The value of examining a patient's urine has been known since ancient times. Medieval physicians went nowhere without their beakers to collect urine specimens. At that time, there was only a basic idea of what could be derived from such study. As technology has advanced, the humble specimen has yielded more information. Today, collecting important data from urine is faster, more precise and easier than ever before.
There are many reasons a patient's urine is examined. For the diagnosis of diseases, as a general marker of good health, to check for foreign substances and as a monitor of treatments. The classification of urine specimens is determined by the manner in which a specimen is collected. Each test is tailored and conducted to obtain specific types of information. Therefore, it is most important that the proper procedure is carried out for the particular type of urinalysis ordered. The failure to accurately follow protocol in the collection of urine specimens can lead to faulty calculations. This has the potential to result in misdiagnosis or incorrect treatment modalities.
The random specimen is the type that is most commonly ordered, due to its ease of collection. The specimen can be collected at any time that is convenient for the patient. A sterile procedure is not followed in such cases. However, the avoidance of contamination should include simple patient instruction. Have the patient wash his hands prior to voiding; instruct him to pass a small amount of urine before collecting their sample, and reiterate the importance of not touching the inside of the specimen cup, including the lid. The patient should also be reminded to return the specimen in a timely manner.
First morning specimen
The first morning specimin is sometimes called an eight-hour specimen. This type is generally used to determine the levels of cellular elements and analytes present. The patient should be instructed to urinate before going to bed at night. The bladder should then be emptied on rising from bed, and the urine is collected at that time. It is important for the patient to follow clean technique to avoid gross contamination of the specimen. If it is not possible for the patient to hold his urine for eight hours, any urine passed should be collected, refrigerated and added to the urine collected in the morning.
Clean catch specimen
A clean-catch specimen is is also referred to as a midstream specimen. A clean catch specimen is commonly used for bacterial culture and sensitivity. It is important that the patient understands the procedure of the collection process. The patient should be given a sterile collection cup and cleansing towelettes. After washing her hands, the patient opens the sterile cup with the lid placed upside down beside it. Using the towelettes, the patient should clean the area around the urethral opening, wiping from front to back. This should be repeated two more times. The first portion of urine should be voided into the toilet or another container. At approximately the middle of the urine flow, the container should be placed to obtain the specimen. The remainder of urine should be voided into the toilet. The specimen cup should be handled and re-capped carefully to avoid contamination.
Timed specimens are also known as 24-hour specimens. These types of samples are collected to measure the concentration of specific electrolytes, such as potassium, glucose and sodium. Additionally, the levels of urea, nitrogen, creatinine and catecholamines, are measured. The patient should be instructed to void at the beginning and at the conclusion of the study. The patient then collects and pools all urine within that 24-hour period. The urine should be kept refrigerated in a special container used for this purpose. It is important for the patient to keep an accurate record of the time, as this will effect the final analysis.
Also known as sterile specimens, this procedure is done by a qualified health care worker. This is done in cases where a patient can not urinate independently, or if an indwelling (foley) catheter is already present. Strict sterile procedure is followed during the catherization. A tube is inserted into the bladder through the urethra and the urine is collected in a sterile container. In patients where a catheter is already present, the specimen is collected either through an evacuated tube or a syringe.
Obtaining a urine specimen in children or infants requires parents or caregivers who are able and willing to follow protocol to ensure accurate results. In some cases the catheterization of a child may be the best approach, though it is the most invasive option. The collection of a specimen using supra-pubic aspiration is sometimes employed. This involves inserting a needle through the abdominal wall and into the bladder in order to obtain the specimen. The least traumatic and simplest method is the application of a urine collection bag. After cleansing the area around the urethral opening, a bag is attached to the area using gentle adhesive strips. The drawback of this method is the necessity of frequent bag changes.