rravkin@aol.com

Can anyone give any references on the possibility of transfusing a unit of Single Donor Platelets that are reactive with EDTA?

Have you ever tried using this scenario in an in-lab continuing education exercise?

Thank you for the information Scott. It did compel some research where I found that the MCH actually measures the mass of hgb of the rbc in the middle (based on volume) of a group of counted rbc's while the MCHC is measuring the average hgb concentration of a group of packed rbc's, and therefore I stand corrected. I guess that I suspected a relationship between the MCH and MCHC because they both use the measured Hgb as numerators in their respective equations. Our DXH will flag an H&H check fail which will trigger a closer look at the H&H and the indices. If your MCV is low, MCH normal, and MCHC is normal to low, your H&H check fail is more than likely do to an rbc microcytosis. Here the cause of the H&H check fail is a higher HCT do to the microcytic rbc's. If you have an H&H check fail and the MCV and MCH are normal, but MCHC is >36 and your Hgb compares to the HCT as being higher you are probably looking lipemia; also you whole blood sample may appear a brighter than usual red color; but cold agglutin can cause these same results with darker red sample color. However, if your have an H&H check fail with low to normal MCV, low MCH, and normal to low MCHC you may be looking at an aged specimen. I have experienced these scenarios as I am sure you have, as well as many who attend this site but the last scenario that I described is not something I seen in the hospital setting very often but in a reference lab setting it is rare. Thank you again Scott and thank you PathLab Talk for the opportunity to conversate.

I just answered this question. My Score FAIL

Scott, I have always understood the MCHC as being the statistical Mean Hgb concentration of the rbc whose volume would be in the middle the lowest and highest volumes of a group of packed rbc's representing the HCT. The calculation for the MCHC is Hgb/HCTx 100= MCHC. Also, we practice to incubated for 30min or an hour depending on how strong the cold agglutinin is as represented by the elevated MCHC >36.0. If lipemia is found then we would do a saline replacement. And if there is a combination of lipemia and cold agglutinin we would replace with warm saline. Additionally, I understand the MCH as being the concentration of Hgb of the rbc that is present in the group of counted rbc's and whose volume is midway between the lowest and highest volumes of this group. The equation is Hgb/RBC's Counted x a given constant (where the given constant will act to manipulate the decimal place such that the result is given to one decimal place) = MCH. So with the MCHC one can see how rbc morphology will effect the Mean Hgb concentration determined by the MCH. In other words, the instrument that is used to count the red cells and determine the volume can not know the shape of these red cells. The hematocrit can give an indication of the shape of the red cells by the way they pack. A group of normal shaped red cells will pack differently as compared to acanthocytic red cells. This is why the result obtained for the MCH is often different then the result obtained for the MCHC. Another anomaly that can occur with an increased MCHC is an H&H check fail whereby the HGB is not 3x +/- 3 the HCT. This failure can occur with low MCV, rbc agglutination, lipemia, excessive icterus and/ or hemolysis, or the age of the specimen, to name a few. However the low MCV may often not be accompanied by an elevated MCHC.

Thank you TreeMoss but I was asking about Open Heart Surgical patients where their body temp would be lowered and as such some surgeons request a cold Ab screen be performed as part of the blood bank pre-surgical work up. If a blood warmer were used the cooler blood from a cooler surgical suite would course through a blood warmer and into a cooler then normal body, thus lowering the temp of the now transfused blood. Therefore, even if a blood warmer were used for this patient would a cold reacting antibody still be of some concern with respect to the minimal possibility of agglutination of these transfused rbc's?

So Treemoss, do you know if rbc agglutination, and the damage it can do to the microvasculature, is a concern with this surgical patient group if a cold antibody is demonstrating?

Let's not forget that we are dealing with a perishable product, packed rbc's, and not a non-perishable product like a book or a refrigerator.

Hey Exlimey, very well put.

David, I am not sure if there is a difference between transported and delivered, outside of potential semantics. If a package is delivered it was certainly transported. But I think that the FDA's thinking is based on the stored conditions during the transport; thus taking the transport part of the equation out of consideration. If you are familiar with the convenience retail chain, Wawa, one of their limitations on expansion is the safe storage of perishable products being delivered directly from their farm to surrounding stores. With advancement in storage capability they are able to expand; but notice that Wawa is only present on the east coast and not the west coast. This is because of the limitations on storage capability during transport. I believe that this may be the FDA's logic when addressing packed red blood cells.

Hi Scott and Exlimey, perhaps the idea of a hemolytic reaction is remote when considering cold agglutinins but if the patients body temp and OR temp are below normal body temp and room temp respectively, and, if the cold agglutinin is strong enough, either by way of concentration therein of bonding strength, does the cold agglutinin not have the capability of causing rbc agglutinins to form and remain stable long enough to cause damage to the microvasculature in the same manner as with Lupis Erythmatosis.?

