Urine test strip
Encyclopedia
A urine test strip or dipstick is a basic diagnostic
instrument used to determine pathological
changes in the urine
in standard urinalysis
. A standard urine test strip may comprise up to 10 different chemical pads or reagents which react
(change colour) when immersed in, and then removed from, a urine sample. The test can be read between 60 and 120 seconds after dipping. Routine testing of the urine with multiparameter strips is the first step in the diagnosis of a wide range of diseases.
Many renal and urinary tract diseases may be asymptomatic
for a long period of time. Routine urinalysis is recommended as a basic yet fundamental step in identifying renal damage and / or urinary tract disease at an early stage, especially in high risk populations such as diabetics, the hypertensive, African Americans, Polynesians
, and those with a family history
.
Around 30–40% of type I diabetics and around 20% of type II diabetics suffer in time from a nephropathy, and early recognition of diabetes is therefore of major significance for the further state of health of these patients.
In many liver diseases the patients often show signs of pathology only at a late stage. Early diagnosis allows appropriate therapeutic measures to be instituted in good time, avoiding consequential damage and further infections.
, (accompanied by Jaundice
), Cirrhosis
both in hospitals and in general practice. The aim of screening is early identification of likely patients by examination of large groups of the population. The importance of screening for diabetes and kidney disease amongst high risk populations is becoming very high.
with the aid of urine test strips allows a health professional to check on the results of the prescribed therapy, and if necessary to introduce any changes into the course of therapy..
s is a popular example as sufferers monitor their own urine on a daily basis and discuss the results with their health professional.
It was only towards the end of the 18th century that doctors interested in chemistry turned their attention to the scientific basis of urinalysis
and to its use in practical medicine.
may be microscopically analyzed to further pinpoint a diagnosis.
Medical diagnosis
Medical diagnosis refers both to the process of attempting to determine or identify a possible disease or disorder , and to the opinion reached by this process...
instrument used to determine pathological
Pathology
Pathology is the precise study and diagnosis of disease. The word pathology is from Ancient Greek , pathos, "feeling, suffering"; and , -logia, "the study of". Pathologization, to pathologize, refers to the process of defining a condition or behavior as pathological, e.g. pathological gambling....
changes in the urine
Urine
Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...
in standard urinalysis
Urinalysis
A urinalysis , also known as Routine and Microscopy , is an array of tests performed on urine, and one of the most common methods of medical diagnosis...
. A standard urine test strip may comprise up to 10 different chemical pads or reagents which react
Chemical reaction
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...
(change colour) when immersed in, and then removed from, a urine sample. The test can be read between 60 and 120 seconds after dipping. Routine testing of the urine with multiparameter strips is the first step in the diagnosis of a wide range of diseases.
Diseases Identified with a Urine Test Strip
With the aid of routine examinations early symptoms of the following three groups are identified:- Diseases of the kidneys and the urinary tract
- Carbohydrate metabolism disorders (diabetes mellitus)
- Liver diseases and haemolytic disorders
Diseases of the kidneys and urinary tract
Screening parameters:- LeukocytesWhite blood cellWhite blood cells, or leukocytes , are cells of the immune system involved in defending the body against both infectious disease and foreign materials. Five different and diverse types of leukocytes exist, but they are all produced and derived from a multipotent cell in the bone marrow known as a...
- Known as Leukocyturia - NitriteNitriteThe nitrite ion has the chemical formula NO2−. The anion is symmetric with equal N-O bond lengths and a O-N-O bond angle of ca. 120°. On protonation the unstable weak acid nitrous acid is produced. Nitrite can be oxidised or reduced, with product somewhat dependent on the oxidizing/reducing agent...
- Known as Nitrituria - ProteinProteinProteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
- Known as ProteinuriaProteinuriaProteinuria means the presence of anexcess of serum proteins in the urine. The protein in the urine often causes the urine to become foamy, although foamy urine may also be caused by bilirubin in the urine , retrograde ejaculation, pneumaturia due to a fistula, or drugs such as pyridium.- Causes...
also see AlbuminuriaAlbuminuriaAlbuminuria is a pathological condition wherein albumin is present in the urine. It is a type of proteinuria.Measurement=The amount of protein being lost in the urine can be quantified by collecting the urine for 24 hours, measuring a sample of the pooled urine, and extrapolating to the volume...
and MicroalbuminuriaMicroalbuminuriaMicroalbuminuria occurs when the kidney leaks small amounts of albumin into the urine, in other words, when there is an abnormally high permeability for albumin in the renal glomerulus.-Diagnosis:... - BloodRed blood cellRed blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...
