High performance liquid chromatography allows simple quantification of TTX in urine and serum. Cases where urine and serum were tested for TTX indicate that serum concentrations of TTX fall rapidly and may be undetectable after 12-24 hours
However, TTX can be detected in urine for up to five days after ingestion and evaluation of TTX in a 24-hour urine collection
immediately after poisoning is likely to be the most sensitive test