Clinical Application of Revised Laboratory Classification Criteria for Antiphospholipid Antibody Syndrome: Is the Follow-Up Interval of 12 Weeks Instead of 6 Weeks Significantly Useful?
Background. According to revised classification criteria of true antiphospholipid antibody syndrome, at least one of three antiphospholipid antibodies should be present on two or more occasions at least 12 weeks apart. However, it can be inconvenient to perform follow-up tests with interval of 12 weeks. We investigated clinical application of follow-up tests with interval of 12 weeks. Method. Totals of 67, 199, and 332 patients tested positive initially for the lupus anticoagulants confirm, the anti-β 2 glycoprotein-I antibody, and the anti-cardiolipin antibody test, respectively, from Jan 2007 to Jul 2009. We investigated clinical symptoms of patients, follow-up interval, and results of each test. Results. Among patients with initial test positive, 1.5%-8.5% were subjected to follow-up tests at interval of more than 12 weeks. Among 25 patients with negative conversion in tests, patients with interval of more than 12 weeks showed clinical symptom positivity of 33.3%, which was higher than that of 12.5% with 6-12 weeks. Among 34 patients with persistent test positive, clinical symptoms positivity trended to be more evident in patients at interval of 6-12 weeks (47.4% versus 26.7%, P = 0.191) than more than 12 weeks. Conclusion. Less than 10% of patients with initial test positive had follow-up tests at interval of more than 12 weeks and the patients with persistent test positive at interval of more than 12 weeks showed trends toward having lower clinical symptoms than 6-12 weeks. More research is needed focused on the evidence that follow-up test at interval of more than 12 weeks should be performed instead of 6 weeks.
Department of Laboratory Medicine, Pusan National University College of Medicine, Pusan National University Hospital, Busan 49241, Republic of Korea; Biomedical Research Institute, Pusan National University Hospital, Busan 49241, Republic of Korea.
Sang Hyuk
SH
Park
Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul 05505, Republic of Korea.
Seongsoo
0000-0002-0045-1747
S
Jang
Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul 05505, Republic of Korea.
Chan-Jeoung
CJ
Park
Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul 05505, Republic of Korea.
Hyun-Sook
HS
Chi
D017152:Antibodies, Antiphospholipid / Q000097:blood*; D016736:Antiphospholipid Syndrome / Q000175:diagnosis*; D005500:Follow-Up Studies; D006801:Humans; D012016:Reference Values; D012189:Retrospective Studies; D013997:Time Factors
D017152:Antibodies, Antiphospholipid