If you are in the market for a new tissue processor, the options can seem daunting.  Not only is there a dizzying array of machines to choose from (most of which look very similar at face value), but both suppliers and manufacturers will assure you that their machine is perfect for your particular lab.  So, what’s really out there?  How can you be sure that you have chosen wisely, and that the machine you are looking at really measures up to any cost benefit analysis?

Firstly, let’s deal with the issue of reliability.  Many labs will have developed their own preconceptions about which manufacturer can be relied upon in terms of the best machines.  This is often based on the fact that ‘we’ve had an x for the last 20 years, and it’s never given us any problems’.  But things have moved on.  Although processors are now more advanced technologically, their basic function is no longer rocket science – and it is difficult to rule any particular machine out in terms of reliability alone.  Instead, ask about the supplier’s support package, including fault detection and response mechanisms and the speed at which they will be able to get an engineer to you, should it be necessary.

The next item to tick off the list is capacity.  The Leica Peloris III double retort is by far the market leader in this respect with 600 sample capacity (300 in each retort).  Plus, the double retort allows two different protocols to run at the same time.  If you have a busy lab running numerous protocols, there is simply no directly comparable machine.  The ability to run simultaneous processes is also demonstrated by the Sakura Xpress X120 which has an impressive 4 chamber processing capacity (running 50 samples per chamber).  With both machines, it is only worth remembering that if this is your only machine, should it suffer a fault, all your tissue processing capability would be stalled until it was back on line.  Plus, these are amongst the most expensive machines on the market.

Next in line in terms of capacity is the Diapath Donatello, with an impressive 405 sample capacity in a single retort.  This nifty processor, developed by histologists, is also buzzing with some smart technology, including an intelligent alert system, automated specimen protection and special ‘bubbling’ mechanism to improve reagent infiltration and sample quality.  Even if you think you don’t need all the added extras, with a relatively cost-effective price tag (and ticking the box across almost all of the special features offered by the full range of its competitors), this machine could be a handy way of ‘future-proofing’ your lab.

Most other machines, including the very popular Leicas ASP300S and ASP6025, have a capacity of 200-300 and have processing times from 2 to 8 hours depending on sample size and protocols.  There are one or two machines, including the Jokoh Histra-GT, which uses ultrasonic technology to decrease processing times to less than 2 hours.  However, this machine has a capacity of 100, and is ideal for processing very small samples, working in a specialist laboratory setting.  Most other machines use microwave technology to cut processing times, with one or two pre-heating their regents instead (including the impressive Thermo Shandon’s Excelsior) – but don’t expect miracles: processing times for standard sized samples are still likely to run into several hours, with only the very smallest biopsies returning processing times in 2 hours.

There have been a number of papers published on the use of reagents and in particular the balance between reagent usage and sample quality.  Gone are the days of keeping a log book of processes versus regent use.  Modern machines will keep this record for you.  Many, including Sakura’s VIP Tissue-Tek, offer a closed system which keeps a record of reagent usage and prompts optimum replenishment – also preventing any human error when refilling.  This is usually balanced with an open option, to maximise versatility.

The Histo-Pro 300 from Histoline and Donatello also offer the option of using non-traditional, less hazardous reagents as an option, which may prove important as laboratories consider their environmental footprint more seriously in the future.

The Bio-Optica Conventionale (VTP300) could be seen as a great all-rounder, and demonstrates the advantages of a no-frills machine.  It has all the key features you would expect, including a 300 capacity retort and a paraffin purification system, but the reagent tanks are quite small, and there are no technological features which many others now offer, such as sample protection in the event of a power outage; waste management systems and sample tracking interfaces.

Of course, nothing beats trialling the machine in situ.  You should insist on a free demonstration before committing to any machine and this should help crystallise your decision-making process.  But being armed with some of the above information may help you to decide which machine would best suit your particular lab life needs and, ultimately, help you to run the most efficient laboratory.



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