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Ham's Test In Vivo?

Dale E. Hammerschmidt, MD; Patricia A. Coppo, MS; Harry S. Jacob, MD
JAMA. 1981;246(22):2574-2575. doi:10.1001/jama.1981.03320220026009.
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To the Editor.—  A 28-year-old woman with paroxysmal nocturnal hemoglobinuria (PNH) had a 5-cm cutaneous infarction and slough develop after the subcutaneous injection of meperidine (Demerol) hydrochloride for painful crisis. Noting that injectable meperidine may be provided at a pH as low as 3.5,1 we wondered whether an injection placed close to a skin feeder-vessel might yield enough acid-mediated complement activation to result in vascular occlusion through aggregation and lysis of complement-sensitive blood cells.Meperidine (5% solution) of the same manufacturer and lot number as had been given to the patient was obtained from the pharmacy. The addition of one volume of the drug to five volumes of normal serum reduced the pH to 6.7, very close to the pH used in Ham's acid hemolysis test2; furthermore, the total hemolytic complement in such serum fell by more than 70%, and C3 conversion became evident immunoelectrophoretically.3 When meperidine


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