is probably the most widespread method, performed in microplates. The assay requires one or more steps of washing, dispensing, incubation, shaking and reading. It is widely used in research, food testing, diagnostics and other fields. There are several factors that make ELISA automation very desirable:
- While 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 his/her 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 more important tasks. 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. This kind of equipment is capable of performing a large quantity of different assays per day, but it is bulky, expensive and requires frequent and costly maintenance. In addition, ELISA kit manufacturers very often provide these instruments to support their applications. Thus, they have little flexibility to perform assays from other manufacturers, or are sold alongside an agreement to purchase a large quantity of kits during a given period of time. Hence, they are not always the best choice for customers other than large hospitals.
Automated ELISA systems by functions
All automated ELISA systems offer the basic functions needed to process an ELISA: reagent dispensing, microplate washing, incubation and absorbance measurement. But some other functions are not always available and, if you are looking to purchase a system for your laboratory, it is important to know if you require them or not:
- Sample handling: this includes sample dilution and sample transfer from tube to microplate. It often requires barcode reading for identification and tracking of samples. While this function can be very convenient if large quantities of samples have to be processed, it makes the system much more complex, and hence more expensive and maintenance-intensive.
- Measurement of additional labels: while absorbance is the most popular label used in immunoassays, some assays use chemiluminescence or fluorescence instead. This requires either that the automated system can measure those labels, or that the plate is 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. For many users this is fully 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. On the other hand, higher throughput laboratories do need more sophisticated and expensive instrumentation to perform the job.
- Low throughput systems: these workstations are usually able to process a single plate per run only and often provide just 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 instruments can serve as backup, in case that one of them is down for maintenance or repairs.
- High throughput systems: these instruments can process simultaneously 4 or more plates (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.
In addition to ELISA, 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, but in this case, fluorescence is measured in a .
- ELISpot assays also involve several washing, dispensing and incubation steps, which can be automated. The spots are captured as a digital image using a special scanner or camera, and quantified typically, using an image analysis software.
- Microarrays have been traditionally performed in slide format, but the need to increase the throughput is asking for a microplate format. This enables the automation of the liquid handling and incubation steps. A microarray scanner takes care of the image acquisition.
Finally,, a method closely related to ELISA, is automated very often.
Would you like to learn more about ELISA and our solutions for this method? You will find plenty of information about it in ourApplication pages.