Table 3.

Plasmatic and urinary osmolality and free water clearance before and after dilution/oral water load test in patients affected by SIADH or with a normal response (defined a posteriori)

	Baseline				Post dilution test (H3)				Diagnosis
	P Na+	P Osm	U Osm	Free H2O Cl. mL/min	PNa+	P Osm	U Osm	Free H2O Cl. mL/min
Group 3: Normal response to dilution
Patient 9	137	296	794	−1.07	133	285	201	1.34	Past history of SIADH
Patient 10	139	290	885	−2.77	138	286	132	3.97	Past history of SIADH
Patient 11	140	291	313	−0.15	139	285	104	4.03	Past history of water intoxication
Patient 12	137	286	915	−1.4	135	284	75	6.5	Past history of SIADH
Median	138	290.5	839.5	−1.23	136.5	285	118	4
Group 4:SIADH
Patient 13	132	277	460	0.59	127	268	591	0.28	SIADH
Patient 14	130	282	403	−0.76	130	277	613	−0.47	SIADH
Patient 15	132	275	322	−0.5	132	274	267	0.07	SIADH
Patient 16	139	306	580	−0.73	133	290	268	0.14	SIADH (partial response)
Patient 17	135	286	556	−1.75	133	274	308	−0.42	SIADH (partial response)
Patient 18	135	291	369	−0.6	130	277	281	−0.03	SIADH (partial response)
Median	133.5	284	431.5	−0.67	131	275.5	294.5	0.02
D	0.05	0.33	0.26	0.35	0.02	0.11	0.01	0.01

P Na⁺, sodium serum level; P Osm, plasmatic osmolality; U Osm, urinary osmolality; Free H₂O Cl, free water clearance; SIADH, syndrome of inappropriate antidiuretic hormone secretion.