How Effective Is Urine as an Antiseptic?

Urine preservative

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Urine

Urine preservatives. To obtain accurate results after urine collection, correct specimen retention and good storage conditions are key steps in quality control before analysis. The preservation methods of this inspection specimen are generally refrigerated method and chemical preservative method. For regular urine specimens and urine analysis that cannot be performed within 2 hours after specimen collection or the urine composition to be analyzed is unstable, specific chemical preservatives can be added, and stored under refrigeration.

(1) Formaldehyde

Also known as formalin. It has a fixed effect on urine cells and casts. 0.5ml of 40% formaldehyde is added per 100ml of urine. Due to the reducing nature of formaldehyde, it is not suitable for the detection of chemical components such as urine sugar.

(2) Toluene

When the amount of toluene is sufficient, a layer of toluene film can be formed on the surface of the urine specimen to prevent the urine from contacting with the air to achieve an antiseptic effect. 0.5 ml of toluene was added per 100 ml of urine. Commonly used for qualitative or quantitative analysis of chemical components such as urine sugar and urine protein.

(3) Thymol

The addition of thymol to urine samples can not only inhibit the growth of bacteria and play a preservative role, but also can better preserve the formation of urine in the urine. Generally, less than 0.1g of thymol is added to 100ml of urine, which can be used for urine microscopy, especially urine concentrated tuberculosis examination, and preservation of specimens for chemical composition inspection.

(4) concentrated hydrochloric acid

For the quantitative determination of 17-hydroxycorticosteroids, 17-ketosteroids, catecholamines, oxalates, calcium, phosphorus and other urine samples for preservation, 10 ml of concentrated hydrochloric acid is added per liter of urine. Concentrated hydrochloric acid has strong anti-corrosion properties and is easy to volatilize at room temperature, so the container must be resistant to corrosion and pressure. The user must be advised to be careful to avoid burning the skin and clothing. Be sure to collect the first urine before use and add preservatives.

(5) Sodium fluoride

Sodium fluoride can prevent urinary glycolysis and is suitable for the preservation of urine samples for glucose measurement.

(6) Boric acid

It can inhibit bacteria within 24 hours and only interfere with the pH of routine urine screening. It is suitable for preservation of urine specimens for protein and uric acid detection.

(7) Glacial acetic acid

Preservation of urine specimens for aldosterone, catecholamine, and estrogen detection.

"Clinical Laboratory Basics"

"Effect of Preservatives on Quantitative Detection of 24h Urine Protein"