What diagnostic tests should be ordered to confirm a systemic lupus erythematosus (SLE) diagnosis?

To confirm a diagnosis of systemic lupus erythematosus (SLE), the most relevant diagnostic tests include a urinalysis, a tissue biopsy, and a complete metabolic panel. A urinalysis is crucial as it helps detect renal involvement, which is common in SLE; abnormalities in urine, such as protein or blood, can indicate lupus nephritis. A tissue biopsy, particularly of the skin or kidneys, can help identify specific lesions associated with SLE and provide histological evidence of the disease. The complete metabolic panel assesses organ function, electrolyte levels, and metabolic status, helping to monitor the effects of SLE on various bodily systems.

The other options do not contain the essential combination of tests that align specifically with diagnosing SLE. While a complete blood count can reveal anemia or thrombocytopenia common in SLE, it is not listed among the chosen tests, which emphasizes the need for tests directly indicative of lupus. An ECG is not typically relevant to SLE diagnosis, nor are imaging studies like X-rays and MRIs, which are more useful for assessing complications rather than confirming the diagnosis itself. Thus, the combination of urinalysis, tissue biopsy, and metabolic panel most accurately reflects the diagnostic approach for SLE.