Saxitoxin (STX) is one of the most potent naturally occurring neurotoxins on earth — and one of the most regulated. Produced primarily by cyanobacteria in freshwater systems and dinoflagellates in marine environments, saxitoxin is the principal toxin responsible for paralytic shellfish poisoning (PSP). For environmental monitoring agencies, aquaculture operators, and public health labs, reliable saxitoxin detection is not optional. It is a regulatory requirement. Attogene offers a complete portfolio of saxitoxin detection kits spanning rapid lateral flow, laboratory ELISA, and molecular qPCR platforms — giving every monitoring team the right tool for their workflow.

Saxitoxin and its analogs — collectively referred to as paralytic shellfish toxins (PSTs) — are sodium channel blockers capable of causing rapid respiratory paralysis in humans at microgram-level exposures. Regulatory thresholds are strict: the FDA action level for saxitoxin in shellfish is 80 µg STX equivalents per 100 g of shellfish tissue, and the EPA has established health advisories for saxitoxin in drinking water at 0.3 µg/L for adults and 0.03 µg/L for children and bottle-fed infants.

Saxitoxin contamination events are driven by harmful algal blooms (HABs) — events that have become more frequent, more widespread, and more intense due to warming water temperatures and elevated nutrient loads. Filter-feeding shellfish such as oysters, mussels, clams, and scallops concentrate PSTs to dangerous levels from surrounding water, posing direct food safety risks. Freshwater systems, including reservoirs and source water intakes, are also increasingly at risk from saxitoxin-producing cyanobacteria including Aphanizomenon, Anabaena, and Cylindrospermopsis species.

Attogene’s saxitoxin testing product line addresses the full spectrum of monitoring needs — from rapid field screening to high-throughput laboratory quantification to molecular source confirmation. The right saxitoxin detection platform depends on your sample type, detection threshold requirements, and deployment environment. Below is a breakdown of the saxitoxin assay options available from Attogene.

Attogene’s lateral flow saxitoxin kits are engineered for speed, portability, and ease of use in the field. Results are typically available within 10–15 minutes without laboratory instrumentation, making these assays ideal for routine HAB surveillance, beach closures, aquaculture harvest decisions, and initial screening at water treatment intakes.

AU2057 — Saxitoxin PSP Lateral Flow Kit (Freshwater Streams and Source Water) is optimized for freshwater monitoring applications including streams, lakes, reservoirs, and drinking water source intakes. This assay is designed to detect saxitoxin and PST analogs in environmental water matrices, supporting compliance monitoring programs and real-time water quality surveillance.

AU2057-01 — Saxitoxin PSP Lateral Flow Kit (Shellfish Rapid Test — field deployable) is specifically validated for shellfish tissue matrices, providing a field-deployable rapid screening tool for aquaculture operations, harvest site monitoring, and shellfish safety programs. This assay format allows harvest managers and monitoring personnel to make rapid go/no-go decisions directly at the site without shipping samples to a central laboratory.

EL2048-02 — Saxitoxin (PSP) ELISA Kit provides quantitative saxitoxin measurement in a microplate format suited to central laboratory workflows. ELISA platforms are preferred when regulatory reporting requires a quantitative result, when sample throughput is high, or when confirmatory testing is needed following a positive rapid screening result. The Attogene saxitoxin ELISA kit is suitable for water and shellfish extract matrices and delivers the sensitivity needed to detect saxitoxin near regulatory action levels.

NA2027 — Saxitoxin qPCR Detection Kit (real-time PCR kit for the SxtA gene) targets the sxtA gene — a key biosynthetic gene in the saxitoxin gene cluster — allowing direct genetic detection of saxitoxin-producing organisms in water samples. This molecular approach is especially valuable for early detection of bloom-forming cyanobacteria before toxin concentrations reach actionable levels, giving water managers critical lead time for treatment or advisory decisions. It is also well suited for ecological research, bloom dynamics studies, and routine surveillance of source water supplies known to be at risk for PST-producing species.

