Urinalysis

Testing urine is known as urinalysis .

It is performed when;

A patient is admitted to hospital.

May be repeated whilst the patient is in hospital again.

And any time it is prescribed.

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Mid stream urine test

The sample should be taken without contamination from the external genitals, and the mid stream urine means that only the middle part of the urine stream is collected. Therefore it is important to clean the external genitalia in both males and females before urinating to prevent contamination. This process is difficult to obtain at times and therefore a clean catch urine may be preferred. (http://www.virtualbloodcentre.com/investigations.asp?

sid=29)

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process

Obtain urine free from contamination.A clean dry container should be used to hold the urine.Follow manufactures instructions.Check the expiry date.Avoid unnecessary exposure to air, light and moisture.Do not transfer agent from their original bottles into others Time test accuratelyIf abnormalities are detected do not discard specimen . Report and document the results immediately.Dispose of all material strips, etc appropriately.Wear goggles throughout the procedure.

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Urinalysis cont…

Urine being tested should be fresh - why do you think this is important?

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Chemical reagent strips

Are used to test urine, and urinalyis provides information about;The condition and function of the urinary system.The presence of pathogenic micro organisms in the urinary tract or urine.The presence of unrelated disorders of the urinary system.The acid base balance of the body. The presence of nutrient materials that are normally transported to the body cells , but which may have been excreted in the urine, eg glucose.

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Chemical reagent strips cont….

The presence of systemic disease which in unrelated to disorders of the urinary system

The acid base balance of the body (chandler 1995,p 258)

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Characteristic normal abnormal Possible cause

Amount in 24 hours (Adult)

1200-1500 Under 1200mls

Decreased fluid intake kidney failure

colour Straw -amber

Dark amber Insufficient fluid intake resulting in concentrated urine

transparent Cloudy dark orange

Infectious processdrugs

Red or darkbrown

Disease causing blood in urine

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characteristics

normal Abnormal Possible cause

odour Faint aromatic Offensive foul smelling

Infection

Presence of glucoseDiabetes mellitus

Foreign substances

nil PusStones or gravel

UTIUrinary calculi

sterility No micro organisms

Micro organisims present

Infection of urinary tract

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characteristic normal abnormal Possible cause

ph 4.5 to 8 Under 4.5 over 8

Uncontrolled diabetes, starvation, dehydration

Specific gravity

1010 to 1025

Under 1010

Diabetes insipidus. Kidney disease, over hydration

glucose Not present

present Diabetes mellitus

Ketone bodies Not present

present Diabetic coma StarvationProlonged vomiting

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Assessement of urine

Involves measuring the volume.

Comparing output to input.

Inspecting colour, clarity, odour.

Testing the urine for specific gravity, glucose, ketone bodies, blood, and pH.

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Specific gravity

Is the weight or degree of concentration of a substance compared with that of an equal volume of another, such as pure distilled water taken as a standard.

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Limitations of urinalysis

Many of the dipstick results aren't completely accurate, and sometimes gives you positive results that aren't true. The test relies on correct collection of sample by the patient, and if this is not done properly the results may be inaccurate Many of the abnormalities seen with urinalysis can be found in normal people

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