Step 3: Work-up

Basic tests

Basic tests are directed by medications, history, and physical exam.

Basic tests should include

  • Point-of-care glucose – for hypoglycemia, hyperglycemia
  • EKG – for arrhythmia, ischemia
  • CBC – for leukocytosis, anemia
  • Basic metabolic panel – for renal failure, dehydration, electrolyte abnormalities, particularly hyponatremia, uremia, hyperkalemia/hypokalemia, hypercalcemia/hypocalcemia

Focused Tests

More focused tests can be driven by symptoms or exam findings.

Focused tests may include:

  • Chest x-ray – chest pain, dyspnea, fever, pulmonary edema
  • VBG/ABG – sepsis, hypercarbia, hypoxia
  • Viral respiratory assays or influenza – fevers, myalgias, respiratory symptoms, depending on time of year and prevalence
  • Cardiac enzymes – chest pain, abdominal pain, back pain, abnormal EKG
  • Urinalysis and urine culture – fever, dysuria, hematuria, urgency, frequency, concern for UTI
  • Liver function tests, ammonia, or lipase – abdominal pain, fever, drug toxicity, concern for biliary disease, hepatitis, may also need an abdominal ultrasound
  • Blood cultures – fever, leukocytosis, evidence of infection
  • Abdominal CT – abdominal distention, pain, tenderness, concern for obstruction, appendicitis, or diverticulitis
  • RUQ ultrasound – for RUQ pain, elevated LFTs or lipase to evaluate for cholelithiasis, choledocholithiasis, cholecystitis
  • Urine drug screen, salicylate or acetaminophen levels – for drug use or overdose, or other lab findings, concern for an acute or chronic overdose
  • Blood alcohol level – concern for alcohol abuse
  • Head CT – if decreased level of consciousness without other explanation, signs of head trauma, focal neurologic deficits, severe headaches, concern for stroke or hemorrhage
  • Lumbar puncture – fever, headache, nuchal rigidity, fever of unknown origin, concern for meningitis
  • EEG – concern for occult seizures or nonconvulsive status epilepticus


Lai MM et al. Intern Med J. 2012;42(4):422–427


ABG, arterial blood gas

CBC, complete blood count

CT, computed tomography

EEG, electroencephalography

EKG, electrocardiography

LFTs, liver function tests

RUQ, right upper quadrant (abdomen)

UTI, urinary tract infection

VBG, venous blood gas