When a microbiology sample arrives at the lab, then in order for it to get in through the front door, I expect it to be:

• Not leaking: The leaky sample is not only a potential infectious hazard to those handling it, it also implies that the sample itself is potentially contaminated.
• Properly labelled: The unlabelled sample is deceptively common (in my experience about 1-2% of all samples). The mismatched labelling of the request form and sample also occurs not uncommonly.
• In a proper container: I have seen stool samples arrive into the laboratory in Chinese Takeaway cartons and 35mm film cannisters, and get processed….
• Recently taken: Samples that take too long to get to the lab, for whatever reason, need to be discarded. Again I have seen samples “get lost in the post” for weeks, yet still get processed on arrival…

To keep things simple the general rule should be to reject such samples. Processing them is not only a medico-legal risk to the laboratory, it also presents a potential risk to the patient. Processing such samples also just perpetuates the problem. 

The general rule should be to reject, occasionally such samples fall into the “irreplaceable” or “difficult to replace” category, i.e. CSF, theatre samples. The clinical microbiologist should be informed, who then needs to make a clinical assessment as to the importance of processing.

How do you notify the requestor of a rejected sample? This depends on the importance of the sample: A rejected urine or wound swab etc etc I believe should be notified through the normal resulting channels. More critical samples that are rejected such as blood cultures, and other sterile site samples warrant a phone call.

Unfortunately there are still too many specimens getting into the microbiology laboratory that should never even make it past the front door. The laboratory must be the gatekeeper for what samples it deems acceptable and which ones it doesn’t. It seems tough but it is only because traditionally we have been too lenient in the past and just accepted whatever is thrown at us. I regard good rejection criteria documented in the (paperless) manuals as a key quality marker of any clinical microbiology laboratory…

Michael