the Blood Bank's result was in error. Had to do a presentation to the OB/GYNs on these two tests and why they could have different results (even the Kleinhauer Betke could be incorrect depending on the mother's Hemoglobin type).

In regards to the 48 hour recommendation for giving RH Immune Globulin, we normally use 72 hours as a rule, but if not given within 72 hours, it doesn't hurt to give it later than 72 hours. In fact the 72 hours is an arbitrary time frame and is associated with the original research of RH Immune Globulin on Rh Negative male prisoners. (that is another story).

Finally on this issue, and specifically for Immucor's product, in the Specific Performance Characteristics section of the product insert it states "The performance of this product is dependent on adhering to the recommended methods found in the insert". Legally that means if you use the product for anything other than post partum specimens, and you get a false positive or false negative result, you are on your own and must leave Immucor blameless.

What other manufacturer's Fetal Bleed Screening test are there, other than Immucor's?

Edited February 23, 2010 by conwaysbb

[amym1586]

Sorry to bring a post back from the dead...

 

 

Our procedure states "....if an ER patient that has come in with symptoms of a miscarriage, the fetal screen will be done on the same sample as the Type and Screen."   

The procedure for the FMH screen states a suspension from a well-mixed maternal sample is made.

Would remixing a spun down Type and Screen still count as a well-mixed sample?

[goodchild]

Make sure you read the entire package insert.

Ours states that the specimen should be from a known Rh-negative mother, collected as soon as possible after the first hour post-delivery of all products of conception, and the baby is Rh-positive.

[amym1586]

ah, touché.

So what do you do in the case of a greater >13 week miscarriage? With an undetermined/ unknown Rh of the baby?

 

 

[amym1586]

ah, touché.

So what do you do in the case of a greater >13 week miscarriage? With an undetermined/ unknown Rh of the baby?

 

 

[AMcCord]

If miscarriage > than 13 weeks and/or unknown Rh type of the baby, we perform the FMH screen. If we are doing the FMH screen, it needs to be drawn after all 'products of conception' have been delivered/removed. So for the >13 weeks or unknown age, we do the FMH screen on a specimen drawn after the D&C, if they do it, or after the miscarriage if it's 'complete'. The patients that need the FMH screen done are usually the ones that we see post-op rather than through the ER.