This test is done to look for protein, crystals, blood, nitrites and white blood cells in the urine. The results of the microscopic analysis are made available in 1 to 1 ½ hours.
Urine Chemical Dipstick Analysis
The urine produced has pH value of 6.0 to about 7.4. However, depending on our body’s metabolic needs, urinary pH may range from as low as 4.5 to as high as 8.0.
Specific gravity indicates the ability of the kidney to concentrate or dilute the urine compare to that of plasma.
Dipstick screening for protein is done on whole urine, and is used as a screening tool for urinary tract infections (UTI’s), kidney diseases etc. Proteins may also be found due to vaginal discharge contamination.
A positive nitrite test indicates that bacteria may be present, indicating a urinary tract infection. Bacteria such as Escherichia coli are more likely to give a positive test. This will require a urine culture and sensitivity examination to confirm a UTI.
A positive leucocyte esterase test results from the presence of white blood cells (WBCs), which is indicative of a probable bacterial infection
Microscopic Urinalysis
A sample urine is spun down to collect the solid material, which is examined to identify crystals, casts, bacteria, squamous cells and other cell types. The following descriptions are some significant microscopic observations.
Haematuria is the presence of red blood cells in urine and is associated with pathology; such as UTI’s, kidney or bladder stones, or in tumourous/cancerous growth of the kidney or bladder. RBCs may clump together to form red cell casts or stones, which usually indicate a kidney disease like glomerulonephritis.
White Blood Cells (WBCs) may appear with infection in either the upper or lower urinary tract or with kidney diseases like acute glomerulonephritis. White blood cells from the vagina, especially in the presence of vaginal and cervical infections, may contaminate the urine.
Epithelial cells
Renal tubular epithelial cells normally slough into the urine in small numbers. However, with Nephrotic Syndrome and in conditions leading to kidney tissue damage, the number of the cells is increased.
Transitional epithelial cells line the collecting system of the kidney, the ureters, bladder and the urethra. Abnormal-looking transitional epithelial cells can indicate cancerous change.
Squamous epithelial cells from the skin surface or from the outer urethra can appear in urine. Excessive numbers represent possible contamination of the specimen from bacteria found on external skin surfaces.
When present on microscopic evaluation, urinary casts hold medical significance Although the most common forms are benign, other forms are indicative of certain types of kidney disease. Hyaline casts, granular casts, waxy casts are all different types of cast that can be found in urine specimens. They can occur in situations like: dehydration, after vigorous exercise, which indicate chronic renal disease and renal failure.
Bacteria are common in urine specimens because of the abundant normal microbial flora of the vagina or urethral opening and because of their ability to rapidly multiply in urine standing at room temperature. Therefore, microbial organisms found in all but the most scrupulously collected urines should be interpreted in view of clinical symptoms. Diagnosis of suspected urinary tract infection requires bacterial culturing. Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa and Neiserria gonorrhoeae are some of the bacteria that do cause UTI.
Bacterial culturing
Yeast cells may be contaminants or represent a true yeast infection. The commonest is Candida albicans, a common culprit causing vaginal candiasis, which may colonise bladder, urethra, or vagina.
Common crystals seen even in healthy patients include calcium oxalate, triple phosphate crystals and amorphous phosphates.
Uncommon crystals include: cystine crystals in urine of neonates with congenital cystinuria or severe liver disease, tyrosine crystals with congenital tyrosinosis or marked liver impairment, or leucine crystals in patients with severe liver disease or with maple syrup urine disease. These are the crystals of clinical significance and should be paid due attention when they are observed in urine specimens.
*Urinalysis should not be performed if the patient had mensus, sexual intercourse or cervical PAP in the past 5-7 days to avoid contamination of the urine.
Urodynamic studies are a group of tests to assess how the bladder and urethra control the storage and release of urine. Urodynamic tests help your doctor or nurse explain symptoms such as:
- Incontinence
- Frequent urination
- Sudden, strong urges to urinate
- Problems starting a urine stream
- Problems emptying your bladder completely
Preparing for the Test
Please drink some water, and come for assessment with a full bladder.
Types of Urodynamic Tests
1) Uroflowmetry (Measurement of Urine Speed and Volume)
An uroflowmeter automatically measures the amount of urine and the flow rate - that is, how fast the urine is expelled. You will be asked to urinate into a toilet that contains a collection device and scale. A computer generated graph shows changes in flow rate from second to second so the doctor can see the peak flow rate and how many seconds it took to complete urination. Results of this test will be abnormal if the bladder muscle is weak or urine flow is obstructed.
2) Measurement of Post-void Residual
After you have voided, you may still have some urine remaining in your bladder. To measure this post-void residual, the nurse may use a catheter that can be gently inserted into the urethra or perform the measurement using ultrasound. A post-void residual of more than 50 ml requires further evaluation.
3) Cystometry (Measurement of Bladder Pressure)
A cystometrogram (CMG) measures how much your bladder can hold, how much pressure builds up inside your bladder as it stores urine, and how full it is when you feel the urge to urinate. The nurse will use a catheter to empty your bladder completely. A fine catheter will be inserted into the bladder and another placed in the rectum to record pressure there. Your bladder is slowly filled with sterile water. During this time you will be asked how your bladder feels and when you feel the need to urinate. The volume of water and the bladder pressure will be recorded. You are asked to cough or strain during this procedure to identify a variety of bladder conditions. The procedure is generally well tolerated by patients.
4) Pressure Flow Study
At the end of cystometry, you will be asked to empty your bladder. Measurements of the bladder pressure required to urinate, and the flow rate that a given pressure generates are recorded. This pressure flow study helps to identify bladder outlet obstruction, which can occur with a prolapsed bladder, a weakened bladder which cannot contract adequately, a urethral stricture or rarely after a surgical procedure for urinary incontinence.
5) Electromyography (Measurement of Nerve Impulses)
If your doctor or nurse thinks that your urinary problem is related to nerve or muscle damage, you may be asked to undergo an electromyography. This test measures muscular contraction in and around the urethral sphincter by using special sensors. The sensors are placed on the skin near the urethra and rectum. Muscle activity is recorded on a machine. The patterns of the impulses will show whether the messages sent to the bladder and urethra are coordinated correctly.
* Time for completion of typical Urodynamic testing: 30 min
What is ultrasound?
Ultrasound is a high frequency sound emitted and detected by specialised equipment that generates an image of the organ(s) looked at.
What does an ultrasound scan involve?
You will be asked to lie down and an operator will place a probe on your skin, over the part of your body to be examined. Lubricating jelly will be put on your skin so the probe makes good contact with your body. The ultrasound waves are projected through the various structures in the body; and the probe detects the returning echoes, which are analysed by the machine. Information is displayed as a picture on the monitor in real-time, so detailed assessments can be made.
What is an ultrasound test used for?
We use ultrasound in urogynaecology to examine the pelvis, bladder, kidneys and the ureters.
What should I do to prepare for the test?
You should have a full bladder for trans-abdominal scans. You should eat and drink normally before and after the test unless otherwise instructed; and if on regular medication, continue your medications.
* Time for completion of scan: 5-30 minutes