Surreptitious ingestion of oral anticoagulants should be suspected in patients who exhibit an unexplained severe prolongation of the prothrombin time, have depressed levels of the vitamin K-dependent factors, and have previously been treated with oral anticoagulants or are associated with the medical profession.1,2
The definite diagnosis of misuse of oral anticoagulants is often difficult, particularly in the malingerer who tries to mislead the treating physician. Thus, precious time may be lost before appropriate treatment can be instituted. This report demonstrates the usefulness of spectrophotometric assays of plasma or serum extracts in the rapid identification and determination of dicumarol and warfarin sodium levels.3,4
MATERIALS AND METHODS
Blood was collected in siliconized aspirating syringes containing a mixture of citric acid-sodium citrate in a ratio of 9 volumes of blood of 1 volume of anticoagulant that were centrifuged for 20 min at 2,500 rpm. Coagulation assays were performed for the following:
Cole ER, Bachmann F. Spectrophotometric Assays for Warfarin Sodium and DicumarolUse in Rapid Detection of Patients Suspected of Drug Intoxication or Surreptitious Noningestion. Arch Intern Med. 1976;136(4):474–479. doi:10.1001/archinte.1976.03630040076016
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