Diagnostic ToolsHB62010

Signs

•Subjective observations (things that are observed or measured by another person)

•Examples:▫Rash▫Blood in urine▫Vomiting▫Temperature

Symptoms

•Objective observations (things that a patient reports)

•Examples:▫Headache▫Stomach ache▫Tiredness/fatigue

Identify the following as signs or symptoms:

•Nausea•High blood pressure (hypertension)•Broken leg identified on X-ray•Blisters on foot•Painful area of foot•Deformed kidney identified by ultrasound

•Sore back•Mental confusion

Blood tests

•Proportions of various blood cells•Morphology (shape) of blood cells•Biochemistry

▫Glucose▫Calcium, sodium, potassium▫Liver enzymes▫Hormone levels▫Blood urea nitrogen (BUN)

Urine tests

•Red blood cells•White blood cells•Bacteria•Protein•Crystals•Glucose, ketones

Other non-invasive tests

•Listening to chest sounds•Heart rate, blood pressure•Visual observations•Peak flow meter•Breath test for Helicobacter pyloris•Reflexes

Endoscopy•A tube containing optic fibres is passed into the body▫Some fibres transmit light

▫Some fibres transmit an image back to a monitor

▫Surgical tools can be used to take biopsies or carry out surgical procedures

•Arthroscopy•Bronchoscopy•Gastroscopy- e.g. pill cam•Colonoscopy•Laparoscopy

X-rays

•X-rays are produced by some radioactive materials

•High energy beams are passed through the body & strike a photographic film

•Gives limited information on soft tissues

•Too many X-rays can involve high exposures to radiation

CT/CAT scans•Computed axial tomography

•Multiple high quality X-ray images are taken, & a computer builds them up into a 3-dimensional image

•Contrast dyes improve the image quality

The negative side of CT scans

•Chest X-ray 0.1 mSv

•Head CT 1.5 mSv

•Screening mammography 3 mSv

•Abdomen CT 5.3 mSv

•Chest CT 5.8 mSv

•Chest, abdomen and pelvis CT 9.9 mSv

MRI•Magnetic resonance imaging involves the use of powerful magnets

•These magnets excite electrons in cells, & a detector is used to take this information & build up an image from this

•Multiple scans can be used to build up a 3-dimensional image

Functional MRI

•Areas of the brain ‘light up’ when carrying out certain processes

•Can identify regions of the brain involved in emotions etc.

Ultrasound

•High frequency soundwaves are sent into the body

•The soundwaves bounce off structures (like radar/sonar), & a detector builds up an image

•Often used for pre-natal examinations of a developing baby

ComparisonX-ray CT scan MRI Ultrasound

Biopsies

•A small piece of tissue is excised (cut out) and examined under the microscope