Hi TreeMoss, I gather that you and your crew were not real inspired by this line of testing. When the practice was first explained to me it seemed like a good practice, the idea being that if the patient had a cold reacting antibody and needed transfusion during the procedure when their body temp was less than normal, perhaps the OR staff would be better prepared in treating any adversities. I guess that your new surgeons do not agree with this practice. But can I ask what kind of incubators were used in your blood bank to test at 10, 15, and 20C? The reason for my question is that I have only done cold incubations at BB Room Temp and 1-6C BB Refrig temp.

Hi Dansket, can you explain what you mean when you say "level of control"?

I was going to ask if distance traveled had anything to do with this distinction, transported or stored. But it is actually the container that is being transported and the blood is stored within this container. If the container is sealed such that the stored blood is not in any contact with the elements then the stored blood would be good until it's expiration provided the temp is maintained in this container. I think that the container's ability to maintain the appropriate temper for a given time and the time it takes to travel a given distance is probably where the question of transport and storage originates. But the temperature maintenance is a container issue and not the units of blood "stored within." If a pregnant woman travels a given distance can we think that the fetus she is carrying is transported or stored?

Hi Malcom, not withstanding the reference given, if there is indeed any contradiction, but I had a co-worker who practiced Blood Bank at a hospital where part of their type an screen practice was a 4C incubation for all open heart pre surgical patients. The idea being that the docs wanted to be aware of any cold agglutinins because during the surgery, and as a consequence of the proceedings, the patient's body temp would drop. To what degree, and how it compares to the referenced recommendation you site I do not know. I hope that retirement is treating you well and best wishes, Ronald.

Hi Dcamp67, I wonder if the question of QC for body fluid diffs and not whole blood manual diffs, arise because WBC's are not nearly as common to body fluids as compared to whole blood and as such perhaps a broader empirical understanding of variables of the resolution of WBC's in the matrix of whole blood is by far better noted and therefore removes the consideration for the practice of QC for manual whole blood diffs as compared to body fluid diffs. In other words the variables of WBC resolution in the matrix of body fluids may not be as well noted or understood or as practiced as compared to whole blood. I hope this helps some even though, for me, it just raises more questions.

Hi kholshoe, I would agree that the slide review criteria is set primarily by the medical director/ pathologist and as each may help to treat varying patient demographics and each pathologist has their own manner of practice, the criteria for the slide review would, indeed, be somewhat subjective. I have practiced in a number of hematology labs with each having their own criteria for slide review based on the practice of the pathologist signing off on the procedure. The establishment of the criteria seems to be mostly a top down decision with some influence by the supervisors who are closer to the actual work flow. In other words, the work flow of the lab, and technical staff practicing, may have some influence on this decision as well. I hope this helps.

Thank you for the info kimannez. I was not sure if the strong cold agglutinin would alter the distribution of rbc's prior to the lysing step significantly enough as compared to the diluted aliquot specimen. But I can see where a "harsh lyse" would be more useful. Can I ask, what instrument was in use for this testing?

Hi Kimmannez, I was curious to know what your acceptable range is between the neat hgb result and the diluted hgb result. Given that the strong cold agglutinin would significantly alter the rbc distribution of the neat specimen as compared to the diluted specimen my guess is that your range is broad. How was this range established and do you know of any references? Thanks for any info.

Scott, do you know the reason why the K result is considered negligible in the anion gap calculation? Is it because the K result is usually a much smaller number in comparison? And if this is the case then when the anion gap is at the border of the range, would the K result not make a difference there, at least numerically, but with questionable clinical relevance?

Thank you Scott. Multiple Myeloma is what I was thinking of.

If these cells are Lymphoma cells, and if I am not mistaken, would a follow-up Urine Electrophoreses be in order to detect Bence/Jones proteins?

Hi kblewett, Happy New Year. While I am no expert I would say, from a practical perspective, that I can not see how throwing away 90% of a perishable product, of the larger volume size, would be less expensive then buying less of the smaller volume size of the same product at higher cost initially but would allow for use of greater volume of the bottle, once opened, and sustain a longer shelf life, with the exception of unexpected storage environmental mishap, enabling you to absorb the higher cost. In other words, buy less quantity of the smaller volume size at an initial higher cost, but be able to use near 100% of the volume and because it is the smaller size you would be able to store it, unopened, for a longer period. These to benefits may help absorb some, or all, of the higher cost. I hope this helps some.

I did the same except the other department for me was Hematology. I realized after taking the BB ASCP and passing it the first time out that what helped me the most was my practical experience and not so much book study. As far as concern as to whether I should take the exam or not, I was concerned with any impact on my current position at the time if I did not pass this exam; but I am happy to say that those concerns were not warranted at all. So you should take this exam and any other exam that you are qualified to take.