| Abstract | dc.description.abstract | Although several tests are used to screen for the
presence of LA, none detects all its types. The shortening of APTT observed when the pre-incubation
period is prolonged, proved to be a sensitive test for the presence of LA. Material and
methods: We determined the APTT, performed with a 4 or 15 min preincubation period
(APTTs and APTT15 respectively), in 22 healthy subjects, 3 commercial positive controls for LA,
16 patients with a previous diagnosis of LA and 54 patients with recurrent fetal loss and/or infertility.
Evidence of LA was established by a positive Staclot-LA test. Results: APTTs and
APTT15 were 31.5±4.7 and 28.4±4.5 seconds respectively in samples from 22 normal subjects.
The figures in samples with LA, were 71.5±20.3 s and 58.6±18 s respectively. The difference between
the two APTTs performed on an individual sample was defined as the APTT 4-15 and
was 2.6±2.0 in normal subjects 2.5±2.8 in 13 patients anticoagulated with warfarin, -10.0±6.5
in 13 patients receiving heparin, and 13.2±4.9 in 15 patients with LA. The test values for LA
patients were significantly higher than those for normal subjects (p <0.0001). For values over 5,
the APTT 4-15 had 93.3% sensitivity and 100% specificity. In one patient with recurrent fetal
loss or infertility, who was LA positive, the APTT 4-15 was positive with a value of 14. Conclusions:
This modified TTPA is easy to perform, and provides a reasonably discriminatory value
for the presence of LA. Therefore, we recommend the TTPA 4-15 to screen for LA | en |
