A 19- Year- Old College Student Was Evaluated for a Red

A 19- year- old college student was evaluated for a red rash on her face after a day at the beach. The student stated that the rash looked different from sunburn and that since she had been feeling generally unwell lately that she decided to have it checked out. Laboratory results were as follows. What is the most reasonable diagnosis and what follow- up testing is most appropriate?

Complete blood count (CBC) —slightly low red blood cells, platelets, and white blood cells
Urinalysis—2+ protein
Renal function tests (BUN and creatinine) —elevated
Liver function tests—within normal limits
Electrolytes and glucose—within normal limits
Antinuclear antibody (ANA) —positive, homogeneous pattern, titer 1:256
Total complement—decreased
Complement C3—decreased
Complement C4—decreased

A) Systemic lupus erythematosus/antiglomerular basement membrane antibody
B) Systemic lupus erythematosus/anti- DS DNA
C) Autoimmune hepatitis/antismooth muscle antibody
D) Goodpasture's syndrome/rheumatoid factor
E) Goodpasture's syndrome/antiglomerular basement membrane antibody