Urine sediment evaluation is bland, without cells or casts.

The ultrasound shows kidneys of normal size without hydronephrosis or increased echogenicity.

While this is a reasonable, non-invasive test for renal artery stenosis (as is spiral CT  with CT angiography), clinical suspicion here is lower with normal bilateral kidney size and the absence of other underlying vascular disease. There is a better test to perform first. If work-up is otherwise unrevealing or the patient fails to respond to medical therapy, this may be a good next step.

A good choice! This patient’s plasma levels of metanephrine, norepinephrine, epinephrine, and dopamine are within normal. You even grab a 24 hour urine which is normal as well, but your patient didn’t enjoy collecting it!

Great choice! This patient’s PAC is 25 ng/dL (normal < 10ng/dL) and PRA is 0.5 ng/mL/hour (suppressed, < 1ng/mL/hour).

We might send this test if we suspected a connective tissue disease (CTD), like systemic lupus erythematosus (SLE). This patient’s initial presentation does not suggest SLE or other CTD. Try again!

This patient’s STOP-BANG score (a screening questionnaire developed by Chung et al for obstructive sleep apnea, OSA) is 2, which makes him low risk for OSA. Pick again!

This is a good initial test for Cushing’s syndrome, with most recommendations suggesting 2 measurements. However, 24 hour urine collection is cumbersome and requires effective education and counseling, and late-night salivary cortisol (2 readings) may be preferred. This patient’s urine free cortisol level is normal.

This cumbersome 24 hour urine collection test may not be necessary in this case, try a different test first! If the patient is undergoing 24 hour urine testing for other reasons, however, urine potassium level could be sent. In this case, the patient’s 24 hour urine potassium is 55 mEq/day.