What equipment do I need to run my BETMAT Bacterial Endotoxin Test (BET)?
Running a BET (Bacterial Endotoxin Test) (also called LAL test) requires a number of specialized reagents, consumables, and equipment to ensure accuracy, sensitivity, and to avoid contamination.
The Three Primary BET Methodologies of traditional LAL reagents.
The USP, Eur.P, and other pharmacopoeias recognize three main quantitative methods:
- Gel-Clot Technique (Traditional, Qualitative/Semi-Quantitative)
- Kinetic Turbidimetric Method
- Kinetic Chromogenic Method
- Equipment for the Gel-Clot Technique
This is the simplest method, based on the formation of a visible gel.
Essential Equipment:
Water Bath or Dry Bath Incubator: The most critical piece. It must maintain a very stable temperature, typically 37°C ± 1°C. A block heater with a tube rack is common.
Pyrogen-Free Glassware:
Specifically, 10x75 mm or 12x75 mm borosilicate glass test tubes.
Tube Racks: To hold the tubes in the water bath.
Timer: For accurate reaction and incubation timing.
Micropipettes and Sterile, Pyrogen-Free Tips: For precise aliquoting of samples, standards, and LAL reagent. Typically volumes of 100 µL are used.
pH Meter: To verify that the sample pH is within the acceptable range (usually 6.0 to 8.0) for the test, as extremes can inhibit the reaction.
Optional but Highly Recommended:
- LAL Reconstitution Station:
A rack to hold vials while reconstituting the LAL reagent to avoid contamination.
- Parafilm or Tube Caps:
To cover tubes and prevent evaporation during the incubation period.
- Key Takeaway for Gel-Clot:
The setup is relatively low-tech than other quantitative methods, it is traditional method with economical solution for BET.
- Equipment for the Turbidimetric & Chromogenic Methods
These are instrumental methods that provide quantitative results. The equipment list is similar for both.
Essential Equipment:
- LAL-Tested Spectrophotometer (Endotoxin Reader) with Incubator: This is the core instrument.
- It must be capable of reading kinetic reactions over time (kinetic assay).
- It contains a built-in, precise 37°C ± 0.2°C incubator to hold the reaction wells/tubes.
It uses specific wavelengths:
- Turbidimetric: Typically around 340 nm (to measure cloudiness).
- Chromogenic: Typically around 405 nm (to measure the release of a yellow chromophore).
Software:
The spectrophotometer is controlled by dedicated software that:
- Controls the instrument.
- Calculates the standard curve.
- Calculates the endotoxin concentration in the samples.
- Manages data for compliance (21 CFR Part 11 if required).
Pyrogen-Free Microplates or Cuvettes:
Microplates (96-well) are the modern standard. They must be certified pyrogen-free.
Alternatively, pyrogen-free glass or plastic cuvettes can be used.
Precision Micropipettes and Sterile, Pyrogen-Free Tips: Even greater precision is needed here. Multichannel pipettes are highly recommended for efficiency when using microplates.
Vortex Mixer: To ensure standards and samples are thoroughly mixed.
pH Meter: As with the gel-clot method, to check sample pH.
Optional but Highly Recommended:
- Automated Liquid Handler (Dilutor/Dispenser): For high-throughput labs, this automates the dispensing of LAL reagent, sample, and standards into the microplate, improving precision and efficiency while reducing repetitive strain.
- Endotoxin-Specific Software Modules:Many vendors offer software that is pre-validated for BET, simplifying setup and compliance.
Finally different detection methods require different detection instruments.
- For gel clot endotoxin testing, a 37ºC non-circulating water bath or a dry heat incubator is needed. The hole size of the dry heat incubator must match the size of the gel clot test tubes (usually 10X75mm) used.
- For quantitative endotoxin testing—including kinetic turbidimetric, kinetic chromogenic, end-point chromogenic, and rCR methods—BETMAT's incubating microplate reader Elx808BET is applicable. The Elx808BET is equipped with 405nm and 340nm filters. It also comes with detection software for processing kinetic data, supporting multiple methodological tests.
- For end-point chromogenic endotoxin detection, you can also use a microplate reader or spectrophotometer equipped with a 405nm filter. If the microplate reader does not have temperature control, a water bath or dry heat incubator is required to heat the reaction solution. During this process, attention should be paid to avoiding endotoxin contamination.
- For Recombinant Factor C (rFC) endotoxin testing, a incubating fluorescence microplate reader with 380/440 nm filters is required. In addition to the endotoxin detector, users also need a vortex mixer to mix endotoxins and a pipette (with endotoxin-free tips) for liquid transfer.