H&H check time after RBC transfusion

[SMILLER]

In general, what is a good amount of time to wait to check a hemoglobin after a RBC transfusion?  I realize that the term "general" may be a bit too broad here considering all of the different conditions a patient getting transfusions may be in. 

What we are looking at is newer policy here at our hospital requiring a H&H for most RBC post-transfusion patients before an order is processed for any further transfusions.  We are anticipating questions on this.

If anyone has a definitive reference regarding a study on this or whatnot that would be nice to have also. 

Thanks, Scott

[AMcCord]

Old school thought was that you had to wait for 24 hours. I think that one to two hours is common practice.

I also remembered reading something in a CAP publication that discussed this and actually managed to find that in one of the threads here. There are references associated. Quoted below....................

Q. How long should you wait after a unit of blood has been transfused before drawing a complete blood count, or doing other lab work, to ensure accurate test results?

A. Optimum timing of post-transfusion phlebotomy is critical for ensuring meaningful laboratory testing results, and medical judgment is required in making this determination. Several factors must be considered, including the type and amount of blood product given, purpose of the test (that is, the question it is intended to answer), and clinical setting.

In general, it is best to perform phlebotomy when the patient’s circulatory system is in homeostasis. A patient who is bleeding or undergoing blood product transfusion, or both, is not in a steady state. Whenever possible, samples for laboratory testing should be postponed until bleeding has stopped and transfusion is complete. One obvious exception to this rule, however, would be the setting of massive transfusion, during which monitoring certain laboratory values, such as cell counts and coagulation parameters, is essential to guide ongoing therapy. Variables such as patient blood volume, cardiac output, renal function, and volume of blood products transfused affect how quickly homeostasis is achieved following transfusion.

For the evaluation of post-transfusion increments in hemoglobin, hematocrit, and platelet counts, a practical approach is to draw blood samples within 10 to 60 minutes after completing transfusion, as this time interval is aimed at measuring peak recovery.1 Results determined from blood samples drawn later than 60 minutes post-transfusion are increasingly affected by confounding conditions, such as splenic sequestration, sepsis, and consumption.^1,2 If the intent is to determine the extent of such confounding processes on red cell and platelet counts, one should combine a 10-minute post-transfusion sample with sequential samples drawn at one hour and 24 hours post-transfusion.

Alterations in chemistry test results following transfusion are not usually a concern in the low-volume transfusion setting. However, assay results may be affected for varying periods following transfusion of large amounts of blood products, as seen in massive transfusion, red cell, or plasma exchange—particularly if the recipient has impaired hepatic or renal function. Banked storage of red cells results in elevated plasma levels of hemoglobin, potassium, LDH, and iron in the blood unit that may, particularly in the metabolically impaired patient, be reflected in the post-transfusion laboratory values. In addition, citrate anticoagulant present in blood products may result in transient hypocalcemia in the recipient.³ Therefore, following large-volume transfusions or exchanges, waiting 12 to 24 hours before drawing samples for chemistry assays will provide results that are more reflective of the patient’s underlying metabolic state.

References

1. Choo Y. The HLA system in transfusion medicine. In: McCullough J, ed. Transfusion Medicine. New York, NY: *McGraw–Hill Book Co;1998:401.
2. Legler TJ, Fischer I, Dittman J, et al. Frequency and causes of refractoriness in multiply transfused patients. Ann Hematol. 1997;74:185–189.
3. Brecher ME, ed. Technical Manual. 15th ed. Bethesda, Md.:AABB;2005;649–650.

 

Rita A. Reik, MD

Pathology Consultants of South Broward

Medical Director/Transfusion Medicine Services

Memorial Healthcare System

Hollywood, Fla

 

Edited November 30, 2012 by Justina
Added CAP website find

Justina

Posted December 7, 2012

Articles:

Elizalde JI, et al.Early changes in hemoglobin and hematocrit levels after packed red cell transfusion in patients with acute anemia. Transfusion. 1997 Jun;37(6):573-6

Wiesen AR, et al. Equilibration of Hemoglobin Concentration after Transfusion in Medical Inpatients Not Actively Bleeding. Ann Intern Med. 1994;121:278-280

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Edited October 17, 2017 by AMcCord