A method of determining whether to classify a patient as exhibiting an increased risk of developing Lupus, comprising, by a processing device: receiving a set of blood sampling data for a patient who exhibits less than four classification criteria for Lupus, wherein (i) the patient is determined to meet two or three classification criteria for Lupus; (ii) the set of blood sampling data comprises a plurality of cell-bound complement activation product (CB-CAP) levels for the patient; (iii) the CB-CAPs comprise at least eight of the following E-C4d, E-C3d, R-C4d, R-C3d, T-C4d, T-C3d, B-C4d, B-C3d, M-C4d, M-C3d, G-C4d, G-C3d, and P-C4d; (iv) the classification criteria are those of the American College of Rheumatology and consist of arthritis, malar rash, discoid rash, photosensitivity, oral ulcer, serositis, neurologic disorder, renal disorder, presence of anti-nuclear antibodies, serologic disorder, hematologic disorder; accessing a control data set, the control data set comprising a control level for each of the CB-CAPs; comparing the CB-CAP levels for the patient with the control levels to determine a number of the CB-CAPs for which the patient's levels are elevated as compared to the control levels if the determined number exceeds a threshold, classifying the patient who exhibits less than four classification criteria for Lupus and who was determined to meet two or three classification criteria for Lupus as exhibiting an increased risk of developing Lupus; and generating a report comprising an indication of whether the patient is classified as exhibiting the increased risk of developing Lupus. receiving a set of blood sampling data for a patient who exhibits less than four classification criteria for Lupus, wherein (i) the patient is determined to meet two or three classification criteria for Lupus; (ii) the set of blood sampling data comprises a plurality of cell-bound complement activation product (CB-CAP) levels for the patient; (iii) the CB-CAPs comprise at least eight of the following E-C4d, E-C3d, R-C4d, R-C3d, T-C4d, T-C3d, B-C4d, B-C3d, M-C4d, M-C3d, G-C4d, G-C3d, and P-C4d; (iv) the classification criteria are those of the American College of Rheumatology and consist of arthritis, malar rash, discoid rash, photosensitivity, oral ulcer, serositis, neurologic disorder, renal disorder, presence of anti-nuclear antibodies, serologic disorder, hematologic disorder; (i) the patient is determined to meet two or three classification criteria for Lupus; (ii) the set of blood sampling data comprises a plurality of cell-bound complement activation product (CB-CAP) levels for the patient; (iii) the CB-CAPs comprise at least eight of the following E-C4d, E-C3d, R-C4d, R-C3d, T-C4d, T-C3d, B-C4d, B-C3d, M-C4d, M-C3d, G-C4d, G-C3d, and P-C4d; (iv) the classification criteria are those of the American College of Rheumatology and consist of arthritis, malar rash, discoid rash, photosensitivity, oral ulcer, serositis, neurologic disorder, renal disorder, presence of anti-nuclear antibodies, serologic disorder, hematologic disorder; accessing a control data set, the control data set comprising a control level for each of the CB-CAPs; comparing the CB-CAP levels for the patient with the control levels to determine a number of the CB-CAPs for which the patient's levels are elevated as compared to the control levels if the determined number exceeds a threshold, classifying the patient who exhibits less than four classification criteria for Lupus and who was determined to meet two or three classification criteria for Lupus as exhibiting an increased risk of developing Lupus; and generating a report comprising an indication of whether the patient is classified as exhibiting the increased risk of developing Lupus.