The best saxitoxin detection method depends on what you need to know, how quickly you need to know it, and where the testing will take place. Here is a practical framework for matching platform to application.

Field screening and rapid response — Use the AU2057 or AU2057-01 lateral flow kits. These assays require no instrumentation, deliver results in minutes, and are stable under field conditions. They are the right tool for shoreline HAB response teams, aquaculture harvest site managers, and water utility operators needing immediate information.

Regulatory-grade quantification and confirmatory testing — Use the EL2048-02 ELISA kit. Quantitative ELISA data supports regulatory reporting, documentation for shellfish safety programs, and confirmatory follow-up after positive rapid test results. Central reference laboratories and state environmental labs will typically prefer an ELISA platform for these workflows.

Early warning and ecological surveillance — Use the NA2027 qPCR kit. Detecting sxtA gene presence allows monitoring programs to identify saxitoxin-producing organisms in the bloom before toxin accumulation reaches detectable concentrations by immunoassay. This proactive approach is particularly valuable for drinking water utilities and aquaculture operations that need to anticipate and manage risk rather than simply react to it.

Saxitoxin testing requirements span a wide range of sectors, and each has distinct operational needs that shape the choice of detection technology.

State and federal environmental agencies responsible for beach safety, recreational water advisories, and source water protection use saxitoxin detection kits as part of routine HAB monitoring programs. Rapid lateral flow assays enable quick response to bloom events, while ELISA kits support the quantitative data reporting required by state and federal programs.

Aquaculture and shellfish industry operators must test harvested shellfish tissue prior to sale or must close harvest areas when PSP levels are elevated. The AU2057-01 shellfish lateral flow kit provides the field-deployable, matrix-compatible testing tool operators need to meet food safety obligations and protect consumers.

Drinking water utilities monitoring source water quality for saxitoxin-producing cyanobacteria benefit from both the NA2027 qPCR early warning capability and the AU2057 rapid freshwater lateral flow kit, which together provide a multi-layer approach to PST risk management at source water intakes and treatment facilities.

Research institutions and academic laboratories studying HAB dynamics, toxin biosynthesis, or ecosystem responses to eutrophication use Attogene saxitoxin assays to support field sampling campaigns, ecological monitoring studies, and method validation projects. Browse the full Attogene product list or contact us to discuss your specific saxitoxin detection requirements.

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Saxitoxin is the parent compound of a family of over 50 structurally related toxins collectively called paralytic shellfish toxins (PSTs). Paralytic shellfish poisoning is the human illness caused by consuming shellfish or water contaminated with PSTs. Saxitoxin is the most potent member of the group and is the reference standard used in regulatory monitoring programs.

Attogene’s saxitoxin lateral flow kits are designed to detect saxitoxin and its structurally related PST analogs with varying degrees of cross-reactivity. The extent of cross-reactivity with specific analogs varies by assay format. For full cross-reactivity data and detection sensitivity specifications, refer to the individual product documentation or contact Attogene directly.

Attogene saxitoxin kits are available in formats validated for freshwater (lakes, streams, reservoirs, source water intakes), shellfish tissue extracts, and molecular applications using DNA extracted from water samples. The AU2057 is optimized for freshwater matrices, AU2057-01 for shellfish tissue, EL2048-02 ELISA for water and shellfish extract, and NA2027 qPCR for nucleic acid preparations from water samples.

Immunoassay methods (lateral flow and ELISA) detect the toxin molecule itself and are therefore dependent on toxin being present in the sample at detectable concentrations. The NA2027 qPCR kit detects the sxtA gene, which is a genetic marker for organisms capable of producing saxitoxin. qPCR can identify toxin-producing populations before toxin levels are detectable by immunoassay, providing an important early warning capability for water quality managers.

All Attogene saxitoxin detection kits are available through the Attogene online store. Visit the Attogene product list to browse available assay formats or contact Attogene for volume pricing, custom requirements, or technical support.