PP2A (protein phosphatase) technique appears satisfactory for the analysis of DSP toxins in shellfish and is recommended as a rapid assay method for screening and end product testing.
This is one of the conclusions raised from a study carried out within the water project http://www.nppwater.com/index.php
Mussel samples from the biotoxins monitoring program carried by the Irish Marine Institute, Galway, were analysed. Samples were extracted from 3 sites (inner, middle and outer) from Killary Harbour, Ireland, in 2009 and 2010. Mussels from a DSP event were tested by Mouse Bioassay (MBA), ELISA (Abraxis), LC-MS and protein phosphatase PP2A assay (OkaTest).
ELISA kits showed matrix effects, but PP2A technique (OkaTest, ZEU-INMUNOTEC) was recommended as rapid assay.
More information on http://www.nppwater.com/data_access.php?id=85

The MicroCystest plate kit has been recently evaluated within the Environmental Technology Verification (ETV) Program. The E.P.A. supports the ETV program to further environmental protection by accelerating the acceptance and use of improved and cost effective technologies.

Recently, two papers have been published in Talanta and Analitical Chimica Acta comparing protein phosphatases (PP) from several sources (ZEU-INMUNOTEC, Millipore and GTP) and origin (recombinant or natural).