How Important is a Laboratory Test Result?

Proper procedures are absolutely crucial when evaluating and diagnosing a patient. The results of lab tests affect the decision-making process that medical professionals go through when formulating the best strategy for treatment, not to mention their role when doctors inform patients about their illness or lack thereof! If lab tests are mistaken, the patient’s health will be compromised and the situation can escalate to a life-threatening level.

There are many standard operating procedures, resources, supplies, and equipment involved in a lab test. Without the proper tools, every level of patient care thereafter will, in all likelihood, be a mistake.

As the results from the work ‘Factors that can affect laboratory investigations‘ published in The Best Practice Advocacy Centre explains: “If a sample is being collected at the practice, it is important to be familiar with the type of collection container and sample medium that is required by the laboratory for the specific test, as this can affect results, sometimes markedly. For example, a swab for PCR testing for pertussis should be transported in a dry tube or a tube with a universal viral transport medium, but not in a tube with charcoal transport medium (which is acceptable for swab culture).” 1

The American Association for Clinical Chemistry (AACC) on their publication ‘How Reliable is Laboratory Testing’ regarding specific requirements established by the US Food and Drug Administration (FDA) perfectly indicates that:

“All laboratory test methods must meet scientifically rigorous criteria before they can be used in clinical practice. For commercial tests in the U.S., the Food and Drug Administration (FDA) reviews the scientific evidence to ensure that:

  • The test is accurately able to detect or measure the substance it claims to detect or measure, and
  • The measurement or detection of this substance provides important information about an illness or about health status that assists in the diagnosis, treatment, or monitoring of a patient.

A laboratory must demonstrate that it is able to perform that test in a clinically acceptable way. State and federal regulatory agencies monitor the laboratory and set standards that a laboratory must meet in order to be allowed to perform the test. Some of these standards are:

  • Laboratories must perform routine quality control tests, usually every day, and in many cases, several times a day. Quality control tests usually include normal and abnormal samples to ensure that the equipment, the technologist, and the reagents used in the test are performing to established standards.
  • Laboratories must participate in proficiency testing programs in addition to quality control testing. For proficiency testing, an external agency sends “challenge” samples to be tested. The laboratory must report results back to the agency. The agency has already evaluated each of the challenge samples and knows the expected results. This evaluation also compares results to other participating laboratories, noting similarities or differences that may be attributed to the testing methodologies used. The laboratory must get the right result in order to be allowed to continue to test patient samples. If the lab repeatedly fails to get the right result, it is prohibited from continuing the performance of that test until it can demonstrate that it has corrected the problems that led to the unacceptable results.
  • Laboratories must demonstrate that they have written policies and procedures in place to specifically document how the sample is collected, transported, evaluated, and reported in an appropriate manner.

These requirements ensure that the tests performed by clinical laboratories for patient care will generate results that are reproducible and can be trusted.2

According to statistics, 1.5 out of 20 adults in the US receive a test result with incorrect information. As you can see, errors are more common than you may think. More than 12.5 billion tests are carried out in clinical laboratories every year in the US and based the aforementioned statistic, it means that false lab results account for just under 1 billion lab tests per year.

As results from Scientific American statistical investigations show on their work ‘What Everyone Should Know About Lab Tests’: “In the United States, some 251,000 deaths per year occur because of errors in medical care. This makes medical errors the third leading cause of death, only after heart disease and cancer. Though this is alarming and concerning, it highlights a much larger problem, as many medical errors aren’t lethal.”

Medical error are defined as “an act of omission or commission in planning or execution that contributes or could contribute to an unintended result.”3

 

Also, according to laboratory samples quality control information provided by the AACC   (American Association for Clinical Chemistry):

“Laboratory testing is subject to many factors that potentially could adversely affect the integrity of the sample and prevent the timely reporting of an accurate test result to your provider. Typically these are grouped into three areas that track the sample from beginning to end of the process.

  • Pre-Analytical is the term used to describe things that happen from the time the test is ordered to the time the sample arrives in the lab.
  • Analytical is the term used to describe the things that happen during the handling and analysis of the sample in the laboratory.
  • Post-Analytical is the term used to describe what happens after a result is obtained and includes how and when it is reported to your provider.

 

Pre-Analytic Activities
From the time a test is ordered, a chain of events is set into motion. All these steps must be done the right way to ensure that an acceptable sample arrives at the lab. The following are some of the areas where errors can occur, even though standard procedures are in place to prevent such errors.