- Known as HematuriaHematuriaIn medicine, hematuria, or haematuria, is the presence of red blood cells in the urine. It may be idiopathic and/or benign, or it can be a sign that there is a kidney stone or a tumor in the urinary tract , ranging from trivial to lethal... - specific gravitySpecific gravity (kidney)Specific gravity, in the context of clinical pathology, is a urinalysis parameter commonly used in the evaluation of kidney function and can aid in the diagnosis of various renal diseases.-Background:...
- pHPHIn chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
Many renal and urinary tract diseases may be asymptomatic
Asymptomatic
In medicine, a disease is considered asymptomatic if a patient is a carrier for a disease or infection but experiences no symptoms. A condition might be asymptomatic if it fails to show the noticeable symptoms with which it is usually associated. Asymptomatic infections are also called subclinical...
for a long period of time. Routine urinalysis is recommended as a basic yet fundamental step in identifying renal damage and / or urinary tract disease at an early stage, especially in high risk populations such as diabetics, the hypertensive, African Americans, Polynesians
Polynesians
The Polynesian peoples is a grouping of various ethnic groups that speak Polynesian languages, a branch of the Oceanic languages within the Austronesian languages, and inhabit Polynesia. They number approximately 1,500,000 people...
, and those with a family history
Heredity
Heredity is the passing of traits to offspring . This is the process by which an offspring cell or organism acquires or becomes predisposed to the characteristics of its parent cell or organism. Through heredity, variations exhibited by individuals can accumulate and cause some species to evolve...
.
Specific kidney & urinary tract diseases able to be identified
Chronic kidney disease, GlomerulonephritisGlomerulonephritis
Glomerulonephritis, also known as glomerular nephritis, abbreviated GN, is a renal disease characterized by inflammation of the glomeruli, or small blood vessels in the kidneys...
Carbohydrate metabolism disorders
- GlucoseGlucoseGlucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
- Identified as GlycosuriaGlycosuriaGlycosuria or glucosuria is the excretion of glucose into the urine. Ordinarily, urine contains no glucose because the kidneys are able to reclaim all of the filtered glucose back into the bloodstream. Glycosuria is nearly always caused by elevated blood glucose levels, most commonly due to... - Ketones - Identified as KetonuriaKetonuriaKetonuria is a medical condition in which ketone bodies are present in the urine.It is seen in conditions in which the body produces excess ketones as an alternative source of energy. It is seen during starvation or more commonly in type I diabetes mellitus...
(also see ketoacidosisKetoacidosisKetoacidosis is a metabolic state associated with high concentrations of ketone bodies, formed by the breakdown of fatty acids and the deamination of amino acids. The two common ketones produced in humans are acetoacetic acid and β-hydroxybutyrate....
and ketosisKetosisKetosis is a state of elevated levels of ketone bodies in the body. It is almost always generalized throughout the body, with hyperketonemia, that is, an elevated level of ketone bodies in the blood. Ketone bodies are formed by ketogenesis when the liver glycogen stores are depleted...
)
Around 30–40% of type I diabetics and around 20% of type II diabetics suffer in time from a nephropathy, and early recognition of diabetes is therefore of major significance for the further state of health of these patients.
Liver diseases and haemolytic disorders
- UrobilinogenUrobilinogenUrobilinogen is a colourless product of bilirubin reduction. It is formed in the intestines by bacterial action. Some urobilinogen is reabsorbed, taken up into the circulation and excreted by the kidney. This constitutes the normal "enterohepatic urobilinogen cycle".Increased amounts of bilirubin...
- Identified as Urobilinogenuria - BilirubinBilirubinBilirubin is the yellow breakdown product of normal heme catabolism. Heme is found in hemoglobin, a principal component of red blood cells. Bilirubin is excreted in bile and urine, and elevated levels may indicate certain diseases...
- Identified as BilirubinuriaBilirubinuriaIn medicine, bilirubinuria is an abnormality where conjugated bilirubin is detected in the urine.The term "biliuria" is very similar, but more general. It refers to the presence of any bile pigment in the urine.-Causes:...
In many liver diseases the patients often show signs of pathology only at a late stage. Early diagnosis allows appropriate therapeutic measures to be instituted in good time, avoiding consequential damage and further infections.
