The first observation made about a urine specimen is usually its appearance, which generally refers to the clarity of the specimen.
Cloudy urine signals a possible abnormal constituent, such as white blood cells (WBCs), RBCs, or bacteria. Cloudy urine may also be due to normal urinary components within the bladder, which can be caused by a change in urine pH. Alkaline urine may appear cloudy because of phosphates; acid urine may appear cloudy because of urates.
Observe the clarity of a fresh urine sample by visually examining a well-mixed specimen in front of a light source.
Use common terms to report appearance, including the following: clear, hazy, slightly cloudy, cloudy, turbid, and milky.
Document results. The degree of turbidity should correspond to the amount of material observed under the microscope.
Pathologic urines are often turbid or cloudy; however, normal urine can also appear cloudy.
Urine turbidity may result from UTIs.
Urine may be cloudy because of the presence of RBCs, WBCs, epithelial cells, or bacteria.
After ingestion of food, urates, carbonates, or phosphates may produce cloudiness in normal urine on standing.
Semen or vaginal discharges mixed with urine are common causes of turbidity.
Fecal contamination causes turbidity.
Extraneous contamination (e.g., talcum powder, vaginal creams, radiographic contrast media) can cause turbidity.
“Greasy” cloudiness may be caused by large amounts of fat.
Often, normal urine develops a haze or turbidity after refrigeration or standing at room temperature because of precipitation of crystals of calcium oxalate or uric acid.