Urine has been used in medical research for years to identify biomarkers associated with diseases and to track health changes that occur over time. Appropriately, urine samples are vital in clinical research. 

Due to the ability to easily collect and store a urine sample, it is possible to easily integrate it into a clinical trial while still providing both patients and researchers with a quick turnaround time.

Urine Specimen in Clinical Research

Depending on the research question, different types of urine specimen collections can be used. 

Urine specimen collections used in clinical research are either immediate collections such as clean catch (mid-stream) urine samples, suprapubic aspiration, or urethral catheterization. 

Alternatively, urine can be collected over a period of time (usually 8 or 24 hours).

Immediate collection urine samples are collected by directly accessing the bladder invasively or by allowing the initial flow of urine to pass, then collecting the urine from the center of the stream. Collection of urine over a period of time can be done similarly but by also implementing special large storage containers.

Where do urine specimens fit into clinical research? 

Urine specimens are an often-overlooked alternative to blood-based biospecimens, but they have the potential to provide unique information about a patient’s health that other biospecimens cannot. 

Urine specimens have advantages over blood specimens for certain tests because they offer a larger sample size and require minimal processing or centrifugation

In addition, urine specimens are non-invasive and can be taken multiple times with no risk of side effects observed with repeated blood sampling.

For example, if the purpose of the study is to track an investigational intervention over time, urine specimens should be collected periodically at regular intervals throughout the study. If the study is designed to report pharmacokinetic or pharmacodynamic research, urine specimens can be collected pre-dose, at peak concentrations, and post-dose to quantify the extent of urinary drug metabolism if applicable.

What Are the Main Types of Immediate Urine Collection?

When deciding when to collect a urine specimen, it is important to consider the purpose of the study and the potential confounding factors. 

Clean Catch

Urine collections using the clean catch (mid-stream) technique are mainly used in clinical research when the research question is focused on analyzing a single urinary specimen. 

This technique is widely used in clinical studies to determine real-time infections or metabolic disturbances by measuring the presence of urinary pathogens or detecting urinary biomarkers of disease

Clean catch is non-invasive and does not require any special training to implement, making it the most popular method of urine specimen collection in medicine and research.

Although this method is easy to collect and convenient, it has its limitations. Clean catch specimens are subject to contamination from fecal and vaginal bacteria, making it difficult at times to accurately identify a specific pathogen or biomarker. In addition, specimens can also become contaminated when they are improperly stored or handled.

Suprapubic Aspiration

Suprapubic aspiration is another type of urine collection used in both medicine and clinical research. This method involves inserting a needle into the bladder and aspirating urine. While this method is invasive, it is useful for obtaining an uncontaminated sample of urine for accurate and reliable results. 

This method is primarily used in research studies when a single, uncontaminated sample of urine is needed without the need for sterile repeated sampling.

Disadvantages of using a suprapubic aspiration urine sample collection include the need for a trained individual to collect the sample, the risk of a bladder infection, and the risk of puncturing the bladder wall or kidney. The technique is uncomfortable for the patient and requires a trip to a hospital, facility, or clinic to be performed. 

This method can also be expensive, as the technique is invasive and must be performed by a trained individual while under anesthesia.

Urethral Catheterization

Urethral catheterization is the third type of immediate urine collection method. This method involves inserting a catheter through the urethra into the bladder in order to collect the urine. 

Like suprapubic aspiration, this method is used when a single, uncontaminated sample is needed, usually when the patient is unable to adequately void or pass urine.

Urethral catheterization, while less invasive than suprapubic aspiration, is considered to be more invasive than immediate collection methods and should be used only when necessary. A foley catheter is commonly in place prior to collecting a urethral catheterization sample.

Disadvantages of urethral catheterization include the need for trained personnel to insert the catheter, the risk of a bladder infection and the risk of puncturing the bladder wall or kidney. Additionally, the technique is uncomfortable for the patient and requires a trip to the hospital or clinic to be performed.

What Is Extended-Time Urine Collection?

Urine collected over a period of time, either in an 8 or 24-hour urine collection, is mainly used in research studies to analyze the excretion rate of drugs and identify abnormalities in kidney functions over time. 

This method is beneficial for measuring the rate at which various drugs are metabolized and for determining the level of creatinine and metabolites in the body more accurately than from a single urine collection. 

Most commonly, this collection method is used to obtain a more accurate picture of an individual’s renal function over immediate collection.

Although 8 and 24-hour urine collections are popular in clinical research, they have some drawbacks. 

For instance, they are a time-consuming process and require the patient or provider to collect the sample over 8 or 24 hours, which can be difficult in some settings.

Additionally, the urine collections sit at room temperature and therefore are prone to contamination which can affect the accuracy of the results. 

Above all else, the collection containers are bulky, hard to ship or store, and may be difficult for some individuals to take with them wherever they go.

How To Decide What Type of Urine Specimen To Collect

Ultimately, the choice of which type of urine collection to use depends on the research question, the participant’s ability to collect the sample, and the need for a single uncontaminated sample. 

Immediate collection, such as clean catch, suprapubic aspiration, or urethral catheterization, is recommended when the research question requires a single sample without contamination. 

If a comparison of urine drug or biomarker over time is needed, the 24-hour urine collection method is the preferred method.

It is important to note that all urine collection methods should be done following standard precautions to ensure sample integrity and accuracy of results.

Depending on the research question and laboratory costs, there is a cost difference between the types of urine collection. Immediate collection methods such as urethral catheterization and suprapubic aspiration are more expensive than the 24-hour urine collection method. 

This is largely due to the costs associated with collecting and processing the sample. Additionally, due to the time involved in collecting a 24-hour urine sample, the cost of time spent collecting and shipping the sample should also be taken into consideration.

While many research protocols call for utilizing urine specimens alone, there is utility in incorporating additional biospecimens – such as blood, saliva, and stool – into clinical research studies. 

Combining different biospecimens as part of a research study can provide a more complete picture of the biological processes being studied. This is especially true for studies involving biomarkers, which often require multiple biospecimens that can serve as surrogates to extrapolatory information.

Where To Obtain Urine Specimens

Obtaining urine specimens for clinical research can be done in real-time at study visits, or they can be obtained from specialized biobanks or biorepositories. Depending on the research at hand, acquiring enough useful, high-quality urine specimens can be a difficult task.

Clinical research organizations (CROs) have become a popular choice for obtaining biospecimens. With the rise of CROs and their abundance of resources, organizations have been able to utilize these services to gain access to a variety of high-quality biospecimens. 

CROs are able to provide the necessary infrastructure and equipment to obtain, store, and manage biospecimens from clinical trials in a compliant manner. In addition, CROs can provide access to specialized personnel and expertise to ensure that samples are handled and stored properly.

Ultimately, choosing the right urine specimen collection method can make a dramatic difference in the success of a clinical trial. 

At iProcess Global Research, you can expect to work with a team of experts in clinical trial design with years of experience obtaining biospecimens from all over the world. Working with iProcess can help ensure a clinical trial’s success.

Contacting iProcess is quick and easy. Request a free quote today.

Sources:

Urinalysis – StatPearls – NCBI Bookshelf

Best methods for urine sample collection for diagnostic accuracy in women with urinary tract infection symptoms: a systematic review | PMC

Contamination rates of different urine collection methods for the diagnosis of urinary tract infections in young children: an observational cohort study | PMC