Investigations 

Overview

Core investigations

• Bedside investigations

  • • • ECG, 

      • Peak flow, 

• Body fluids

  • • • Bloods

      • Urine

      • Faeces

      • Fluid Aspirate

      • Cerebrospinal fluid

      • Saliva

• Imaging

  • • • US

      • XR

      • CT

      • MRI

• Interventions

  • • • Procedures (local anaesthetia)

        • • • • • Lumbar puncture

                • Ascitic tap

                • Needle aspirate

              • Scopes

      • Operations (General anaesthetic)

Simple Bedside

Self defined as investigations done at the bedside that do not require any anaesthetic. I have catagorised them into body fluids and not:

• Body fluids

  • • Bloods

      • • • FBC, U&Es, CRP, LFTs

          • Blood cultures

          • Troponin, d-dimer/ coagulation, lactate, blood sugar

          • Lipase, calcium, magnesium phosphate, B12, folate, HbA1c, cholesterol, CK, BNP, 

          • Rarer tests i.e. autoimmune screen, specialty screens- vasculitis, neurology, gastro

    • Urine

      • • • Urine analysis

          • Urine culture

          • Urine drug screen

    • Faeces

      • • • Culture: c.diff 

          • Faecal calprotectin

          • Q-Fit (looking for blood ?GI cancer)

    • Saliva

      • • • Viral throat swab ?covid ?influenza A, B

• Everything else

  • • ECG

    • Peak flow

Imaging

The four major modalities are US, XR, CT and MRI; although others do exist. 

• USS

  • • Bladder scan

    • Pregnancy AUSS

    • AUSS- gallbladder, appendix in children, ovaries

    • USS lump, e.g. breast or elsewhere

    • Doppler USS ?DVT

• XR

  • • CXR

    • AXR

    • UL or LL XR

• CT

  • • CT-H

    • CTAP

    • CTPA

    • CT-Thorax / CTCAP

    • CT-Full body trauma

    • CT Angiography

      • • Carotid angiography

• MRI

  • • MRCP ?biliary stone disease

    • MRI spine ?cauda equinae

Procedures

The function of intervention is either investigative, therapeutic or both. 

Many interventions have the ability to both diagnose and treat the condition, i.e. endoscopy visualises the lesion and facilitates its removal. 

• Local anaesthetic

  • • Lumbar puncture

    • Ascitic tap

    • Needle aspirate

    • Excision and drainage E+D

• Scopes

  • • Endoscopy, colonoscopy, sigmoidoscopy

    • Endoscopic retrograde pancreatography- ERCP

    • Hysteroscopy

    • Cystoscopy, ureteroscopy

• Specialist intervention: general anaesthetic or specialist knowledge

  • • Biopsy, e.g. cancer

    • Lymph nodes

    • Lung, breast, thyroid, colon, ovarian, prostate etc

    • Bone marrow biopsy

    • Non cancer biopsies

    • Diagnositic operations

    • Diagostic laparotomy for endometriosis

References and Resources

Written in 2025