With such a large investment of time and money, purchasing a chemistry analyzer can be a daunting task.
There is such a variety of chemistry instruments and their claims, where do you begin? I hope I can help guide you in the right direction.
First of all lets figure out what you want. List the must-haves. The items you cannot live without. Then list your wants, would-likes, and can live withouts. Would you prefer benchtop or floor model. Does it matter?
The number tests per hour important. Is the quoted number of tests with or without ISE? Are the claims true? It is good to speak with someone who has one so that you can decide if the instrument is as fast as the manufacturer claims.
Decide how the system will be used. If you have many pediatric samples or stat tests that may be a key purchasing factor. Is your workload small, moderate or large and are you planning on expanding. Are you looking fo random access, batch or profile? Do you need special tests that are not available on certain units? Will your electrolytes be run on this instrument or will it be on a separate analyzer.
Make a list of the pros and cons of your current instruments and how the new system will complement them. If you are replacing an existing system why you are replacing it and what improvements do you need. Are you looking for faster or more capabilities. Be careful not to choose something too complex or expensive when you do not need it.
Maybe you are lucky enough not to be constricted by a price range but it is highly unlikely. There is no sense in wasting your time looking at instruments that you truly cannot afford. Are the extended capabilities on a more expensive unit justifiable for the extra money? Do you want disposable cuvettes or reusable? Is there a huge difference in the reagent cost? Can reagents other than the manufacturers be used on the unit or are you committed to the manufacturers only.
Begin to gather your data. I am sure you are familiar with quite a few systems but the perfect one for you now may be one you have never heard off. Keep your mind and your options open. Ask colleagues and contacts why they chose a certain instrument and which others they considered and why. Did they have a smooth start-up. Is the daily maintenance easy and as quick as the claims? What is the day to day precision like and are the reagents stable. Ask specifically for analytes such as calcium, phos, iron, as these tend to show carryover easily. Ask how quickly and efficient support is and the average downtime. Check cap proficiency survey and QC program data summaries to see how many labs are using the instrument and how consistent the results are. Investigate whether the instrument lives up to its claims. Be careful in evaluating the stated test/hr claim. Are they averaging all tests or running only the quickest. Are ISE’s included in this claim or is it just the photometric. How many test can be on-board is very important. You don’t want to be running things twice just to add a couple of other reagents. Check on the reagent storage and stability and the test menu. Compare the number, frequency and stability of calibrators, calibrations and QC. More calibrators mean better accuracy but do you need it? Evaluate the cost and time involved in calibrating. Enzymatic tests should have a good kinetic photmetric system taking multiple readings over a period of time and calculating the reaction rate. What is the market history? Are you willing to take a chance on a new system that has not been around for very long and may have unexpected problems. Will a new system be easy to service.
Is the ISE diluted or undiluted?
Time to narrow it down.
Are you searching for new, used or refurbished? You can usually save quite a bit of money on a refurbished system that can work just as well as a new one. In this case you would need to check on installation, training and service and support. Don’t assume you will get it or not get it. If it is not new does it come with a warranty?
At the end of the day if you are unsure which one is perfect for you…………..WAIT!!!
Even if you have to send some tests to a reference lab it is worth it to get exactly what suits your lab. Remember that you will have to live with your decision for many years (hopefully)