A method of determining whether to classify a patient as exhibiting an increased risk of developing Lupus, comprising: receiving in vitro a blood sample for a patient who is determined to meet fewer than four classification criteria for Lupus; wherein the classification criteria are those of the American College of Rheumatology (ACR) and consist of arthritis, malar rash, discoid rash, photosensitivity, oral ulcer, serositis, neurologic disorder, renal disorder, presence of anti-nuclear antibodies (ANA), serologic disorder, hematologic disorder; performing cell-bound complement activation product (CB-CAP) assays on the blood sample to generate a set of blood sampling data for the patient; wherein the CB-CAP assays comprise a panel of assays using monoclonal antibodies specifically reactive with at least two of the following CB-CAPs: E-C4d, R-C4d, P-C4d, T-C4d, B-C4d, M-C4d, and G-C4d, and wherein the set of blood sampling data comprises levels of at least two of the CB-CAPs for the patient; comparing the CB-CAP levels for the patient with a set of normal control levels to determine the CB-CAPs for which the patient's CB-CAP levels are elevated as compared to the control levels; generating a score for the patient based upon a number of CB-CAPs for which the patient's CB-CAP levels exceed the control levels by at least a threshold amount; determining whether the patient's score is greater than an average score for other subjects, exhibiting immune and/or inflammatory diseases that are not Lupus and if the patient's score is determined to be greater than the average score for the other subjects, classifying the patient as exhibiting an increased risk of developing Lupus. receiving in vitro a blood sample for a patient who is determined to meet fewer than four classification criteria for Lupus; wherein the classification criteria are those of the American College of Rheumatology (ACR) and consist of arthritis, malar rash, discoid rash, photosensitivity, oral ulcer, serositis, neurologic disorder, renal disorder, presence of anti-nuclear antibodies (ANA), serologic disorder, hematologic disorder; performing cell-bound complement activation product (CB-CAP) assays on the blood sample to generate a set of blood sampling data for the patient; wherein the CB-CAP assays comprise a panel of assays using monoclonal antibodies specifically reactive with at least two of the following CB-CAPs: E-C4d, R-C4d, P-C4d, T-C4d, B-C4d, M-C4d, and G-C4d, and wherein the set of blood sampling data comprises levels of at least two of the CB-CAPs for the patient; comparing the CB-CAP levels for the patient with a set of normal control levels to determine the CB-CAPs for which the patient's CB-CAP levels are elevated as compared to the control levels; generating a score for the patient based upon a number of CB-CAPs for which the patient's CB-CAP levels exceed the control levels by at least a threshold amount; determining whether the patient's score is greater than an average score for other subjects, exhibiting immune and/or inflammatory diseases that are not Lupus and if the patient's score is determined to be greater than the average score for the other subjects, classifying the patient as exhibiting an increased risk of developing Lupus. <EOS>