View source for Urinalysis/chemical

Commonly, urine is qualitatively measured for '''protein''', '''[[glucose]]''', '''[[hemoglobin]]''', '''[[ketone bodies]]''' and '''[[bile dyes]]'''. These components are usually found in the urine of healthy persons, but in such small quantities that they cannot be demonstrated by conventional tests. Under various pathological conditions, their concentration in the urine increases.

=== [[Wet urine chemistry|Tube reactions]] ===


{{:Chemické vyšetření moči mokrou cestou}}

=== Test (diagnostic) strips ===
The detection of pathological urine components at the bedside or in the line of first contact with the patient is possible by means of test strips. 

Test strips consist of a plastic carrier on which one or more indication zones are fixed. They are produced by aspirating a liquid analytical reagent into a suitable material (e.g. special filter paper) and gently drying it. 

Diagnostic strips are available as '''mono-functional''', '''poly-functional''' or '''special examination''' strips.

'''Monofunctional''' strips contain basic indication zones for the semi-quantitative determination of a substance in urine. '''Polyfunctional''' strips consist of several indication zones, allowing the examination of several biochemical parameters at the same time. They are intended for cases where it is necessary to obtain as much information as possible about the patient's health status, e.g. during various screening events. In addition to monofunctional and polyfunctional strips, there are ''special test'' strips, which include combinations of two or more indication zones that are selected for the investigation of a specific disease, e.g. diabetes mellitus screening strips include a zone for the determination of glucose, ketone bodies, protein and pH.

With the help of test strips, the following parameters can be determined in the urine:
:* [[Urinalysis/chemical#protein|protein]];
:* [[Urinalysis/haemic#glucose|glucose]];
:* [[Urinalysis/chemical#ketolates|ketolates]];
:* [[Urinalysis/chemical#bilirubin|bilirubin]];
:* [[Urinalysis/chemical#urobilinogen|urobilinogen]];
:* [[Urinalysis/chemical#hemoglobin|hemoglobin, erythrocytes]];
:* [[Urinalysis/chemical#ascorbic acid|ascorbic acid]];
:* [[Urinalysis/chemical#leukocytes|leukocytes]];
:* [[Urinalysis/chemical#nitrites|nitrites]];
:* [[Urinalysis/chemical#pH|pH]];
:* [[Urinalysis/chemical#density|density]].

=== Principles of determination of individual parameters ===

==== [[Determination of protein in urine|Protein]] ====
{{Edit article|Determination of protein in urine}}

{{:Stanovení bílkoviny v moči}}

==== [[Determination of haemoglobin in urine|Hemoglobin]] ====
{{Edit article|Urinary haemoglobin determination}}
{{:Determination of hemoglobin in urine}}

==== [[Determination of glucose in urine|Glucose]] ====
{{Edit article|Urinary glucose determination}}
{{:Determination of glucose in urine}}

Glucosuria is most often accompanied by a rise in glucose above the so-called '''renal glucose threshold''' (around 10&nbsp;mmol/l). Glucose, which is normally filtered through the glomerular membrane, is in such high concentration in the primitive urine that it is not enough to be resorbed in the tubules and enters the final urine. Glucosuria with normal glycaemia is indicative of a defect in tubular transport mechanisms - we speak of '''renal glucosuria'''.

==== [[Urinary ketone bodies/status|Urinary ketone bodies]] ====
{{Edit article|Urinary droplets/status}}
{{:Urinary ketone bodies/determination}}

''See also [[Ketone bodies in urine]].''

==== [[Determination of bilirubin in urine|Bilirubin]] ====
{{Edit article|Determination of bilirubin in urine}}
{{:Determination of bilirubin in urine}}

==== [[Determination of urobilinogen in urine|Urobilinogen]] ====
{{Edit article|Determination of urobilinogen in urine}}
{{:Determination of urobilinogen in urine}}

==== [[Determination of leukocytes in urine|Leukocytes]] ====
{{Edit article|Determination of leukocytes in urine}}

{{:Stanovení leukocytů v moči}}
==== [[Determination of nitrite in urine|Nitrite]] ====
{{Edit article|Urinary Nitrite Determination}}

{{:Stanovení dusitanů v moči}}
==== [[Determination of ascorbate in urine|Ascorbic acid]] ====
{{Edit article|Urinary Ascorbate Determination}}

{{:Stanovení askorbátu v moči}}
==== [[Urine pH Determination|pH]] ====
{{Edit article|Urinary pH Determination}}

{{:Stanovení pH moči}}

==== [[Relative Urine Density (Determined by Diagnostic Strips)|Density]] ====
{{Edit article|Relative urine density (determined by diagnostic strips)}}

{{:Relativní hustota moči (stanovení diagnostickými proužky)}}

Urinary density is estimated indirectly by the concentration of cations using diagnostic strips. The indicator zone of the strip contains a suitable polyelectrolyte as an ion exchanger and the acid-base indicator bromthymol blue. The principle of diagnostic strips is based on the exchange of cations from urine, especially Na+, K+, NH4+, for H+ ions of the polyelectrolyte in the indication zone. The released H+ acidifies the weakly buffered acid-base indicator, which is in alkaline form. Acidification is accompanied by a change in colour to bromothymol blue. The disadvantage is that the diagnostic strip test does not take into account substances of a non-electrolyte nature such as [[wikiskripta:Glukóza|glucose]], proteins, [[wikiskripta:Močovina|urea]], [[wikiskripta:Kreatinin|creatinine]] and some others.