  • Test ordering process – the provider must order the correct test using the correct test name or code.
  • Patient preparation for the test – the patient should have received appropriate instructions about diet, fasting, medications, etc. to ensure that the sample will not contain substances that interfere with the test.
  • Patient identification – the person collecting the sample needs to confirm that the person is indeed the patient on whom the test was ordered. In hospitals, this means checking for a wristband and confirming proper identification of the patient. When you are asked to give your name and some other identifying information, it is to ensure that you and your sample are correctly matched. If this isn’t done when a sample is taken, make sure you check to see that your sample is identified correctly.
  • Completeness of patient information – the sample must be carefully labeled with two identifiers (usually patient name and date of birth or medical record number and the date of service) to ensure that the sample is associated with the correct patient. A hard copy requisition or electronic version must accompany the specimen and includes the tests ordered, patient’s demographics, ordering practitioner’s demographics, date of service, and the phlebotomist’s identification.
  • Specimen collection procedures – the sample must be collected in the correct type of container and mixed with the right preservative, when appropriate. The laboratory staff who collect samples receive special training on how to collect samples for each kind of test.
  • Transport to the lab – some samples need to be kept cold, while some need to be processed and tested within a limited time, so careful handling and prompt transportation are important components to sample integrity. In addition, ambient temperatures during transport, with extremely hot or cold weather, may also have an impact on specimen integrity and must be addressed accordingly.4

Many incorrect lab results occur, as The Best Practice Advocacy Centre specifies, due to an incorrect collection, transportation and handling of the samples. And as they explain:

  • “Blood samples for coagulation studies, including platelet count, D-dimer, prothrombin time, APTT and fibrinogen, should be transported to the laboratory within four hours of collection6
  • Urine specimens for culture should be stored in a fridge prior to transportation to reduce the rate of multiplication of microorganisms.
  • Samples for glucose analysis should be separated as soon as possible after collection; this applies even with samples collected in fluoride or oxalate collection tubes, as a reduction in glucose concentration still occurs for 60–90 minutes.
  • Samples for potassium or phosphate should not be left overnight, especially in the fridge, as results can be markedly altered, e.g. late evening collection with delayed transport to the laboratory.
  • Fecal samples for culture and microscopy should preferably be transported to the laboratory within four hours.
  • Semen samples for fertility testing should be kept by the patient at body temperature, e.g. by storing in a clothing pocket and transported to the laboratory within one hour of collection. The same level of urgency is not required for post-vasectomy semen analysis.” 5

 

Many people have been told they have a disease after an incorrect reading, making the patient worry unnecessarily, causing negative psychological consequences. This is why it is recommended to ask for a second opinion when a gloomy diagnosis is received. Imagine being incorrectly diagnosed with a terminal disease that never was. How would receiving bad news dictate your actions? False information can have the same influence on a patient’s life as real ones, especially with regards to treatments and the financials involved in dealing with a disease. The impact on your life can be massive if the lab tests turned out to be incorrect or inaccurate.

The American Society for Clinical Pathology on their Lab Medicine publication states that: “Laboratories have spent decades improving analytical quality by establishing internal quality controls (IQC) and external quality assessment (EQA). The role of EQA and proficiency testing (PT) is to provide reliable information allowing laboratories to assess and monitor the quality status of internal procedures and processes, the suitability of the diagnostic systems, the accountability and competence of the staff, along with the definition of measurement uncertainty in laboratory results. The responsibility of laboratory professionals is to appropriately analyze EQA/PT samples and reports, detect trends or bias that may not be apparent in single results, investigate root causes producing unacceptable performances, apply and monitor opportune actions for removing the underlying cause(s), verify the effectiveness, and, above all, determine whether the problem affected clinical decision making.6

 

Some medical facilities have mistaken the patient’s records for another or performed tests to the incorrect patient. If one inaccuracy can affect the outcome of treatment negatively, imagine what would happen if a triple blunder transpired: an inaccurate result from an incorrect procedure for the wrong patient!

As The Best Practice Advocacy Centre describes in ‘Best Tests investigation results’ in the laboratory investigation ‘Factors that can affect laboratory investigations’, it can also be a matter of: “selecting the right test, at the right time, for the right patient. After making the decision that an investigation is necessary, and selecting the most appropriate test, consideration must be given to what factors are present that may affect the interpretation of results, or even the decision to proceed with the test at that time.” 7

 

It is important for patients and family members to ask the laboratory professional that is taking the sample: What is the test for? This is a normal question and they are under obligation to explain why the test needs to be performed. If there has been a mistake with the ordering of the exam, that simple inquiry may nip any issue in the bud before it even begins.

