A 37year-old male diagnosed with hypertension has been treated with a low sodium diet and hydrochlorothiazide (HCTZ) 50 mg qd for the past two months. He denies Family history of cardiovascular disease. At today's follow-up visit his BP=150/90 and T=I00 F. Physical examination reveals no bruits, clear chest, no atrial gallop, edema and tenderness of the left ankle, and an intact neurological system. Which laboratory values will provide the most useful follow-up information

- To measure the 8-isoprostane concentration in plasma. It is possible to determine its level by using the ELISA (Enzyme-Linked ImmunoSorbent Assay) assay.

- To measure the nitrite and nitrate concentrations, which may also be associated with an increased risk of cardiovascular disease. The Griess reaction is specific for nitrite (and thereby it can be used to determine its level), while deproteinization methods enable to calculate the nitrite concentration.

You can read the following publication with detailed information about the methodologies above described:

P. S. Silva, V. Fontana, A.C. Palei, J.T. Sertório, C. Biagi, & J. E. Tanus-Santos (2011). Antihypertensive effects exerted by enalapril in mild to moderate hypertension are not associated with changes in the circulating levels of nitric oxide-related markers. European journal of clinical pharmacology, 67(4), 365-370.