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Time dependency of lupuslike anticoagulants
Archives of Internal Medicine
|May 1, 1988
Summary
Many lupuslike anticoagulants show time-dependent (TD) behavior, requiring incubation to detect their full anticoagulant activity. Activated partial thromboplastin time (APTT) tests can help predict TD inhibitors.
Area of Science:
- Hematology
- Clinical Chemistry
- Immunology
Background:
- Lupuslike anticoagulants are associated with thrombosis.
- Their detection can be challenging due to variable inhibitor characteristics.
Purpose of the Study:
- To investigate the prevalence and characteristics of time-dependent (TD) lupuslike anticoagulants.
- To determine if incubation is necessary for optimal detection of anticoagulant activity.
Main Methods:
- Retrospective review of 52 patients with lupuslike anticoagulants.
- Activated partial thromboplastin time (APTT) mixing studies with and without 1-hour incubation at 37°C.
- Comparison of preincubation (zero-minute) and post-incubation (60-minute) ratios.
Main Results:
- A time-dependent (TD) pattern was observed in 40% of cases.
- Anticoagulant activity was missed in 8% of cases when incubation was omitted.
- TD anticoagulants were more potent (mean APTT 74.1s vs 58.5s).
- APTT > 63s predicted TD behavior with 85% accuracy.
Conclusions:
- Many potent lupuslike anticoagulants require incubation for maximal activity detection.
- Omitting incubation may lead to missed diagnoses.
- APTT values can aid in predicting TD anticoagulant behavior.