Dear Gregory,

in Germany, we have to guarantee for a hemoglobin content of > 40 g/unit in our quality control units. Units not fulfilling this level must not be below a 5% deviation from this 40 g/unit.

Therefore, only the quality control units (1% of the production) are tested.

The question would be: How expensive is such a system? For a cost-effective use, the costs must be in the range of hemoglobin testing for 1% of the produced units.

Best,

Markus      

I agree with Markus... currently donors are just screened to meet a Hemoglobin thershold, and only a selected number of units are then QC'd. It would be costly to increase the numbers of units tested and labelled with the Hgb levels.  Maybe you could consider the Hct level by using the segments, but again, thinking of the labour involved with testing would there be an increase benefit of doing this?

in addition to previous answers: the range of Hb can by indeed large, depending on how standardazid your collection method is, but the weight of the unit reflect already reasonably good how much hemoglobin you have (as you add a standard amount of additive solution). Measurement of Hb adds some information to this, but limited.

Dear Markus, Tracy and Dirk

Thank you for your interesting comments and suggestions.

I think that a device that could evaluate the hemoglobin content in the PRBC unit, without violating its integrity, will provide the following benefits:

For Clinician

1. Achieving the desired increase in Hb level for specific recipient.

2. Minimizing of transfusion-related risk by keeping the amount of transfused units (one unit with high Hb content, instead of two).

For Blood Bank

1. Saving up to 30% of units compared to current routine (according to Arlslan et al Transfusion, 2004)

2. Introducing a novel quality control procedure, by a facile non-invasive methodology, for assessing the Hb content in PRBC units.

I would like to know your opinion.

Regards

Gregory

this can only be achieved if you know both: Hb concentration and volume of the unit

The change in practice now is only transfusing one unit and reassess for those hemo-dynamically stable patients. Not the standard two units because you should be assessing the patient based on clinical symptoms and lab values, not just lab values alone. 

http://annals.org/article.aspx?articleid=1206681

For Dirk,

Of course, we are talking about the instrument that is capable of non-invasive measuring the concentration of hemoglobin in the unit at a known weight. 

I fully agree with Tracy; so the benefit would be marginally for the clinician. Especially, since the increase in hemoglobin after transfusion relies on so many factors including the recipient (body weight, normovolemia, organ sizes (liver, spleen), blood loss, etc.).

Therefore, a non-invasive hb measurement, which is fully reliable (the current available systems are not really), cheap and not disturbing to the patient (e.g. a sort of a band-aid, which can be affixed to the skin and which is able to transmit the data wireless) would be a good solution. 

Thank you all for your comments.

In reply I would like to address the following points:

In regards to transfusion of more than one bag (Re: Tracy): To my knowledge this is not a universal practice, as in different situations more than one bag is transfused. For example, β-thalassemia major patients are routinely treated with along-life, frequent (every 2-4 weeks) with PRBC transfusion. In Israel, in about 40-50% of the treatments the patients are given two units.

In regards to patients’ conditions (Re: Marcus). I certainly agree with Marcus that the increase in hemoglobin concentration after transfusion depends on a lot factors, primarily his Hb level, and accordingly, effort is currently being made ( at least by one company) to develop a non-invasive device for monitoring the Hb level in the patients’ blood. However, this is one side of the equation, as the final outcome depends also the Hb level of the transfused PRBC unit.

Several studies reported a very large variability in the Hb content of PRBC units (30-85 g), while the blood banking routine assumes about the same content (around 50 g) in all units. Consequently, when the Hb is significantly lower, the transfusion would provide less Hb than required. This might lead to the lower increment of Hb than needed, and possibly to transfusion of an additional unit, which multiples the risk and increase the cost.

Therefore, a device for a facile assessment of the hemoglobin content in every PRBC units, applied to the intact bag (without taking a sample from the bag), would enable patient-specific transfusion (by selecting the bag that match the patient specific needs), thereby keeping the amount/number of transfused PRBC units at its minimum. This will reduce both the risk and cost of transfusion.

Storage lesion developed whenever the PRBC were stored in the refrigerator for a period of time no matter how high the HgB started with.  This would lower the Hgb level in PRBC.  Therefore, why not considering using fresher PRBC for specific needs patients?  For example, using less than 5 day of 10 day PRBC might be better than longer stored PRBC.  This woudl eliminate the need of measuring the HgB of the PRBC.  In our practice, we used less than 5 day old PRBC for neonates pedi-pump cases, and the beginning basket of PRBC for liver transplant patients.

Dear Frances,

Thank you for your comments.

The storage duration is only one factor in the properties of PRBC, and it is necessary to take to account a large variability in the PRBC properties, already on day of donation (Day 1).

Moreover, the use of shortly-stored units is practical for a very small population, while the majority of transfusion recipients are not “special cases”, and receive units stored for much longer time. Therefore, using shortly-stored PRBC would not necessarily solve the problem, and does not lessen the need to characterize the PRBC properties (specifically Hb content) for each unit.

Dear Gregory, if such device is successfully achieved, it will be of great help in the blood banking and in saving lives of patients who may be anaemic.

Dear Emmanuel, thank you for your response.