Difference Between Urinalysis and Urine Culture

The key difference between urinalysis and urine culture is that the urinalysis refers to simply an analysis of urine while the urine culture test refers to the cultivation of microorganisms in urine to determine the urine infections.

Urine is an excretory metabolic product of kidney. It consists of water and nitrogenous wastes such as urea, etc. Normal composition of the urine can change due to several reasons such as urinary tract infections, kidney disorders, liver problems, diabetes, etc. Therefore, to detect and diagnose above-mentioned conditions or diseases, several tests can be performed, including routine urinalysis and urine culture.

CONTENTS

1. Overview and Key Difference
2. What is Urinalysis
3. What is Urine Culture
4. Similarities Between Urinalysis and Urine Culture
5. Side by Side Comparison – Urinalysis vs Urine Culture in Tabular Form
6. Summary

What is Urinalysis?

Urinalysis is a common test to analyze the urine. It is a simple and easy test that any healthcare setting can perform. Also, urinalysis is an inexpensive test. But, it is really important to collect an uncontaminated urine sample of around 30 – 60 ml. Therefore, it uses a sterile cup to collect the urine sample. Also, a method to collect a sample is to pass a catheter through the urethra to the bladder and collect the sample. In urinalysis, it is necessary to perform the test within an hour of the collection of the sample. Therefore, it has to reach the laboratory within that time. Otherwise, the collection center should keep the sample in a refrigerator or add preservatives until use.

Figure 01: Urinalysis

In laboratories, there are three main ways to perform a urinalysis. They are macroscopic parameters such as colour, clarity, etc., reagent strip (chemical analysis), and microscopic observation. The urinalysis reveals the substances present in the urine. Also, the microscopic observation can show certain microbes present in the urine.

What is Urine Culture?

Urine does not contain microorganisms unless there is an infection or an abnormal condition. Urine culture is a technique that detects urinary tract infections. By allowing the microorganisms to grow under laboratory conditions on culture media, it is possible to detect the bacteria and other microbes present in the urine sample. However, urine culture is not a part of a routine urinalysis. But, here too, it is necessary to collect an uncontaminated urine sample by inserting a sterile catheter.

Figure 02: Urine Culture

The next step is to transfer a small amount of urine into a medium that promotes the growth of microorganisms. If microbes grow in the medium, the urine culture is positive. Otherwise, it is a negative test. Herein, it is possible to identify the grown microbes by utilizing a microscope or chemical analysis. Then, the treatment to the patient differs based on the type of infection identified. Urinary tract infections are more common in females than males due to a short urethra that they have.

What are the Similarities Between Urinalysis and Urine Culture?

• Urinalysis and Urine Culture are two urine tests.
• Both tests require a small urine sample.
• Furthermore, they require uncontaminated samples.
• Also, both methods reveal urinary tract infections and other health problems such as diabetes, kidney disorders, etc.

What is the Difference Between Urinalysis and Urine Culture?

Urinalysis reveals the appearance, concentration and content of urine while urine culture reveals the infections in the urinary tract. This is the major difference between urinalysis and urine culture. Another difference between urinalysis and urine culture is that the urinalysis do not identify the growth of microbes present in the urine, but it is the main activity in the urine culture. Furthermore, urinalysis uses reagent strips while urine culture does not use reagent strips.

Summary – Urinalysis vs Urine Culture

Urinalysis and urine culture are two common urine tests to detect problems in urine. Urine culture differs from the urinalysis since it involves culturing of microbes, mainly bacteria, present in the urine sample. In contrast, urinalysis checks the appearance, composition and concentration of the urine. However, both methods are important in diagnosis and any healthcare setting can perform these tests. Thus, this summarizes the difference between urinalysis and urine culture.

Reference:

1.“Urinalysis Test Results and Interpretation of Urine Test.” MedicineNet. Available here  
2.“Urinalysis and Urine Culture – Kidney and Urinary Tract Disorders – MSD Manual Consumer Version.” MSD Manual Professional Edition. Available here   

Image Courtesy:

1.”9183250624″ by Dominic Alves (CC BY 2.0) via Flickr
2.”Urine cultured on Oxoid Brilliance UTI Agar plate”By Nathan Reading from Halesowen, UK – Urine Culture – Oxoid Brilliance U.T.I. Agar, (CC BY 2.0) via Commons Wikimedia  

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