Standard Operating Procedures for a Medical Microbiology Lab

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The medical microbiology laboratory helps health care providers discover and treat infections. As a result, the laboratory workers perform testing on potentially infectious materials and some very dangerous microbes. So it is essential that all laboratory personnel follow a standard operating procedure (SOP) which outlines every aspect of the work to be done in the lab.


First and foremost in the microbiology lab should be safety. Any good set of standard operating procedures must include information on standard precautions. Standard precautions involve the use of personal protective equipment (like gloves and gowns) and techniques (like handling of body fluids) to minimise the possibility of contamination or infection. For example, the SOP could read, "Use of gloves to handle culture dishes is mandatory. Only open and process samples under the laminar flow hood."


Laboratory results are only as good as the samples. If the samples are of bad quality, then the results will be invalid or not helpful in the treatment of the patient. The SOP should include what samples are acceptable for the different tests done in the microbiology lab. This includes describing how the sample should have been collected, how soon they should be delivered to the lab and what kind of special preparations should be done to them once they arrive. For example, the SOP could read, "Catheterized urine is the best specimen for a urine culture, followed by clean caught urine. Bagged samples or randomly collected samples should be avoided. All urine samples are to be processed within an hour of collection."


The SOP must include the procedures for performing any test that is done in the lab. This includes a step-by-step description of how the tests are performed and what the expected results are. The SOP should also describe any quality control testing performed along with other tests. Quality control testing is essential to ensure the validity of the results. An example of this would be a description of the strep throat screen: "Insert the sample swab into the test tube and add the reagents per the package insert of the testing kit. Wait 5 minutes. Remove the swab while allowing as much of the remaining solution to stay in the tube. Insert the testing strip and wait 3 minutes. After 3 minutes, read the results. Make sure that a result was noted in the quality control strip. Results are unacceptable if the quality control strip did not yield the expected results."


Finally, the SOP must include the appropriate format of the final report that is going to be sent out to the provider who ordered the test. The report must include the testing results, normal (expected results), and any interpretation of the results that is necessary. If any of the test results are deemed to be "critical," the SOP must address how those critical results will be reported and to whom. For example, "All positive results on a cerebrospinal fluid sample must be reported to the attending physician or the physician on call immediately. Do not leave a message with clerical staff and do not finalise the report until you note who received the critical message and what time that message was delivered."

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