the importance of pseudo thrombocytopenia due to platelet cold agglutination before surgery, what should we do? a case report

Platelet cold agglutination (pca) is a rare in-vitro phenomenon caused by immunoglobulin m (igm) autoantibodies, which results in ethylenediaminetetraacetic acid (edta) independent pseudo thrombocytopenia (ptcp). its diagnosis is made based on the peripheral blood smear (pbs) examination and pre-test warming blood sample. here, a case of ptcp secondary to pca is presented. he was first admitted for pre-surgical tests but his platelet count was low. his blood was taken with edta and sodium citrate anticoagulant to rule pre-analytical error out. then his sample warmed up and the test was run again with mindray bc-6000 automated cell counter. moreover, the rheumatologic tests were done for him. his platelet count was 23×10^9/l at first, and pbs showed many platelet aggregates. the low platelet count was not correct with sodium citrate or re-sampling with edta so platelet satellitism and improper sampling were ruled out. by warming the sample up to 37⸰c, the platelet count rose to 216×10^9 / l. the rheumatologic tests were negative except for hla-b27 which was positive. finally, he was diagnosed with pca which is due to a cold antibody (clinically insignificant). this diagnosis is important for the prevention of recurrent tests, unnecessary platelet transfusion, and other problems. here these conditions will be discussed.