is probably the most widespread assay performed in microplates. The assay requires one or more steps including washing, dispensing, incubation, shaking and reading. It is widely used in research, food testing, diagnostics and in other fields. There are several factors that make ELISA automation very desirable:
- The operator can perform other tasks during incubations, manually performing the assay requires the operator to stay nearby for several hours and to abandon other tasks when the assay requires attention.
- Both, the accurate timing of the incubation steps and the reproducibility of the washing process are very important for the consistency and reliability of the assay. These steps are difficult to keep constant with manual operation.
- Higher throughput laboratories that need to analyze many plates per day would need more staff to provide the manual power required to perform the ELISAs.
Automation solves all these problems by increasing reliability and reproducibility, increasing throughput, freeing staff from repetitive tasks and allowing them to focus on other responsibilities. However, there are different forms of ELISA automation, so it is very important to choose the right instrument for the task.
Most instruments on the market offering ELISA automation have been designed to analyze immunoassays in large hospitals. These kinds of instruments can perform a large quantity of different assays per day. These instruments are bulky, expensive and require frequent and costly maintenance. ELISA kit manufacturers very often provide these instruments to support their applications and they have very little flexibility to perform assays from other manufacturers. They are typically sold alongside an agreement to purchase a large quantity of kits and these instruments are not always the best solution for customers other than large hospitals.
Automated ELISA systems by functions
All automated ELISA systems offer the basic functions needed to process an ELISA assay. These include, reagent dispensing, microplate washing, incubation and absorbance measurements. Some functions are not always available, and this is why it is important to know your exact requirements before purchasing any instrument:
- Sample handling: this includes sample dilution and sample transfer from tube to microplate, this often requires barcode reading for identification and tracking of samples. This can be very convenient when large quantities of samples must be processed it, and this makes the system much more complex. This increases the cost of the instrument and will require very high ongoing maintenance costs.
- Measurement of additional labels: while absorbance is the most popular label used in immunoassays, some assays use chemiluminescence or fluorescence. This requires either that the automated system can measure those labels, or the plate has to be moved to a suitable reader for quantification.
- Analysis of results: most ELISA kit manufacturers provide simple Excel spreadsheets to perform the calculations needed to get the results and for many users this is more than sufficient. However, in other cases more advanced software packages are required that enable a more complex analysis.
Automated ELISA systems by throughput
Another important distinction is the number of samples to be processed per day: low-throughput instruments are affordable and the perfect solution for laboratories processing only a few plates per day. While higher throughput laboratories need more sophisticated and expensive instrumentation to perform the job.
- Low throughput systems: these workstations are usually able to process a single plate only and often provide very basic functionality. They offer a solution for laboratories moving from manual processing to automation for the first time, or performing a rather low number of ELISAs per day.
- Medium throughput systems: these are instruments prepared to hold 2 to 3 plates and often include sample handling. They are the solution of choice for laboratories processing more than a few plates a day. An alternative to a single medium-throughput instrument is to use 2 or more low-throughput instruments working in parallel. The advantages are that different workflows are sometimes easier to handle in parallel and multiple instruments can serve as a backup in case one of them is down for maintenance or repairs.
- High throughput systems: these instruments can process 4 or more plates simultaneously (up to 16 is not uncommon) and include extensive sample handling capabilities. High-throughput Laboratories may need a custom automation or semiautomated solution enabling the required throughput.
There are many other microplate-based methods involving washing, dispensing, incubation and shaking can be automated using our workstations. For such workflows, most steps are automatically performed by the workstation and the final reading step is done in a specialized reader:
- Chemiluminescence immunoassays (CLIA) are very similar to an ELISA but instead of absorbance luminescence is measured in a .
- The approach is very similar for fluorescence immunoassays except the fluorescence is measured in a .
- ELISpot assays also involve several washing, dispensing and incubation steps, all of which can be automated. The spots are captured as a digital image using a special scanner or camera and then quantified using image analysis software.
- Microarrays have been traditionally performed on a slide. This enables the automation of the liquid handling and incubation steps. A microarray scanner takes care of the image acquisition.
Finally,is a method closely related to ELISA, this is automated very often.
Would you like to learn more about ELISA and our solutions for this assay? You will find plenty of information about it in ourApplication pages.