According to one e-network member, his/her institution avoids the use of sickle trait blood for exchange transfusions in newborns because of a report of red cell sickling in this setting. Because the transfusion of a unit of whole blood in a neonate is essentially an exchange transfusion, this institution avoids the use of sickle trait blood for whole unit transfusions (e.g., surgery) in neonates. It has also been that institution's policy to avoid the use of sickle trait blood for patients with sickle cell anemia. This is because the clinical hematologists at that institution are concerned that sickle trait blood could theoretically participate in the sickling process at the small vessel level.  While the theoretical concern is justified, this e-network member was not aware of literature that documents that this occurs clinically.  The avoidance of the use of sickle trait blood can complicate protocols involving the provision of phenotypically similar blood for these patients.

A second e-Network member commented that if a sickle trait blood donor meets the hemoglobin and all other donor requirements, a blood donation is allowed. However, this member's institution makes sure that sickle trait red blood cells are NOT transfused to neonates. Furthermore, that institution does not freeze sickle trait red blood cells, unless the red blood cells possess a VERY RARE blood type.

A third member commented that at his institution, no testing is done to detect for sickle cell trait red blood cells, since cell trait blood is appropriate for transfusion.

ADDENDUM, Nov. 12, 1999

Because the above opinions suggested that some, but not all institutions worry about using sickle cell trait red blood cells, I requested a survey of member institutions to determine which institutions do or do not test for and restrict the use of sickle cell trait red blood cells, for selected patients.

A few institutions that did not originally respond to the initial question did so for this survey, as did one CBBS individual member. Here are the results of that additional input.

The CBBS individual member pointed out that Section I7.100 of AABB's Standards states: "In the case of massive or exchange transfusions of infants under 4 months of age, only blood known to lack hemoglobin S should be transfused." This is a hard-and-fast rule that would not be violated, unless the circumstance were absolutely extraordinary. Likewise, if it were known that a particular RBC unit came from a sickle trait positive donor, the unit generally would not be used for the transfusion of a patient with sickle cell disease, since such a unit might be expected to yield sub optimal clinical results. However, this it is not a hard and fast requirement to sickle trait-screen RBCs before transfusing them into sickle cell disease patients (although some hospitals do this). An RBC known to be sickle trait positive may be transfused into any other patient; however, it is prudent to limit the use of such units to adult patients, if at all possible. The Take-Home Message according to this member is that: "Our blood center has informed our hospitals that they should sickle trait-screen all RBC units that are to be used for the massive or exchange transfusion of infants < 4 months old". The member stated that they do not promote such a screening requirement for other patients; however, some of the hospitals in this member's area extend their sickle trait screening programs to include RBCs intended for sickle cell disease patients.

The survey results are as follows:

A. Prior to preparing a donor RBC unit for any kind of neonatal transfusion (including replacement or exchange) the unit IS tested for sickle trait:

RESPONSES:   yes = 2;  no = 1

B. Prior to preparing a donor RBC unit for a neonatal 'replacement/exchange' transfusion the unit IS tested for sickle trait: 

RESPONSES:   yes = 1;  no = 2

Please submit comments to the e-Network Forum.

Ira A. Shulman, MD
CBBS e-Network Forum Editor & Moderator