Why is the three tube test for hematuria done?
The three tube test is performed to determine the location of bleeding in the urinary tract.
The three tube test also known as the three container method.
What is Hematuria?
Blood in the urine is Hematuria.
How is Hematuria defined?
Hematuria is defined as the presence of at least 5 red blood cells/HPF in 3 of 3 consecutive centrifuged specimens obtained at least 7 days apart.
The Blood may be visible in the urine, or it may be identified with a test.
What are the types of Hematuria?
Hematuria can be gross or microscopic. Gross hematuria is visible blood in the urine. Microscopic hematuria refers to the detection of blood on urinalysis or urine microscopy.
Hematuria can be intermittent or persistent. Hematuria may be asymptomatic or symptomatic and may be associated with other urinary tract abnormalities. Hematuria is often first encountered by the primary care provider.
What causes Hematuria?
Hematuria is caused by the below conditions
- Excessive calcium in the urine
- Stones in the Kidney
- Cancer of the urinary tract.
- Conditions that are passed from parent to child (inherited conditions).
- Exercise that requires a lot of energy.
How the three tube test is done?
The three tube test is done using three consecutive samples
Three consecutive samples of the urine stream are collected as:
- 10 to 15 mL of the first urine sample
- 30 to 40 mL of the midstream urine sample
- 5 to 10 mL of the last urine sample
What is the procedure of extracting three consecutive samples
Initially the bladder is emptied by passing urine into a series of 3 ounce test tubes
Then, The contents of the first test tube and the last test tube are examined;
The first tube contains the washings from the anterior urethra,
the second test tube comprises of the material from the bladder, and the last test tube constitutes the material from the posterior urethra, prostate, and seminal vesicles
How to understand the results of the three tube test?
The results of the three tube test can be interpreted as Initial hematuria, Terminal hematuria
- Initial hematuria
- Terminal hematuria
- Hematuria in all three samples is seen in lesions that may be anywhere above the bladder neck (bladder, ureters, or kidneys).
Hematuria (or predominance of RBCs on urine microscopy) primarily in the first sample
What does the initial hematuria indicate?
The initial hematuria is suggestive of an anterior urethral source of bleeding
What does the terminal hematuria indicate?
Terminal Hematuria primarily at the end of the urine stream is suggestive of a lesion at the bladder trigone (bladder neck) or a posterior urethra.
Terminal hematuria is defined as passage of clear urine with blood or blood-stained urine right at the end of the urine stream (“blood notes just at the end of the urine flow”).
Total hematuria is defined as blood-stained urine throughout the entire duration of the urine flow with no ability to readily differentiate between urine and blood.