Specific liver diseases and haemolytic disorders able to be identified
Liver DiseaseLiver disease
Liver disease is a broad term describing any single number of diseases affecting the liver.-Diseases:* Hepatitis, inflammation of the liver, caused mainly by various viruses but also by some poisons , autoimmunity or hereditary conditions...
, (accompanied by Jaundice
Jaundice
Jaundice is a yellowish pigmentation of the skin, the conjunctival membranes over the sclerae , and other mucous membranes caused by hyperbilirubinemia . This hyperbilirubinemia subsequently causes increased levels of bilirubin in the extracellular fluid...
), Cirrhosis
Cirrhosis
Cirrhosis is a consequence of chronic liver disease characterized by replacement of liver tissue by fibrosis, scar tissue and regenerative nodules , leading to loss of liver function...
Detection limit
The detection limit of a test is that concentration, at which the test starts to turn from negative to positive. Although the detection limit may vary between urine samples, the detection limit is defined as that concentration of the analyte which results in a positive reaction in 90 percent of the examined urines.| Parameter | Reference range Reference range In health-related fields, a reference range or reference interval usually describes the variations of a measurement or value in healthy individuals... |
Practical detection limit |
|---|---|---|
| Specific Gravity Reference range Physiological range |
1.016 - 1.022 1.002 - 1.035 |
Range: 1.000 - 1.030 |
| pH value First morning urine During the day |
5 - 6 4.8 - 7.4 |
Range: 5 - 9 |
| Leukocytes Reference range Grey zone |
< 10 Leu/µl 10 - 20 Leu/µl |
10-25 Leu/µl |
| Nitrite | - | 0.05 mg/dl (11 µmol/l) |
| Protein Albumin |
< 2 mg/dl |
6 mg/dl |
| Glucose First morning urine During the day |
< 20 mg/dl < 30 mg/dl |
40 mg/dl (2.2 mmol/l) |
| Ketones Acetoacetic acid Acetone |
< 5 mg/dl - |
5 mg/dl (0.5 mmol/l) 40 mg/dl (7 mmol/l) |
| Urobilinogen | < 1 mg/dl | 0.4 mg/dl (7µmol/l) |
| Bilirubin | < 0.2 mg/dl | 0.5 mg/dl (9µmol/l) |
| Blood Erythrocytes Hemoglobin |
0 - 5 Ery/µl - |
5 Ery/µl 0.03 mg/dl Hb |
Uses for Urine Test Strips
Urine test strips can be used in many areas of the healthcare chain including screening for routine examinations, treatment monitoring, self-monitoring by patients and/or general preventive medicine.Screening
Urine test strips are used for screeningScreening (medicine)
Screening, in medicine, is a strategy used in a population to detect a disease in individuals without signs or symptoms of that disease. Unlike what generally happens in medicine, screening tests are performed on persons without any clinical sign of disease....
both in hospitals and in general practice. The aim of screening is early identification of likely patients by examination of large groups of the population. The importance of screening for diabetes and kidney disease amongst high risk populations is becoming very high.
Treatment Monitoring
Treatment monitoringTherapy
This is a list of types of therapy .* Adventure therapy* Animal-assisted therapy* Aquatic therapy* Aromatherapy* Art and dementia* Art therapy* Authentic Movement* Behavioral therapy* Bibliotherapy* Buteyko Method* Chemotherapy...
with the aid of urine test strips allows a health professional to check on the results of the prescribed therapy, and if necessary to introduce any changes into the course of therapy..
Self-monitoring by Patients
Self monitoring with urine test strips under the guidance of a health professional is an effective method for monitoring the disease state. This applies particularly to diabetics, where the idea of self monitoring of the metabolic status (determinations of glucose and ketones) is self-evident.General Preventive Medicine
Unsolicited self testing has become a popular measure in recent years as various urine test strips become available via pharmacy and online stores. Self monitoring for frequent urinary tract infectionUrinary tract infection
A urinary tract infection is a bacterial infection that affects any part of the urinary tract. Symptoms include frequent feeling and/or need to urinate, pain during urination, and cloudy urine. The main causal agent is Escherichia coli...
s is a popular example as sufferers monitor their own urine on a daily basis and discuss the results with their health professional.
