Diagnosis:
Pre-analytical errors
• Errors can occur in any of the three phases of laboratory testing: (1) preanalytical, which begins with the patient and ends with preparation of the sample for testing; (2) analytical, which includes all steps involved in performing a laboratory test; and (3) postanalytical, which begins with reporting the results to the health care provider and ends with actions taken by the health care provider based on the test results.
• Most laboratory errors occur during phlebotomy and front-end processing of samples. The manual phlebotomy process – which involves collecting specimen labels, identifying the patient by examining the wristband, matching the labels with the patient, collecting blood using the correct order of draw, and correctly labeling the tubes – is highly susceptible to error. Standardizing the phlebotomy process can greatly reduce these errors.
• The most common sample processing errors are mislabeling the sample, incorrectly preparing aliquot samples (e.g., pouring from the wrong sample), mislabeling aliquot tubes, and misplacing samples in the laboratory. Automation of sample processing eliminates most of these errors.
• Errors in physician orders commonly happen because of the similarity of test names, lack of ordering physician knowledge about tests, duplicate orders, and transcription errors. The key to improving test ordering accuracy is to implement computerized order entry by the physician.
• Delays in transporting the specimen to the laboratory can compromise test results. To minimize postcollection variation, specimens should be delivered, processed, and stored promptly after collection. For example, glucose levels decrease at a rate of 5% to 7% per hour in whole blood maintained at room temperature. Transportation of specimens to the laboratory often significantly delays processing. Mechanical transport systems, typically with pneumatic tubes, are used by some laboratories to expedite specimen delivery.
• The concept of “critical values” refers to a pathophysiological state that can be life threatening for a patient unless appropriate therapy is initiated rapidly. Failure to report critical values expeditiously can compromise patient care and result in legal actions against the physician, the hospital, and the laboratory.
• Misinterpretation of test results means that the health care provider received the correct result but did not take the correct action based on the result. Interpretive reports can prevent this type of error and should include a description of the abnormal result, possible reasons for an abnormal result, suggestions for further testing, and a statement of need for treatment.
