Reverse grouping is not required in infancts less than 6 months of age.But, i found many ABO discrepancies case in infacts between 6 months and 12 months of age.

How do i handle this situations?

Forrest

Reverse grouping is not required in infancts less than 6 months of age.But, i found many ABO discrepancies case in infacts between 6 months and 12 months of age.

How do i handle this situations?

Forrest

I wouldn't worry about it too much. There are two things that commonly cause discrpancies in this age group.

Firstly, from the reverse grouping point-of-view, although the books all say that babies will make anti-A and/or anti-B by six months, it is the usual "bell-shaped" curve situation of normal distribution, in that you will always get some babies that produce these antibodies early (some even by birth - proved by the fact that either the mother does not possess the antibody herself, or that the antibody is IgM, which, of course, will not pass through the placenta), and some who make them much later than 6 months.

Secondly, from the forward group point-of-view, the ABO antigens are not direct gene products. Rather, the direct gene products are transferase enzymes, and these enzymes do not necessarily reach their full kinetic maximum by 6 months (they haven't read the text books either!), and so, occasionally, you will get surprisingly weak reactions with anti-A/and or anti-B grouping reagents for some considerable time after birth.

I hope that helps a bit.

:comfort::comfort:

Thanks!

My further question about it is that, in this situation, can i issue the grouping result only based on forward grouping result? any supporting file for doing this?

I can't remember have got weak reaction in this age span of child. Maybe the reagent and the method differ.

I wouldn't worry about it too much. There are two things that commonly cause discrpancies in this age group.

Firstly, from the reverse grouping point-of-view, although the books all say that babies will make anti-A and/or anti-B by six months, it is the usual "bell-shaped" curve situation of normal distribution, in that you will always get some babies that produce these antibodies early (some even by birth - proved by the fact that either the mother does not possess the antibody herself, or that the antibody is IgM, which, of course, will not pass through the placenta), and some who make them much later than 6 months.

Secondly, from the forward group point-of-view, the ABO antigens are not direct gene products. Rather, the direct gene products are transferase enzymes, and these enzymes do not necessarily reach their full kinetic maximum by 6 months (they haven't read the text books either!), and so, occasionally, you will get surprisingly weak reactions with anti-A/and or anti-B grouping reagents for some considerable time after birth.

I hope that helps a bit.

:comfort::comfort:

Malcolm,

How do pre-mature (Primies?) infants fit into the information you provide? If they are a part of the population that you speak of here, how do they effect the curve? As I have had some freinds who were premature at birth they seem to have a more hyperactive immune system.

No Ronald, the bell-shaped curve of which I speak are for babies who have had a normal gestation period.

I must admit, I have no idea why premature babies should have hyperactive immune systems. Over to a proper immunologist?????????!!!!!!!!!!!!!!!!!!!!

Perhaps the hyperactive immune system develops later as part of the premature syndrome? I have not observed any hyperactive immune activity in the premies who are still < 1 year old at our institution. It may also be important to remember that if you have been transfusing them all along, they could have some donor antibodies circulating which might confound the issue.

And transfused babies often will have received O blood regardless of their type so that could "weaken" a forward type (mixed field really). This is something for the smaller hospital that has to "top off" a baby that finally came home after spending weeks in a NICU in a bigger city getting O neg blood.

We had a baby once that was typed as A pos on cord blood at birth; she was a preemie that got lots of O transfusions. The lab at the big hospital thought maybe the cord typing sample ID was wrong. When she came home to our smaller hospital we typed her as O and had to transfuse her regularly for a few months. Turned out that besides being early she got Parvovirus B19 which suppressed her marrow until they figured it out and started treating her (I think with antivirals). Very slowly she started to show some A cells and then she quit needing to be transfused so we don't know what happened after that.