History of the modern day test strip
In many cultures urine was once regarded as a mystical fluid, and in some cultures it is still regarded as such to this day. Its uses have included wound healing, stimulation of the body’s defences, and examinations for diagnosing the presence of diseases.It was only towards the end of the 18th century that doctors interested in chemistry turned their attention to the scientific basis of urinalysis
Urinalysis
A urinalysis , also known as Routine and Microscopy , is an array of tests performed on urine, and one of the most common methods of medical diagnosis...
and to its use in practical medicine.
- 1797 - Carl Friedrich Gärtner(1772–1850) expressed a wish for an easy way of testing urine for disease at the patient’s bedside.
- 1797 - William Cumberland CruikshankWilliam Cumberland CruikshankWilliam Cumberland Cruikshank was a British chemist and anatomist. He was the author of The Anatomy of the Absorbing Vessels of the Human Body, which was first published in 1786....
(1745–1800) described for the first time the property of coagulation on heating, exhibited by many urines.
- 1827 - English physician Richard BrightRichard Bright (physician)Richard Bright was an English physician and early pioneer in the research of kidney disease.He was born in Bristol, Gloucestershire, the third son of Sarah and Richard Bright Sr., a wealthy merchant and banker. Bright Sr. shared his interest in science with his son,encouraging him to consider it...
describes the clinical symptom of nephritis in “Reports of Medical Cases.”
- 1840 - The arrival of chemical urine diagnostics aimed at the detection of pathological urine constituents
- 1850 - Parisian chemist Jules Maumené (1818–1898) develops the first “test strips” when he impregnated a strip of merino wool with “tin protochloride” (stannous chloride). On application of a drop of urine and heating over a candle the strip immediately turned black if the urine contained sugar.
- 1883 - English physiologist George OliverGeorge OliverGeorge Oliver may refer to:*George Oliver , Roman Catholic priest and historian*George Oliver , English physician*George Oliver *George Oliver , British politician...
(1841–1915) markets his “Urinary Test Papers”
- approx. 1900 - ReagentReagentA reagent is a "substance or compound that is added to a system in order to bring about a chemical reaction, or added to see if a reaction occurs." Although the terms reactant and reagent are often used interchangeably, a reactant is less specifically a "substance that is consumed in the course of...
papers become commercially obtainable from the chemical company of Helfenberg AG.
- 1904 - A test for the presence of blood by a wet-chemical method using benzidine became known.
- approx. 1920 - Viennese chemist Fritz FeiglFritz FeiglFritz Feigl was an Austria-born chemist. He taught at the University of Brazil.-Biography:Feigl was born and studied in Vienna, but owing to his military service in the First World War he had to interrupt his studies. He received his Ph.D. for work with Wilhelm Schlenk in 1920...
(1891–1971) publishes his technique of “spot analysis".
- 1930s - Urine diagnostics makes major progress as reliability improves and test performance becomes progressively easier.
- 1950s - Urine test strips in the sense used today were first made on industrial scale and offered commercially.
- 1964 - The company Boehringer Mannheim, today a top leader on the world market under the name of RocheRoche DiagnosticsRoche Diagnostics Division is a subsidiary of Hoffmann-La Roche which manufactures equipment and reagents for research and medical diagnostic applications. Internally, it is organized into five major business areas: Roche Applied Science, Roche Professional Diagnostics, Roche Diabetes Care, Roche...
, launched its first Combur test strips. Even though the test strips have changed their external appearance little since the 1960s, they now contain a number of revolutionary innovations. New impregnation techniques, more stable color indicators, and the steady improvement in color gradation have all contributed to the fact that the use of urine test strips has now become established in clinical and general practice as a reliable diagnostic instrument. The parameter menu offered has steadily grown longer in the intervening decades.
Ascorbic Acid Interference
Ascorbic acid (vitamin C) is known to interfere with the oxidation reaction of the blood and glucose pad on common urine test strips. Some urine test strips are protected against the interference with iodate, which eliminates ascorbic acid by oxidation.Automated Urine Test Strip Analyzers
Automatic analysis of urine test strips using automated urine test strip analyzers is a well established practice in modern day urinalysis.Urinary Sediment
During routine screening, if a positive test for leukocytes, blood, protein, nitrite, and a pH greater than 7 is identified, the urine sedimentSedimentation
Sedimentation is the tendency for particles in suspension to settle out of the fluid in which they are entrained, and come to rest against a barrier. This is due to their motion through the fluid in response to the forces acting on them: these forces can be due to gravity, centrifugal acceleration...
may be microscopically analyzed to further pinpoint a diagnosis.