Diagnostic Testing

Diagnostic Testing

A diagnostic test is any kind of medical test performed to aid in the diagnosis or detection of disease.

to diagnose diseases to measure the progress or recovery from disease to confirm that a person is free from disease

Types Invasive Minimally-invasive Non-invasive

Diagnostic Testing

Other characteristics of tests include: sensitivity specificity positive predictive value negative predictive value false positive false negative

Test options

Consulting room tests auscultation height and girth blood pressure pulse breath tests reflex tests eye examination ophthalmoscopy hearing test digital rectal examination vaginal exam

Testing options

Requiring laboratory analysis Urine tests Stool tests Hair tests Saliva tests Blood tests Erythrocyte sedimentation

rate (ESR) Complete blood count (CBC) Comprehensive metabolic

panel (CMP) Arterial blood gas (ABG) DNA tests

invasive examinations biopsies lumbar puncture

Requiring microscopy Pap smears

Testing options

Requiring elaborate medical equipment X-rays

barium enema intravenous pyelogram (IVP test)

ultrasound scans electrocardiogram (ECG or EKG) electroencephalogram (EEG) computer aided tomography (CAT) scans positron emission tomography (PET) magnetic resonance imaging (MRI) endoscopy

colonoscopy cystoscopy sigmoidoscopy colposcopy

blood test

X-Ray

“plain films” Bone abnormalities – Fx, dislocation, joint spaces Ectopic bone formation in soft tissue Bone tumors

Arthrogram

X-ray after an injection of a dye Shows the disruption of soft tissue

or loose bodies in the joint Uses a Fluoroscope

Fluoroscopy

Provides immediate projection of X-ray image on screen for viewing

Common for GI tract testing, cardiac catheterization, hip/shoulder injections

Portable x-ray in pros & D-I

Computed Tomography

Thin , fan shaped x-ray beam Cross section view if tissue Many angles Visual image on a computer

Positron Emission Tomography (PET)

Nuclear medicine imaging technique which produces a three-dimensional image of functional processes in the body.

Detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide (tracer)

Bone Scan

IV – radioactive tracer Bony lesions with inflammation will “take-up”

more dye (Bone stress sites)

Magnetic Resonance Imaging

Electromagnets circle the body Field up to 600,000x as strong as earth Magnet aligns hydrogen atom in water molecules. When

turned off, atoms continue to spin, emitting an energy that is detected by the computer.

Hydrogen atoms in different tissues spin at different rates

Ultrasonography

Used to view the location of, alignment of and measure the size of organs/tissue

Measures the reflection or transmission of high-frequency ultrasound waves

Computer calculates the distance from the

sound-reflecting/absorbing surface and creates

a two-dimensional image

Echocardiography

Uses ultrasound to produce image of cardiac structure/function

Can see the valves & dimensions of the 4 chamber

Electroencephalography

EEG Records electrical potentials produced in the brain Changes in brain wave patterns

Electromyography

Graphic recording of muscle contractions & the amt of electrical activity generated in a muscle

EMG Surface or needle electrodes Motor unit potentials can be observed on

a oscilloscope screen or from a graphic

recording (electromyogram)

Arteriography

Catheter is inserted into specific vessel Contrast is injected & radiographs are taken Blockage/Aneurysm

Electrocardiography

ECG/EKG Electrical activity of the heart Impulse formation, conduction, depolarization &

repolarization of the atria & ventricles follows a normal pattern

Nerve Conduction Velocity

Conduction velocity of nerves Apply stimulus to a peripheral nerve and measure

the speed at which the muscle action occurs Nerve compression/nerve fx

Synovial Fluid Analysis

Used to detect the reason for an joint effusion, increase ROM, by decreasing joint effusion

Not commonly used anymore Looked for blood & infections

Serum Testing

CBC Screen for numerous condtions

Anemia, diabetes, infection, monitor kidney function RBC count, hemoglobin levels, hematocrit, WBC count,

platelet count, cholesterol, etc

Urinalysis

UA Specific gravity, pH, ketones, hemoglobin, protein, nitrates,

WBC, drugs, hormones, electrolytes, glucose, RBC Color, odor, volume

Urinalysis - Procedure

Specimen collection Clear, clean container Fresh urine……if longer than 1 hr, put in frig Mid stream urine

Testing procedures Briefly (< 1 sec) dip test strip into urine Draw the edge of the strip along the rim to remove

excess urine Turn strip on its side and tab on a paper towel After appropriate time (1 min), compare strip to side of

container….if Leukocytes (+), reread @ 2 mins

Urinalysis – Testing for

Specific Gravity: Ability of kidneys to concentrate and dilute fluids; hydration levels

pH: Refers to how acidic or alkaline the urine is. Acidic urine is found in cases of diabetes & dehydration. Alkaline urine is a sign of a urinary tract infection or kidney disease

Glucose: Diabetes Hemoglobin: Kidney disease or after intense exercise Protein: Kidney disease Nitrates: Infection Ketones: Eating disorder, fasting Leukocytes: Infection

Urinalysis - Normal

Specific Gravity: 1.016 – 1.022 pH: 5-9…..morning urine Glucosuria……none Proteinuria……up to 30mg/dL Hematuria…….up to 5Ery/uL is okay Leukocytes…...none Ketones……….none Nitrates……….none

Urinalysis

Color: Normal – pale yellow Dark –dehydrated Red/brownish – blood, hemoglobin, myoglobin,

bilirubin Cloudy/milky – infection

Odor: Foul/strong - infection