Citizen Science/Open Spectrophotometer Project/Documentation/Urine Analysis

Generalities

Urine is a transparent aqueous solution that can range from colorless to amber but is usually a pale yellow.
Urine contains a range of substances that vary with what is introduced into the body. Aside from water, urine contains an assortment of inorganic salts and organic compounds, including proteins, hormones, and a wide range of metabolites.
Usually odorless, urine can be pungent after the consumption of certain foods (e.g asparagus)
Turbid urine may be a symptom of a bacterial infection, but can also be due to crystallization of salts such as calcium phosphate..
The pH of urine is close to neutral (7) but can normally vary between 4.5 and 8. Strongly acidic or alkaline urine may be symptomatic of disease

The simplest and oldest form of analysis consists of recording the color and appearance of the urine specimen is recorded.
- Usual colors are colorless, straw, yellow, amber; less commonly pink, red, brown.
- Usual appearances (opacity) are clear or hazy; less commonly turbid, cloudy and opaque, unless the specimen has remained at room or refrigerated temperatures.

The Urine Color-Code
- Clear- indicates over-hydration, which is usually considered much healthier than dehydration.
- Yellowing/light Orange may be caused by removal of excess B vitamins from the bloodstream.
- Certain medications such as rifampin and pyridium can cause orange urine.
- Bloody urine is termed hematuria, potentially a sign of a bladder infection.
- Dark orange to brown urine can be a symptom of jaundice or Gilbert's syndrome.
- Black or dark-colored urine is referred to as melanuria and may be caused by a melanoma.
- Reddish or brown urine may be caused by porphyria.
- Fluorescent Yellow / Greenish urine may be caused by dietary supplemental vitamins, especially the B vitamins.
- Dark yellow urine is usually indicative of dehydration.

Routine uri-nalysis is composed of two examinations:
- Chemical tests for abnormal chemical constituents
- Microscopic exam for abnormal insoluble constituents

Chemical Exam
- The common chemical testing of urine utilizes commercial disposable test strips. Bayer's Multistix 10 SG test strips test for Glucose, Bilirubin, Ketone, Specific Gravity, Blood, pH, Protein, Urobilinogen, Nitrite, and Leukocyte Esterase.
- A fresh urine specimen is collected in a clean, dry container. A Multistix strip is briefly immersed in the urine specimen, covering all reagent areas.
- The result of this testing is regarded as semiquantitative.

Microscopic Exam
- In many laboratories it is a standard practice to exclude the microscopic exam if all chemical testing yields negative or normal results.
- In the urinalysis microscopic exam one looks for formed cellular elements, casts, bacteria, yeast, parasites and crystals in centrifuged urine sediment.

General Remark: This section is very short as the chemical and microscopic exams are not the kind of analysis we are after