<prompt> Which is the best test for Conn syndrome?Urinary metanephrinesPlasma aldosterone to renin ratioUrinary electrolytesRenal vein renin levels  <response>: IOC Best test for Conns syndrome: Salt-loading testSaline infusion test Screening test: Plasma aldosterone renin ratio In patient with conns syndrome, the plasma aldosterone levels dt tumor which causes endogenous production of aldosterone Therefore, Aldosterone levels are elevated, the RAAS system has negative feedback so Plasma Renin activity reduces. So Aldosterone Renin Ratio increased Since, Plasma aldosterone increased dt tumor Plasma renin Option D- Low renin levels are seen in Both Conns Liddles syndrome so only renal vein renin levels alone cannot be helpful for diagnosis. 