Table 1 Requirements for a uremic toxin

1. The toxin is a unique chemical entity.

2. Quantitative analysis of the toxin in biological fluids is possible

3. The levels of the toxin in biological fluids increase with deterioration of kidney function.

4. A positive relationship between toxin level in biological fluids and manifestations of uremic syndrome is present.

5. Administration of the toxin at concentration seen in patients with kidney disease shows toxic effects related to uremic syndrome both in vivo and in vitro.