Comparison of two simple tests for the lupus anticoagulant

Area of Science:

• Hematology
• Clinical Chemistry
• Immunology

Background:

• Lupus inhibitors, also known as antiphospholipid antibodies, are associated with an increased risk of thrombosis.
• Accurate detection of lupus inhibitors is crucial for patient management and risk assessment.
• Current diagnostic tests have varying sensitivities for detecting these inhibitors.

Purpose of the Study:

• To compare the sensitivity of the kaolin clotting time (KCT) test and the dilute tissue thromboplastin inhibition (DTTI) test for detecting lupus inhibitors.
• To investigate methods for enhancing the sensitivity of the KCT test for lupus inhibitors.

Main Methods:

• Mixtures of patient lupus inhibitor-containing plasmas and normal plasma were tested.
• Concurrent testing was performed using both the DTTI test and the KCT test.
• The KCT test methodology was modified by reducing platelet phospholipid content, including using plasmas filtered through 0.22-micron cellulose acetate filters.

Main Results:

• The KCT test demonstrated higher sensitivity to the presence of lupus inhibitors compared to the DTTI test.
• Reducing platelet phospholipid content in the KCT test plasma significantly enhanced its sensitivity for lupus inhibitor detection.
• Filtration of plasma through 0.22-micron cellulose acetate filters also proved effective in reducing phospholipid content and increasing sensitivity.

Conclusions:

• The kaolin clotting time (KCT) test is a more sensitive assay for detecting lupus inhibitors than the DTTI test.
• Modifications to the KCT test, specifically reducing phospholipid content, can further improve its diagnostic sensitivity for lupus inhibitors.
• These findings suggest that an optimized KCT test could offer improved detection of lupus inhibitors, aiding in the diagnosis and management of associated conditions.