Many reagent commercial test strip are available from different manufacturers. Some of these test strip are base on the modifications of previously manufactured test strip from another company.
For example Ames test is the modification of Ehrlich's test.
Mechanism of reaction
The strip is incorporated with p-dimethylaminobenzaldehyde, which then reacted with uroblinogen if present in the urine to yield brown-orange colour. Note that the test is not accurate for urinoblinogen investigation. But Bllugen test strip is accurate for uroblinogen investigation via urine.
On the Bllugen test strip, the p-methoxybenzenediazonium tetrafluorobote to give pink red azo dye. This test strip determine the present of normal uroblinogen and the increase of it in the urine, but did not detect if it is absent.
Point to know is that either the test strip is single of double the laboratory procedure is the same.
- Area of the test strip is dip into fresh void and well mixed urine.
Leave it for 10 second and remove it from the urine, remove excess urine by tapping the removed trip on the egde of the container s
Leave it for some times base on manufacturer instructions.
The colour produce on the strip should be compared with the colour chart on the container.
The most available reagent test strip are
Urobilistix (Ames): is a single strip test that have it reagent inserted into the absorbent area made up of plastic strip. Although these test strip is not accurate for urobilinogen investigation, but it give fast convenient test for urobilinogen.
The strip is calibrated on following figure; 1.6, 16, 33, 66, 131, and 167micromol/L.
Normal result will yield up to 16micromol/L of urobilinogen. The result should be read approximately after 60 seconds.
Bllugen (Boehringer): this strip is different from that of uroblilistix, the fact that Bllugen is made for investigating two parameters, which include uroblinogen and bilirubin's. The reaction of bllugen is read approximately after 10second why that uroblilistix is read approximately after 60 second.
Bllugen is calibrated in the following scales; 17, 70, 149, and 200micromol/L respectively. Note that when high concentration of formaldehyde is present, for example above 200mg/100ml, the strip may yield false negative result.
Result: normal urine will exhibit no colour or may give value not above 16micromol/L.
The following conditions may led to high concentration of urine;
- Liver Cirrhosis
When a patient have paralytic enterpcolitis, it may led to high production of urobilinogen in the intestines
Hemolytic conditions; when a patients have hemolytic disease, it led to high level of bilirubin's production, this also trigger large amount of urobilinogen.
Hepatic disease; when a patient have hepatic congestion, it let to less excretion of urobilinogen by the liver, as such urobilinogen passed into general circulation which in turn subject the kidney to excesses excretion of the urobilinogen.
Lower concentration of urobilinogen
1.bile duct blocked: a patient with obstruction of bile duct may experience blocked of flow of bilirubin into the intestine.as such led to lack of bilirubin's to be converted to uroblinogen.
When there hindrance of production of urobilinogen, it can led to destruction of normal bacteria flora of the intestine.
Lack of conjugation of bilirubin's to to soluble one. When this happen, it mat not excreted via urine.