Urine preservatives - specimen collection, Mechanical Engineering

Urine preservatives - Specimen collection:

Urine preservatives: preservatives have different roles but are usually added to reduce bacterial action or chemical decomposition or to solubilize constituents that might otherwise precipitate out of solution. Another application is to decrease atmospheric oxidation of unstable compounds. Some specimens should have no preservative added because of possibility of interference with analytical methods. One of the most satisfactory forms of preservation of urine specimens is refrigeration immediately after collection. Urine preservative tablets contain many compounds that act on decreasing the pH of the urine or releasing of formaldehyde. Formalin is also used, but in large amounts it precipitate urea and inhibit certain reactions.

Acidification below pH 3 is widely used to preserve 24 hr urine specimens and is particularly useful for specimens for calcium, steroid, vanillylmandelic acid (VMA) determination (10 ml of HCl, 6 mol/L, per 24 hr excretion).

Sulfamic acid (10 g/L urine) is also used to educe pH. Boric acid ( 5 mg/30 ml) has been also used During acidification, precipitation of urates will occur, thereby rendering a specimen unsuitable for measurement of uric acid. Although thymol and chloroform were widely used in the past to preserve specimens for chemical and microscopic examination. Toluene is the only organic solvent that is still in use as a preservative. A mild base, such as sodium bicarbonate or small amount of NaOH, is used to preserve porphyrins, urobilinogen, and uric acid. When timed collection is complete, the specimen should be delivered without delay to the laboratory.

 

Posted Date: 10/15/2012 5:34:26 AM | Location : United States







Related Discussions:- Urine preservatives - specimen collection, Assignment Help, Ask Question on Urine preservatives - specimen collection, Get Answer, Expert's Help, Urine preservatives - specimen collection Discussions

Write discussion on Urine preservatives - specimen collection
Your posts are moderated
Related Questions
Classification Based on Type of Welding  Fusion welding : These processes involve fusion of the base metal to complete the weld. Fusion welds generally  do  not  require  thea


Illustrate with required expression for dynamically equivalent system. Illustrate in detail about the Balancing of Radial Engines.

question no 2,page no 84 of strenght of materials by G H Ryder

what is the least count of following instrument? vernier caliper micrometer bevel protractor dial

GAS METAL ARC WELDING (GMAW) GMAW is abbreviation for Gas shielded Metal Arc Welding. Here fusion is achieved by an electric arc formed between work piece and process is called

impartance of moulding sand

Connecte d Rod: It is attached to piston at its small end by means of gudgeon pin. The big end bearing is connected to crank pin. It is made up of forged steel.

Chisel: Chisels are used in the combination of hammer to remove metals. A set of chisels is shown in Figure. Figure: Chisel

1. The linkage system below consists of two bars A & B plus 4 linkages. Each linkage has a square cross section. The allowable tensile strength of all members is 200 MPa, the allow