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.
With the aid of routine examinations early symptoms of the following three groups are identified:
Screening parameters:
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.[1]
Chronic kidney disease, Glomerulonephritis
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.
Liver Disease, (accompanied by Jaundice), Cirrhosis
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 |
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 |
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.
Urine test strips are used for screening 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 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 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.
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 infections is a popular example as sufferers monitor their own urine on a daily basis and discuss the results with their health professional.
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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 and to its use in practical medicine.
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.[3]
Automatic analysis of urine test strips using automated urine test strip analyzers is a well established practice in modern day urinalysis.
During routine screening, if a positive test for leukocytes, blood, protein, nitrite, and a pH greater than 7 is identified, the urine sediment may be microscopically analyzed to further pinpoint a diagnosis.