Platelets

Pathogen-reduced single donor platelets are transfusion-ready products that decrease the risk of transfusion-transmitted infections.

Platelets are collected in PAS to which the agent amotosalen is added. Upon exposure to UV light, the amotosalen crosslinks the nucleic acids present in bacteria, viruses and other pathogens thereby inactivating them. White cells (which can cause transfusion-associated graft vs host disease) are also inactivated, thus PR platelets do not require further irradiation prior to transfusion in patients at risk of transfusion-associated graft vs host disease. The pathogen reduction process is highly effective against CMV and mitigates the risk of transfusion transmitted CMV.

Bacterial contamination of platelet products is the most frequently cited cause of transfusion-transmitted infection as room temperature storage provides a favorable environment for bacterial growth. To reduce the risk of transfusion-transmitted infections, the Red Cross pathogen reduces most of its platelet products.

For more information about PR PLT, please refer to the following resources:

• Pathogen-Reduced Platelet Quick Reference Sheet.
• Pathogen-Reduced Platelet Implementation Guide.
   

Indications:

• Prevention of spontaneous bleeding due to thrombocytopenia or platelet dysfunction.
• Treatment of active bleeding.

Cold-Stored Platelets (CSP) are single donor platelets collected in platelet additive solution (PAS) and pathogen-reduced to decrease the risk of transfusion-transmitted infections.

CSP are collected with the same donor criteria and follow the same collection and manufacturing processes as conventional room temperature-stored (RT) platelets, however, at the end of the pathogen-reduction process, they are placed into 1-6 degrees C for the duration of their storage.

CSP shelf-life is 14 days.

Indications:

• CSP are intended for the treatment of active bleeding when conventional platelets are not available, or their use is not practical.

Large-volume delayed sampling (LVDS-36) platelets are held for ≥ 36 hours (as compared with the previous hold time of 24 hours) and larger-volume samples are taken to increase the likelihood of detecting bacteria in the platelet product.

Indications:

• Prevention of spontaneous bleeding due to thrombocytopenia or platelet dysfunction.
  
• Treatment of active bleeding.

The minimum yield specification of a standard apheresis platelet in the United States is 3.0 x 10¹¹ platelets per unit. However, the testing and manufacturing process can sometimes result in products that fall slightly below the minimum standard.

Low-yield platelets (LYP) can be used safely and effectively in massive transfusion protocols (MTPs) and other active bleeding scenarios. To ensure consistent product availability, the Red Cross may distribute low-yield LVDS and pathogen-reduced platelets containing 2.8 x 10¹¹ to 2.9 x 10¹¹ platelets.

For more information, refer to:

• Low-Yield Platelet Informational Video.
   

Indications:

• Prevention of spontaneous bleeding due to thrombocytopenia or platelet dysfunction.
• Treatment of active bleeding.

Platelet transfusions for pediatric and neonatal patients are dosed typically by patient weight. All platelets provided by the Red Cross can be aliquoted as per hospital procedures and guidelines for treatment of these small patients.

Indications:

• Prevention of spontaneous bleeding due to thrombocytopenia or platelet dysfunction.
• Treatment of active bleeding.

HLA-matched platelets are provided through the services of the Red Cross HLA laboratories. These facilities provide high quality histocompatibility and immunogenetics clinical laboratory testing in the interest of optimal patient care.

Human leukocyte antigens (HLA) present on the surface of transfused platelets can result in immune-mediated platelet refractoriness, a condition whereby the transfusion of platelets results in a lower-than-expected post-transfusion platelet count due to the presence of anti-HLA antibodies in the recipient.

Indications:

• Prevention of spontaneous bleeding due to thrombocytopenia or platelet dysfunction.
  
