In the different stages of laboratory testing (preanalytical, analytical and postanalytical), the preanalytical phase is a crucial one where errors can most commonly occur and affect laboratory results. These errors, occurring in various steps such as specimen collection, labeling or transportation, can also potentially harm patients.
"The phrase 'garbage in, garbage out' summarizes the effect of preanalytical errors," explains Christopher McCudden, PhD, NRCC, FACB, DABCC, assistant professor in the Department of Pathology and Laboratory Medicine at the University of Ottawa. "With laboratory data, 'garbage in' can result in erroneous results that can cause patient harm."
For example, a mislabeled specimen could lead to an inappropriate action, or lack of an appropriate one, Dr. McCudden says. Common issues in the preanalytical phase include:
- missing or wrong patient identification/labeling;
- inappropriate sample storage conditions;
- poor quality sample draw;
- collection in the wrong tube type;
- delay in delivery to the laboratory;
- inadequate mixing; and
- incorrect tube draw order.
A big obstacle to overcoming preanalytical factors is that many of them happen before a sample gets to the laboratory. "Thus, laboratory professionals are often blind to errors that occur before they receive the sample," Dr. McCudden tells ADVANCE. "When preanalytical errors are not detected, laboratory staff runs the risk of reporting erroneous results. Conversely, if laboratory staff makes assumptions about what results should be, they run the risk of rejecting specimens inappropriately." Dr. McCudden adds that this can cause conflict between lab and other staff members about whether there was an error and/or the source of an error.
Every member of a hospital team involved in specimen testing is responsible for preanalytical variation.
"While staff that actually draws specimens, such as phlebotomists, are in control of a large portion of the preanalytical process (patient identification, sample labeling, correct tube selection, draw order and transport), everyone should be aware of potential errors. Every step of the process is subject to potential error," says Dr. McCudden, who also is a clinical biochemist at The Ottawa Hospital.
Beyond laboratorians and phlebotomists, others who potentially could contribute to preanalytical errors include physicians and the patients themselves. Physicians need to know to order the correct test to get the result they are seeking, Dr. McCudden notes. The test orders also need to be linked to the appropriate patient, and the phlebotomist needs to be able to read the order. "Illegible handwritten orders with abbreviations run the risk of specimen mislabeling, patient misidentification and incorrect tests," mentions Dr. McCudden, who gives webinars on preanalytical factors for Radiometer America of Westlake, OH. He not only presents on the subject to laboratory professionals but also to nurses, medical students, medical residents and respiratory therapists, among others.
Patients also need to properly prepare themselves for testing so they don't negatively impact the preanalytical phase. "One common issue the laboratory will encounter is a non-fasting specimen where the patient should be fasting," Dr. McCudden says. "Even the most simple specimen collection is subject to preanalytical error. For example, a urine collection for cultures requires a mid-stream collection." Staff involved with specimen collection need to educate patients to avoid potentially harmful preanalytical errors. Other errors in the patient preparation process include patient identification, patient stability, patient activity, and site selection and preparation.
On the Frontline
Phlebotomists shoulder the majority of the burden when it comes to preventing preanalytical errors. They need to be aware of these issues "because if they don't, people will die," explains Dennis J. Ernst, MT(ASCP), executive director of the Center for Phlebotomy Education. "I'm not trying to be melodramatic here - it's absolutely true ... The laboratory tests hundreds of analytes, and they all can be altered by the manner in which the collector draws, handles, transports and processes the samples."
Three years ago at a biomedical conference in Oslo, Norway, Ernst declared a global war against preanalytical errors. "Every healthcare professional who draws blood, every manager who supervises them and every educator who teaches the procedure has to join the fight if we are to ever have a chance," Ernst stresses. "The enemies are many: complacency, misinformation, frustration, miscommunication ... We cannot underestimate the enemy, nor can we fail to recognize it when it rears its ugly head in our facilities."
"Preanalytical errors can be reduced by following good laboratory practice and regulatory guidelines," Dr. McCudden stresses. "All hospitals and labs may benefit from an analysis of their process to identify areas for improvement. Errors themselves provide excellent clues as to where and how a process has failed." It is up to administration to use these errors to reevaluate the process and find better ways to protect the patient.
Educating laboratory staff and medical personnel outside of the lab can help reduce preanalytical errors.
Amanda Koehler is a freelance writer.
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