platelet specific antigen negative platelets (HPA-1a negative platelets) (Blood Component)

Brand and Other Names:
  • Print

Dosing & Uses

AdultPediatric

Alloimmune Thrombocytopenia

There is no difference in dosing platelet specific antigen negative platelets compared to standard platelet dosing. Please see platelet monograph for dosing information.

Other Indications & Uses

Platelet specific antigen negative units are indicated for neonates with neonatal alloimmune thrombocytopenia (NAIT) due to passively acquired antibodies against platelet specific antigens.

Platelet specific antigen negative units are also indicated for patients with alloimmune refractory thrombocytopenia due to antibodies against platelet specific antigens.

Additional studies, including platelet serology assays may be useful. Alternatively, platelet crossmatching may be performed to screen for platelets that might have improved post transfusion increments. The most common platelet specific antibody implicated in alloimmune thrombocytopenia is HPA-1a; however there are other high frequency antigens that antigen negative recipients can form antibodies against leading to alloimmune thrombocytopenia.

Providing platelets for alloimmune thrombocytopenia vary by institution and your blood bank physician should be consulted for assistance.

Alloimmune Thrombocytopenia

There is no difference in dosing platelet specific antigen negative platelets compared to standard platelet dosing. Please see platelet monograph for dosing information.

Next:

Adverse Effects

Frequency Not Defined

Hemolytic Transfusion Reactions

Febrile Non-Hemolytic Reactions

Allergic Reactions ranging from urticaria to anaphylaxis

Septic Reactions

Transfusion Related Acute Lung Injury (TRALI)

Circulatory Overload

Transfusion Associated Graft Versus Host Disease

Post-transfusion Purpura

Previous
Next:

Warnings

Contraindications

Platelet antigen specific negative units are not indicated in patients that have not demonstrated alloimmune thrombocytopenia due to a specific platelet antibody.

Cautions

Ordering platelet specific antigen negative units may require a marked time delay of days to weeks or may not even be possible. Consult your blood bank physician and/or hematologist for recommendations in managing bleeding patients with alloimmune thrombocytopenia.

Since NAIT is a transient problem due to passively acquired antibodies, other strategies such as obtaining washed (and irradiated) maternal platelets or increasing the dosage of untested platelets may be attempted. Consultation with your blood bank physician and/or hematologist is advised.

Please see platelet monograph for complete safety/caution information.

Previous
Next:

Pregnancy & Lactation

Please see platelet monograph for pregnancy/lactation information.

Pregnancy Categories

A:Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B:May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C:Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X:Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA:Information not available.

more...
Previous
Next:

Pharmacology

Platelet specific antibodies against these high frequency antigens have been implicated in NAIT.

Antigen: Phenotypic Frequency

HPA-1a : 98%

HPA-2a: 99%

HPA-3a: 85%

HPA-4a: 99.9%

HPA-5a: 99%

HPA-15a: 80%

NAIT may be caused by antibodies against other lower frequency platelet specific antigens, but these usually can be adequately treated with untested platelets since these antigens are not present on most donors.

Mechanism of Action

Please see platelet monograph for mechanism of action.

Previous
Next:

Images

Previous
Next: