Lab test interpretation is a complex clinical skills, requiring family nurse practitioners (FNPs) to think critically and analyze trends. Mistakes in lab test interpretation can happen easily, especially when younger nurse practitioners are first starting their career, or when providers are overworked or short on time. In this article, we’ll dive into some common test interpretation mistakes and the techniques nurse practitioners can use to avoid these errors.
Missing trends in lab tests
One of the most important aspects of lab interpretation is pattern recognition, and it’s easy to miss trends during this process. While a patient’s test result may remain within the normal range, consistent movement in one direction could signal that something is going wrong. It is important to recognize progression in lab test results before the numbers fall out of normal range, so you can catch and treat the problem earlier.
Here’s an example of the importance of trend recognition: As an FNP, you are likely on high alert regarding hyperglycemia and diabetes, which are common health conditions within the United States. Monitoring a patient’s blood glucose levels via an A1C test can help catch prediabetes before it becomes more serious. While a patient may continue to test at normal levels, under 5.7 percent, a provider should know if the value is increasing over time. This information can help nurse practitioners better counsel patients on diet and lifestyle changes needed to delay or avoid the development of type II diabetes.
How can nurse practitioners prevent trend oversights in test interpretation?
Depending on your electronic health records system, it can be tedious or even challenging to view a patient’s previous test results. It can also be hard to properly compare test results while taking into account other factors like the time of day, the patient’s diet, fasting, etc. This step takes extra work that you may not have time for, but it is essential to getting the test interpretation correct. To avoid missing trends in important lab tests, nurse practitioners can keep additional notes in a patient’s file about the test results that are being monitored, how frequently they need to be rechecked, and what to look out for. This serves as a cheat sheet for you to reference in future visits in order to keep an eye out for dangerous trends.
Overinterpreting minor variations
Recognizing trends can also prevent overdiagnosis. Reference ranges exist specifically because no two people are exactly alike. Slight variations in test results between individuals—or for one individual over time—can be normal. Failing to keep this in mind can result in nurse practitioners overdiagnosing, ordering unnecessary follow-up tests, and causing patients needless stress.
How can nurse practitioners correctly identify normal variations?
Nurse Practitioners can avoid overinterpretation of lab test results by reviewing a patient’s results over time. Certain tests have natural variations. For example, lipid panel results will vary depending on the patient’s recent diet and exercise routine. Evaluating these tests in context to the patient’s previous results will help you identify worrisome trends or recognize normal variation within results.
That said, nurse practitioners must pay attention to critical levels. While some level of variation is acceptable and even expected, certain test results can vary too much. Considering cholesterol again, a patient with hypertriglyceridemia is at risk of acute pancreatitis. A triglyceride level of 1000 mg/dL is generally considered the critical value for taking action to prevent life-threatening acute pancreatitis.
Related: Online Course on Laboratory Data Interpretation
Analyzing lab results out of context
It’s also common for nurse practitioners to fail in seeing the larger picture. Considering the clinical context of the lab test is essential to properly diagnose patients and monitor chronic health conditions.
Reference ranges can be helpful, but they are just that: references. If a patient is experiencing certain symptoms, a slightly abnormal test result could be the evidence you are looking for, even if it isn’t outside of the reference range. On the other hand, patients with chronic conditions can often have certain test results outside of the reference range, but for these patients, it is normal.
How can nurse practitioners learn to consider the clinical context of lab test results?
Nurse practitioners can learn to place test results within the clinical context by remembering why the test was ordered in the first place and working to answer that question. Before looking at the test result, remember your patient’s unique data points: their age, gender, medications, personal health history, family background, job, living situation, lifestyle, and more.
Then, keep this in mind as you scroll through the patient’s lab results. By viewing the whole of the clinical context, you can better gauge the importance of a slight variation in a test result and make a more informed decision as to the best next step.
Falling victim to confirmation bias
Confirmation bias is a mistake prevalent across many areas of medicine. It occurs when a medical provider has a theory about a diagnosis and subconsciously focuses their attention on answers that confirm their hypothesis. This can happen in lab result interpretation, diagnostic imaging interpretation, or even patient assessment. Additionally, it can be hard for newer nurse practitioners to recognize and fight against this tendency, as it is a skill that takes time to develop.
How can nurse practitioners recognize and prevent confirmation bias in lab test interpretation?
When confirmation bias strikes in lab test interpretation, nurse practitioners may unintentionally give too much weight to one lab result that confirms their suspicions and overlook other test results that lead to a different diagnosis. To prevent confirmation bias, nurse practitioners should go through lab test results slowly and chronologically and give as much review time to every lab result. Once you’ve reviewed all the results, you can go back and reconsider the ones that stick out.
Ordering the wrong lab tests
Finally, test ordering is an important part of test interpretation that has its own series of potential errors. Ordering the wrong tests is costly and potentially invasive or inconvenient for patients. Ordering too few tests may result in overreliance on one test result for diagnosis.
Additionally, nurse practitioners need to counsel patients on the tests being ordered and any instructions for them, like whether patients need to fast beforehand. If patients fail to prepare properly before a blood draw, the test results will be inaccurate and need to be redone.
How can nurse practitioners feel confident in lab test ordering?
When reviewing lab results, nurse practitioners should confirm with patients that they adhered to the test prep instructions. They should also consider other potential interferences that could lead to an inaccurate test result. To confirm a diagnosis, an NP might have to order follow-up tests, re-order the same test, or select other tests that can help you rule out other answers, as in a differential diagnosis. Younger nurse practitioners should not hesitate to confer with mentors, supervisors, and specialists to ensure proper test ordering and result interpretation.
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