The National Academies of Sciences, Engineering, and Medicine states, you need to:

  • Be an Informed Consumer.
  • Learn about your illness.
  • Know the names of your medications (both generic and brand names). For example, Tylenol (brand name) and acetaminophen (generic name) – Know what the medication is for.
  • Make sure about the amount (dose) you need to take.
  • The time(s) you need to take it during the day.
  • The side effects to watch for and report to your clinician.
  • If the medication interacts with any food or drugs.8

Make sure you have the correct instructions prior to the test. Double check with your doctor or the laboratory professional to be sure what you should and shouldn’t do. Patients not following instructions before taking a lab test is one of the most common reasons test errors occur, not because of a mistake on the lab’s part.

The National Academies of Sciences, Engineering, and Medicine on their report ‘Improving Diagnosis in Health Care’ clearly indicates important steps you need to follow to help achieve proper diagnosis starting with “Effective communication and collaboration among all members of the diagnostic team are essential to improve health care and outcomes and to reduce the risk of diagnostic error. Although there are a number of challenges to patient engagement in the diagnostic process, a critical step is for healthcare professionals and organizations to create environments in which patients and their families can learn about the diagnostic process and feel comfortable participating in this process.”  

First of all, the National Academies Organization states that: “it is very important to: Know Your Test Results.

  • Make sure both you and your clinician get the results from any tests that are done.
  • Don’t assume that no news is good news; call and check on your test results.
  • Ask what the test results mean and what needs to be done next. Follow Up.
  • Ask when you need to make another appointment (follow up) with your clinician once you start treatment.
  • Ask what to expect from the treatment or what it will do for you.
  • Ask what you need to do if you get new symptoms or start to feel worse. Make Sure It Is the Right Diagnosis.
  • Don’t be afraid to ask “What else could this be?”

After your clinician diagnoses your condition, ask if it could be something else. Make sure you understand what is causing your symptoms. In your own words describe the diagnosis back to your clinician.

  • Encourage your clinicians to think about other possible reasons for your illness.”
  • Inviting someone to go with you.

Bringing someone to your appointment can help you to answer questions and give your clinician information. 9

 

“In order for the laboratory to have a positive impact on diagnostic errors, it is necessary to become part of the interdisciplinary patient-centered care team. Laboratory professionals need to view their services as contributing to patient outcomes, not just generating results.  Research on diagnostic errors and the laboratory’s role has found that failure to order appropriate diagnostic tests, including lab tests, makes up 55% of missed and delayed diagnoses in the ambulatory setting and 58% of errors in emergency departments. This statistic underscores the need for Clinical Lab Scientists to interact with and provide education to ordering providers on the proper use of the testing we provide. One way that clinical laboratory professionals can affect positive change is by collaborating with other healthcare providers to establish evidence-based decision-making guidance for ordering tests. Providing feedback to providers detailing improper test utilization patterns, both over- and under-utilization, is another way that laboratory professionals can help to reduce diagnostic errors.” As stated by the As Lab Testing Matters Organization states.10

 

As you can see, accurate laboratory test results may be affected due to different reasons. From the patients’ perspective, it is vital to follow all the indications provided by medical professionals to ensure an accurate measurement. The same goes for the lab itself. Technicians should take all the precautions necessary for the proper handling and processing of the sample taken to guarantee that the best possible treatment strategy is attainable, which is always based on the data they collect and provide.

 

Reference:

(1, 5, 7) The Best Practice Advocacy Centre. Best Tests. 2013. Factors that can affect laboratory investigations.

https://bpac.org.nz/bt/2015/april/laboratory-investigations.aspx

(3)        Scientific American. What Everyone Should Know about Lab Tests. 2016

https://blogs.scientificamerican.com/guest-blog/what-everyone-should-know-about-lab-tests/

(2, 4)  The American Association for Clinical Chemistry (AACC). Lab Tests Online organization. How reliable is Laboratory Testing? 2015.  

https://labtestsonline.org/articles/laboratory-test-reliability

(6)        The American Society for Clinical Pathology. Laboratory Medicine.

https://academic.oup.com/labmed/article/43/2/41/2505001

(8, 9)    National Academies Organization. The National Academies of Science, Engineering, and Medicine.

http://www.nationalacademies.org/hmd/~/media/Files/Report%20Files/2015/Improving-Diagnosis/DiagnosticError_Toolkit.pdf

(10)      As Lab Testing Matters Organization. Do No Harm: Diagnostic Errors and the Lab 2017.

http://www.labtestingmatters.org/do-no-harm-diagnostic-errors-and-the-lab/

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