=== Diagnostic strip test procedure ===
Remove only as many strips from the tube as you will need immediately. Immediately seal the tube with the remaining strips to protect the unused strips from moisture. Do not touch the indicator zone of the strips with your hands. Store the strips only in their original packaging and well sealed with a bag of desiccant, in a dark, dry place at a temperature of +2 to +30&nbsp;°C.

Dip the strip briefly into the urine for 1-2 s so that all zones are wetted. Then remove the strip and remove the excess urine by wiping the edge of the strip on the rim of the container. Then place it in a horizontal position to prevent mixing of reagents from the individual reagent plates. After the prescribed reaction time, usually 60 s and 120 s for leucocytes, evaluate.

The assessment of the staining of the reaction zones of the diagnostic strips is carried out:
* '''subjective comparison''' of the resulting colour with the colour scale on the label of the tube in which the strips are stored;
* '''objectively'''' by '''[[spectrophotometer#reflection photometry|reflection photometers]]''', which measure the intensity of light of the appropriate wavelength reflected from the reaction field.
=== Overview of urine testing with diagnostic strips ===
{| class=wikitable
 |+ Overview of methods for the detection of pathological urinary components using diagnostic strips
 ! Analysis !! Principle !! False positives!! False negative results
 |-
 | '''Protein''' || Acid-base indicator protein error
 | Alkaline pH, contamination of the sampling vessel with disinfectants based on quaternary ammonium salts, menstruation (do not test 3 days before and after), hemoglobinuria, mysoglobinuria
 | Globulins and immunoglobulin light chains are difficult to detect
 |-
 | '''Hemoglobine''' || Oxidation of chromogen by hydrogen peroxide by hemoglobin pseudoperoxidase activity
 | Microbial peroxidases, contamination of vessels with oxidative cleaning agents
 | High concentration of nitrite, vitamin C
 |-
 | '''Glucose''' || Glucose oxidase reaction coupled with peroxidase reaction
 | Contamination of vessels with oxidative cleaning agents
 | Vitamin C, other reducing agents (gentisic acid, DOPA), urinary infection
 |-
 | '''Ketone bodies''' || Reaction of acetoacetic acid and acetone with nitrpruside in alkaline media
 | Substances with free sulfhydryl groups (e.g. [[captopril]]). Some phenolphthalein- and sulfophthalein-based substances (laxatives and diagnostics) give similar colouration in alkaline environments. Phenylpyruvic acid.
 | &beta;-hydroxybutyrate does not react
 |-
 | '''Bilirubin''' || Azocopulation reaction
 | Substances that have a similar coloration in acidic environments, nitrogen metabolites of bacteria in some urinary infections
 | High nitrite content, light exposure, ascorbic acid
 |-
 | '''Urobilinogen''''' || Azocopulation reaction
 | Substances that have a similar coloration in acidic environments, nitrogen metabolites of bacteria in some urinary infections
 | Formaldehyde, light exposure, old urine, ascorbic acid
 |-
 | '''Nitrite''' || Griess reaction - diazotization of sulfanilamide by nitrite and subsequent azo copulation
 | Bacterial contamination
 | Dietary nitrate deficiency, Gram-positive bacteria, large diuresis, vitamin C
 |-
 | '''Leukocytes''' || Esterase activity of granulocytes and macrophages
 | Formaldehyde, alkaline pH, high urine density
 | Vitamin C, certain medications
 |-
 | '''pH''' || Mixture of acid-base indicators
 | Formaldehyde (apparently lower pH), old urine (alkaline pH)
 |
 |-
 | '''Density''' || Ion exchange of urine cations for H+, determination of pH with acid-base indicator
 | Alkaline pH shifts results to lower values
 |
|}

== Links ==
=== References ===
<references />
=== External links ===
* {{Cite
| type = web
| surname1 = Dastych
| name1 = Milan
| surname2 = Winkler
| name2 = Jaroslav
| url = http://portal.med.muni.cz/clanek-10-automaticka-analyza-moci.html
| source_name = Automatická analýza moči
| publisher = Portál Lékařské fakulty Masarykovy univerzity
| year = 2005
| date_revision = 2011-10-27
| cited = 2011-11-25
}}
=== Used literature  ===
* {{Cite
| type = book
| surname1 = Schneiderka
| name1 = Petr
| ohters = yes
| title = Kapitoly z klinické biochemie
| edition = 2
| publisher = Karolinum
| place = Praha
| year = 2004
| isbn = 80-246-0678-X
| range = 365
}}
[[Category:Clinical biochemistry]]
</noinclude>