Background The SLE-key® test was developed by ImmunArray and was validated to rule out SLE with 94% sensitivity, 75% specificity and a negative predictive value (NPV) of 93%¹. We reported earlier that the SLE-key® RuleOut test could aid in the diagnosis and disposition of a cohort of 55 patients in our clinical practice².

Objectives We have now expanded this cohort and report here the usefulness of the SLE-key® test in aiding the management of a cohort of challenging and suspected SLE patients in a large clinical practice.

Methods In patients referred to the Rheumatology and Immunotherapy Center, in Franklin, WI, results from the SLE-key® RuleOut test were included as part of the clinical evaluation. Serum samples were collected from individual subjects with informed consent and tested at VERACIS (Richmond, VA), using the SLE-Key® iCHIP®¹.

Results We reviewed the diagnoses and clinical disposition of patients both before and after SLE-key® testing. In particular, we looked at the ability of the SLE-key® test to enhance our ability to reach a definitive diagnosis across the full cohort of patients, at the disposition of patients who were referred with a suspicion of SLE as part of the differential diagnosis, at the impact of SLE-key® testing on the diagnosis of the subset of patients who presented with minimal symptoms, and at the group of patients who had been referred following an ANA test. Results are summarized in Table 1. In the cases where SLE was ruled out, patients were treated for a variety of disorders including fibromyalgia, joint pain, MCTD, Sjogren's disease and others.

Conclusions The diagnosis of patients referred in the clinical rheumatology setting remains an ongoing challenge. The SLE-key® RuleOut test provides a laboratory aid to improve the diagnostic and dispositive efficiency saving undue concern, time and resources both to the patient and to the healthcare system. A retrospective analysis of our practices prior to the introduction of SLE-key® is warranted.

References

1. Putterman et al., Journal of Immunological Methods, 2016.

2. Massenburg et al., Arthritis Rheumatol. 2016; 68 (suppl 10).

References

Disclosure of Interest None declared