“Little and Large”

I have had some experience whilst working in New Zealand of Microbiology Laboratories that are too small. There are inherent difficulties in operating small microbiology laboratories.

  • Seeing enough of each sample type to maintain quality and expertise.
  • Reduced exposure to unusual organisms and resistance patterns.
  • Covering staff rosters, annual and sick leave etc.
  • Maintaining External QC.
  • Using kits before their expiry dates.
  • Cost per sample is increased.


There is no exact figure as to when a microbiology (Bacteriology) lab is too small to maintain quality, but I personally think some of the problems above start to arise when the sample volume is below about 50,000 per year. This is very much a ballpark figure.

But can a microbiology lab be too large?

Laboratories in general are getting larger all the time. The new multi-line track biochemistry analysers that are now coming in can literally analyse 1000s of samples a day, catering to a general population of well over a million. The limiting factor is getting the sample to the lab, and a transport time that is tolerable to the clinicians and the patients.

With Total Laboratory Automation on the horizon for microbiology, we are going to start seeing increased processing capacities for bacteriology labs, with the ability to process 1000s of samples a day.

However what are the downsides of such progress?

When thousands of samples are going through a laboratory there are a few potential disadvantages:

  • It may lead to lack of personal knowledge of particular patients of interest.
  • If the (automated) system breaks down for whatever reason then it may be difficult to transfer samples to a lab close by or to process the same number of samples manually.
  • The laboratory service may become less personal and relationships between lab staff and clinicians may become more detached.


While automation within microbiology laboratories should be embraced (not least because it is completely inevitable), efforts should also be made to counteract the potential difficulties as above. So how big is too big? Again this is a difficult question, but I suspect that once a microbiology (bacteriology) laboratory starts processing over a million samples a year then the factors above will start to become prominent.

It is important that in the transition to Total Lab Automation, a process which most microbiology labs will undergo over the next 5-20 years, our microbiology laboratories remain laboratories, and do not become factories….


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