• Treatment of active bleeding.
• Patients that have thrombocytopenia and have demonstrated lower-than-expected corrected count increment (CCI) values consistent with immune-mediated platelet refractoriness on at least two occasions. Although antibodies against HLA Class I antigens are the most common cause of immune-mediated platelet refractoriness, antibodies against ABO antigens, or less commonly, platelet specific antigens (also referred to as human platelet antigens, or HPAs), may be involved. Patients with immune-mediated platelet refractoriness due to anti-HLA antibodies include multiparous women, recipients of multiple transfusions (particularly platelet or granulocyte transfusions), and recipients of organ transplants. Neonates may also experience transient thrombocytopenia and leukopenia due to passively acquired maternal anti-HLA antibodies.
  

Crossmatched platelets serve as a valuable resource for addressing the platelet transfusion challenges encountered by thrombocytopenic patients exhibiting immune-mediated refractoriness. This condition is identified when a patient demonstrates suboptimal platelet transfusion effectiveness with low corrected count increment (CCI) values on at least two occasions. CCI is an equation assessing the rise in platelet count by comparing a patient's pre-transfusion and post-transfusion platelet count when collected within 10 to 60 minutes after platelet transfusion. The utilization of crossmatched platelets is beneficial in situations where HLA Class I and platelet serology testing is pending or when HLA-matched platelets are unavailable or ineffective. This method can serve as an initial screening tool to identify potential platelet-specific antibodies targeting HLA Class I, HPA, and/or ABO antigens, as well as platelet autoantibodies, thereby guiding subsequent platelet serology testing.

Crossmatched platelets are readily accessible through multiple laboratories at the Red Cross and can be ordered by placing a Connect Service Order.

Indications:

• Prevention of spontaneous bleeding resulting from thrombocytopenia or platelet dysfunction in patients with immune-mediated platelet transfusion refractoriness.
• Treatment of active bleeding in patients experiencing immune-mediated platelet transfusion refractoriness.
• Patients with antibodies to HLA Class I, HPA, and/or platelet-specific ABO antigens.
• Patients awaiting results from HLA Class I antigen typing or antibody identification tests.
• Immune-mediated platelet transfusion refractoriness in patients who are unresponsive to HLA-matched platelets.

Platelet-specific antigen-negative units are needed for patients with certain conditions requiring platelet transfusions with platelets from HPA-1b/b donors. Anti-HPA-1a is the most commonly implicated antibody in the following conditions:

• Fetal and neonatal alloimmune thrombocytopenia (FNAIT), in which maternal-fetal platelet incompatibility leads to maternal antibodies to fetal platelets, leading to fetal/neonatal thrombocytopenia. The maternal antibodies are passively acquired against platelet-specific antigens, of which anti-HPA-1a is the most common.
  
• Post-transfusion purpura (PTP), in which thrombocytopenia occurs within two weeks of transfusion. Although rare, this transfusion-related complication is serious and may lead to life-threatening bleeding due to thrombocytopenia. Anti-HPA-1a is the most commonly implicated antibody for this condition.
• Alloimmunization to platelet-specific antigens.

HPA-1a negative platelets are readily accessible at the Red Cross and can be ordered by placing a Connect Service Order. Other HPA-negative units may be available upon request.

Indications:

• Prevention of spontaneous bleeding resulting from thrombocytopenia or platelet dysfunction in patients with immune-mediated platelet transfusion refractoriness due to HPA antibodies, FNAIT, or PTP.
  
• Treatment of active bleeding in patients experiencing immune-mediated platelet transfusion refractoriness. with immune-mediated platelet transfusion refractoriness due to HPA antibodies, FNAIT, or PTP.
  

Absolute IgA (aIgA) deficiency is defined by an IgA level of <0.05 mg/dL within serum or plasma. Patients with absolute IgA deficiency may develop anti-IgA antibodies. Although rare, patients with anti-IgA have been reported to experience anaphylactic reactions when receiving IgA-containing blood products and immunoglobulin infusions.

IgA-deficient platelets may be ordered through the American Rare Donor Program (ARDP) by placing a Connect Service Order for IgA-deficient blood products.