A Comprehensive List of Investigations

Kajanan Nithiyananthan -

Sometimes you just want to see a list of all the different investigations that exist so that you can remember that one key test that you're forgetting to include.

Here's that list (unfortunately, it's not fully complete yet).

Non-blood

  • ECG (electrocardiogram)
  • Spiro (spirometry)
  • Urine
    • Urine dip (urine dipstick / urinalysis)
    • Urine MCS (urine microscopy, culture, sentivities)
    • Urine osmolality
  • Stool
    • Stool MCS
    • Stool OCP (stool ova, cysts, parasites)
    • Clostridioides difficile
      • GDH antigen test (glutamate dehydrogenase antigen test) + C. difficile toxin A & B [these must be performed together]
      • C. difficile NAAT (nucleic acid amplification testing)
  • Urea breath test
    • → to test for H. pylori colonisation in stomach

Blood Tests

  • FBC (full blood count) / CBE (complete blood examination)
  • Blood film / blood smear
  • EUC (electrolytes, urea, creatinine)
  • LFTs (liver function tests)
  • Coagulation studies (coags), D-dimer, fibrinogen
  • CRP
  • ESR (erythrocyte sedimentation rate)
  • Procalcitonin
    • → used to assess if patient has a bacterial infection
  • Blood gases (note: these don't need to be sent to the lab)
    • VBG (venous blood gas)
    • ABG (arterial blood gas)
  • Nutrition, including vitamins & minerals
    • Vit D
    • Vit B12, folate
    • Iron studies (iron, transferrin / total iron binding capacity [TIBC], ferritin, transferrin saturation)
      • sTFR (soluble transferrin receptor)
    • Lipid studies
    • RPG (random plasma glucose)
    • FPG (fasting plasma glucose)
    • HbA1c (glycated haemoglobin)
  • Hormones
    • TSH
    • Thyroid function tests (TSH, fT4, fT3)
    • Cortisol
    • Prolactin
    • LH, FSH
    • PTH/PTHrP
  • Drug levels
    • Vanc level (vancomycin level)
    • Dig level (digoxin level)
  • Serology
    • Hep B, Hep C, HIV
  • Troponin
  • BNP (brain natriuretic peptide)
    • → used to assess if patient has heart failure
  • Blood cultures (blood microscopy, culture, sensitivities)

Imaging

  • X-rays
    • CXR (chest x-ray)
    • AXR (abdominal x-ray)
  • Ultrasound
    • USS KUB (ultrasound kidneys, ureter, bladder)
    • Duplex ultrasound
      • → for assessing for DVTs
    • Echo (echocardiogram)
  • CT scans
    • CTB non-con (CT brain non-contrast)
    • CTB con (CT brain contrast)
    • CTPA (CT pulmonary angiogram)
  • Nuclear imaging
    • V/Q scan (pulmonary ventilation/perfusion scan)
      • → for assessing for PEs
  • MRI
  • PET

Resources

  1. UpToDate: A laboratory approach to diagnosis of Clostridioides difficile