An anti-EDTA antibody-like substance (EDTA Ab.), which interfered with ABO blood type grouping, was detected in a 72-year-old male suffering from liver cell carcinoma. So far, only a few cases of EDTA Ab. have been reported in the literature.
The panagglutination activity caused by this EDTA Ab. could be detected only in the presence of EDTA at the room temperature, but not in the presence of other mono- or polycarboxylic acids. The activity disappeared at 37°C. Pretreatment of the patient's serum with 2-mercaptoethanol extinguished the activity, suggesting that the activity was attributable to a IgM type antibody. Although the patient showed pancytopenia, that seemed to be due to hypersplenism: Coombs' test was negative, and signs of hemolytic anemia or those of pseudothrombocytopenia could not be found. On the other hand, all of serum samples obtained from six patients with EDTA-dependent pseudothrombocytopenia did not cause the panagglutination. Thus, the correlation between the EDTA-dependent panagglutination and pseudothrombocytopenia could not be found. The agglutination titer of this patient had decreased in three months. Although, we could not definitely identify the intake route of EDTA in our patient, EDTA is now permitted to be added to many kinds of foods and to contrast media for clinical use. Consequently, we should have increasing opportunities of its intake. Attention must be paid to the additives in foods or in medical supplies, whenever we appreciate the results of laboratory examinations.
