Family Nurse Practitioners Using Differential Diagnoses to Identify and Treat Medical Conditions

Articles | Family Nurse Practitioner | Master of Science in Nursing | MSN Post-Master's Certificates

As primary care providers, family nurse practitioners (FNPs) must utilize patient medical history, physical assessments and clinical reasoning skills to establish differential diagnoses and develop treatment care plans for the best patient outcomes. Learning how to construct these differential diagnoses — or using the problem-solving process to distinguish similarly presenting diseases and medical conditions — is a vital component of FNP practice because it incorporates critical thinking, information gathering and decision-making.

Family nurse practitioner performing an assessment on a patient

FNPs provide care by assessing, diagnosing and treating medical conditions and diseases, with a focus on advancing health goals and preventive care. They depend on patient input, physical exams, diagnostic testing and clinical reasoning to determine an accurate diagnosis, particularly in patients with comorbid conditions.

Establishing a differential diagnosis can be challenging for even the most experienced FNPs. However, scientific studies have found FNPs who master clinical reasoning skills provide care equal to a physician.

Clinical decision-making in advanced practice nursing is a continuous, purposeful, theory- and knowledge-based process of assessment, analysis, strategic planning and intentional follow up, according to the authors of “Advanced Practice Nursing, Fifth Edition: Core Concepts for Professional Role Development.”

“It is both a cognitive and affective problem-solving activity for defining patient problems and selecting appropriate management,” the authors said.

For FNP students, the skill comes with extensive education and practice, including coursework that covers clinical judgment, problem-solving and hypothesis generation. At Duquesne University, students studying to become nurse practitioners research the theoretical frameworks behind developing a differential diagnosis and the link to patient resilience, vulnerability and stability.

Nurse Practitioners Using Clinical Reasoning for a Differential Diagnosis

The National Academies of Sciences, Engineering, and Medicine described clinical reasoning as “the clinician’s quintessential competency.” The National Academies said clinical reasoning is based on a process that integrates both analytical and non-analytical decision-making, called the dual-process theory. The theory contains two components:

  • The non-analytical model, also called fast system 1, involves automatic recognition patterns that depend on working memory. An example of fast system 1 is the ability to diagnose Lyme disease by the bull’s-eye rash pattern.
  • The analytical model, called slow system 2, involves a concerted process guided by critical thinking that depends on hypothetical reasoning. For this model, individuals must generate mental representations of what should happen in particular scenarios. For example, if a diabetic is prescribed the appropriate medication, sugar levels should improve.

Experts say errors in judgment and diagnoses are due to faulty reasoning, ethical violations, cognitive biases and conflicts of interest that interfere with decision-making.

Steps to Establishing a Differential Diagnosis

In general, a differential diagnosis is established through a process of elimination and identifying the presence of a disease or condition. FNPs make clinical decisions and diagnoses using a theory- and knowledge-based process of assessments.

To establish an accurate diagnosis, clinicians use a stepwise progression to develop a working differential diagnosis, as follows:

  1. Identify chief complaint

To determine the chief complaint, providers should ask a series of open-ended questions and create a general history of the symptoms. The symptom-analysis questions help establish the onset, location, duration, character, associated symptoms, trigger factors, alleviating factors and impact on daily life. Clinicians should also ask directed questions that could clarify or provide additional information to narrow the diagnostic possibilities.

  1. Review patient’s general health

By gathering or confirming general health information, clinicians may be able to uncover new facts that could lead to a diagnosis. Clinicians should review past medical, familial and social history to determine disease risk factors, occupational exposure to harmful substances or the presence of drug or alcohol abuse.

  1. Perform physical exam

Clinicians should perform a focused physical examination that is directed to the chief complaint. In addition, clinicians should take into account the patient’s facial expressions, mood, hygiene, stress level, skin color/condition and breathing patterns for information that can be vital to an accurate diagnosis.

  1. Order diagnostic testing

In some cases, diagnostic testing must be ordered to make a correct diagnosis. The process should begin with basic testing and continue to advance testing if needed.

  1. Determine and write a differential diagnosis

In determining the likely diagnosis, it is important to keep an open mind to all possibilities. Any premature decision may result in a diagnostic error.

The authors of “Differential Diagnosis for the Advanced Practice Nurse” said novice clinicians face challenges when making a differential diagnosis due to a lack of experience and knowledge.

“However, it serves to stimulate exploration and learning, and with experience and guidance, knowledge grows. The novice will find that a solid reference enables him or her to master the task of differential diagnosis as his or her clinical experience matures,” the authors stated.

After a differential diagnosis is created, clinicians should be able to demonstrate why it is accurate for the case and keep an open mind about other possibilities. Treatment plans can include pharmacological agents, patient education and follow-ups.

Provider Characteristics That Impact a Differential Diagnosis

For clinicians, there are several characteristics that can impact the outcome of a differential diagnosis. These are based on individual circumstances and include the following:

  • Clinician’s personality

Personal experiences, attitudes and gender influences can impact clinical reasoning that leads to differential diagnoses. Arrogance may make a clinician overly confident. Agreeableness may allow a clinician to explore a variety of diagnosis options.

  • Clinician’s physical state

Fatigue, stress and sleep deprivation can impact reasoning and a willingness to be open to a range of clinical possibilities.

  • Clinician’s age

Older, more experienced clinicians may be able to better utilize diagnoses that involve automatic recognition due to well-developed understanding and mental models of diseases and conditions.

  • Clinician’s experience

Novice and experienced providers make different decisions based on a variety of factors. For example, one study shows experienced nurses gather more cues and hints toward a differential diagnosis than their novice counterparts.

For all advanced practice registered nurses (APRNs), including FNPs, a key to developing a differential diagnosis is having a greater understanding of the process of clinical problem solving. At Duquesne University, students enrolled in the online Master of Science in Nursing (MSN) FNP program learn how developing clinical reasoning is vital to successful practice.

About Duquesne University’s Online MSN Family (Individual Across the Lifespan) Nurse Practitioner

Duquesne University’s online FNP program prepares APRNs for a career working alongside physicians and in private practice. The coursework is presented entirely online so nurses can maintain their careers and personal lives while pursuing their education goals simultaneously.

The online MSN FNP program prepares APRNs for the American Academy of Nurse Practitioners Certification Board (AANPCP) and American Nurses Credentialing Center (ANCC) Family Nurse Practitioner certification examinations. For more information, contact Duquesne University today.