The platelet count in EDTA-anticoagulated blood from patients with thrombocytopenia may be underestimated when measured in routine laboratories.
Spuriously low platelet counts (PCs) can be observed in normal blood samples anticoagulated with ethylenediamine tetra-acetic acid (EDTA)and, much less frequently, with citrate-tris-pyridossalphosphate (CPT),due to time-dependent in vitro platelet agglutination. Accuracy in PC determination is essential as PC is one of the parameters that usually guides treatment for thrombocytopenic patients. PCs of 93 thrombocy to penic patients were measured in EDTA- or CPT-anticoagulated blood samples immediately after sampling (t0) and 90 min (t90) after storage at room temperature. The presence of platelet agglutinates in blood samples was determined by examining blood smears using optical microscopy.PCs decreased at t90 with both anticoagulants. Platelet agglutinates were present at t90 in 27% of EDTA-samples vs. 2% of CPT-samples with decreased PCs (P < 0.001). Based on PCs in EDTA-samples, 15 patients (16%) shifted from a lower bleeding risk at t0 to a higher bleeding risk category at t90 (P 5 0.019), compared to 5 (5%) patients, based on PCs in CPT-samples. Therefore, time-dependent in vitro platelet agglutination in EDTA-blood samples may cause underestimation of PCs in thrombocytopenic patients, possibly leading to improper management.
Medicina III, Ospedale San Paolo, Dipartimento di Medicina, Chirurgia e Odontoiatria, Università degli Studi di Milano, Milan, Italy.
Gian Marco
GM
Podda
Mariateresa
M
Pugliano
Eti Alessandra
EA
Femia
Anna Maria
AM
Mezzasoma
Paolo
P
Gresele
Giovanni
G
Carpani
Marco
M
Cattaneo
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000371:Agglutination / Q000187:drug effects; D000925:Anticoagulants / Q000494:pharmacology*; D001792:Blood Platelets / Q000187:drug effects*; D002614:Chelating Agents / Q000494:pharmacology*; D002951:Citrates / Q000494:pharmacology; D003951:Diagnostic Errors; D004338:Drug Combinations; D004492:Edetic Acid / Q000494:pharmacology*; D005260:Female; D006470:Hemorrhage / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D011732:Pyridoxal Phosphate / Q000494:pharmacology; D012306:Risk; D013921:Thrombocytopenia / Q000097:blood / Q000175:diagnosis* / Q000503:physiopathology; D013997:Time Factors; D014325:Tromethamine / Q000494:pharmacology; D055815:Young Adult
D000925:Anticoagulants; D002614:Chelating Agents; D002951:Citrates; D004338:Drug Combinations; C064185:pyridoxal phosphate, trisodium citrate, tromethamine drug combination; D014325:Tromethamine; D011732:Pyridoxal Phosphate; D004492:Edetic Acid