From the Guidelines
For a patient presenting with nausea and vomiting, initial laboratory tests should include a comprehensive metabolic panel (CMP), complete blood count (CBC), urinalysis, and pregnancy test for women of childbearing age. The CMP evaluates electrolytes (sodium, potassium, chloride, bicarbonate) to assess for dehydration and metabolic alkalosis from prolonged vomiting, as well as kidney and liver function 1. A CBC can identify infection, anemia, or other hematologic abnormalities that might contribute to symptoms. Urinalysis helps assess hydration status and can detect ketones suggesting starvation ketosis.
Additional targeted tests may include:
- Lipase and amylase to evaluate for pancreatitis
- Thyroid function tests if thyroid disease is suspected
- Toxicology screens when appropriate If the patient has concerning neurological symptoms, a head CT might be warranted to rule out increased intracranial pressure 1. For persistent or severe cases, further testing could include abdominal imaging studies or upper endoscopy. These tests help identify the underlying cause of nausea and vomiting, which is essential for appropriate management and treatment. The most recent and highest quality study 1 supports the use of these initial laboratory tests to guide further management.
It's also important to consider the differential diagnosis of nausea and vomiting, which includes a broad range of pathologic and physiologic conditions affecting the gastrointestinal tract, the central nervous system, and endocrine/metabolic functions 1. A careful history and physical examination are crucial in assessing the patient and identifying any signs that may point to the cause of the symptoms.
From the Research
Laboratory Tests for Nausea and Vomiting
The following laboratory tests may be checked in a patient presenting with nausea and vomiting:
- Urinalysis 2
- Urine pregnancy testing 2
- Complete blood count (CBC) 2, 3
- Comprehensive metabolic panel 2, 4
- Amylase and lipase levels 2
- Thyroid-stimulating hormone level 2
- Stool studies with cultures 2
Additional Tests
Depending on the suspected diagnosis, additional tests may be ordered, such as:
- Imaging studies, including abdominal radiography, ultrasonography, and computed tomography 2
- Computed tomography of the head if an acute intracranial process is suspected 2
- Esophagogastroduodenoscopy for patients with risk factors for gastric malignancies or alarm symptoms 2
- Gastric emptying study if gastroparesis is suspected 2