As I mentioned when this article first came out, it's important to be guided by the antibody testing included in the current classification criteria for whichever diagnosis you're considering. SLE, for example. Although antiphospholipid antibodies (aPL) are part of the 2019 EULAR/ACR classification criteria for SLE, Munawar & Sherazi found that only 15% of SLE patients are ever tested. Why?? The utility of aPL testing is well established, especially in late-onset disease: 1) Patients may require the 2 points conferred by aPL to reach the threshold for SLE classification/diagnosis; 2) All patients with a definitive SLE diagnosis require aPL testing for accurate cardiovascular risk stratification, regardless of whether they have a history of thrombosis or pregnancy complications. In this example, patients positive for aPL should be counseled regarding their additional risks, and shared decision-making as to appropriate prophylactic treatment should occur. Bottom line: Order the antibody testing included in the CURRENT classification criteria for the disease. Not doing so could lead to diagnostic delay or failure, and/or high-risk phenotypes could go unrecognized.