Learning Objectives
By the end of this section, you will be able to:
- Describe the physical, chemical, and microscopic characteristics of urine
- Verbalize the steps in collecting a urine specimen
- Interpret the results of a urine analysis
Clinical nursing practice relies on the comprehensive understanding of urine specimens, encompassing the physical, chemical, and microscopic features of this diagnostic testing. This information is vital for identifying potential health issues, conducting accurate assessments, providing effective patient care, and developing treatment plans based on the specific characteristics observed in the urine samples. This chapter not only explores these fundamental characteristics but also guides you through the meticulous process of urine specimen collection, emphasizing the importance of precise technique and patient-centered care. Equally vital is the skill of interpreting urine analysis results, which enables nurses to translate findings into actionable insights for optimal patient care.
Urinalysis Overview
A complete urinalysis examines the physical, chemical, and microscopic composition of a sample of urine. A visual analysis of the urine describes the physical appearance of the urine. Physical characteristics include the color and turbidity (cloudiness) as well as the presence or absence of particles and the odor.
Chemical analysis of the urine involves placing a special test strip, called a dipstick, into the urine. The dipstick contains chemically infused pads on the strip that change color when certain substances are present in the urine. The color on the dipstick is compared with a color table that was provided with the test packaging that indicates what the different colors on the dipstick mean. Dipstick testing can be used to assess the pH level (acid-base level), urine specific gravity (concentration of solutes), as well as a variety of substances in the urine, such as protein (such as albumin), ketones (spill into urine when the body has to break down fats for energy), glucose (sugar), bilirubin (yellow pigment produced by the liver that is found in bile), nitrites (indicative of bacterial presence), and leukocyte esterase (white blood cells).
Microscopic analysis of the urine involves looking at drops of concentrated urine under a microscope to evaluate the presence of various cellular and noncellular components. It can be used to see if there are physical traces of foreign particles, such as crystals, bacteria, yeast, red or white blood cells, or urinary casts (small particles shaped like a tube that may contain different types of cells or substances). The microscopic analysis is typically performed in conjunction with a routine urinalysis, which includes the physical and chemical tests.
Purpose
A urinalysis is a valuable diagnostic tool for healthcare professionals to assess various aspects of health, including monitoring of certain health conditions (such as diabetes, kidney disease, and liver disease) and diagnosing urinary tract infections. Gradual changes in urine composition over time or big jumps to values outside of the normal ranges are potential cues that can alert the provider to further investigate the body systems and how they are working.
Types of Urine Collection
There are several types of urine sample collection methods, each suited to specific purposes or medical requirements. The choice of method depends on the clinical or diagnostic need. The following are common types of urine sample collections:
- A clean-catch urine sample is the most common method of urine collection. The patient is asked to start urinating into the toilet, stop briefly, and then continue urinating into the container. This is done to avoid contamination of the sample with initial stream urine and any bacteria around the urethral opening. It is often used for routine urinalysis, culture and sensitivity testing, and other general diagnostic purposes.
- A twenty-four-hour urine collection involves collecting all urine produced over a twenty-four-hour period. The collection typically starts after the first voided morning urine and ends with the first voided morning urine on the following day. It is used for tests that require measurement of substances excreted over an extended period, such as creatinine clearance, protein excretion, or hormone levels.
- The first morning void (FMV) sample is used for some tests. The first urine voided in the morning is usually more concentrated, making it suitable for some specific tests, such as pregnancy tests and for monitoring hormone levels.
- A timed urine collection may be ordered. For this, urine is collected at specific times throughout the day, typically for several hours or even a full day. It is used for tests that require monitoring of substances or metabolites at different points in time, such as glucose tolerance tests.
- To obtain a catheterized urine sample, a catheter is inserted into the bladder to obtain a urine sample directly from the bladder. This method is employed when a clean sample is necessary, especially if the person cannot provide one through normal voiding, such as in cases of urinary retention or surgery.
- The method of suprapubic aspiration is invasive and involves using a needle and syringe to aspirate urine directly from the bladder through the abdominal wall. It is used in specific cases where other methods are not feasible or sterile samples are required, such as in infants or when a catheter cannot be used.
- A pediatric collection device may be used. For infants and young children who are not yet toilet-trained, a urine collection bag or adhesive pediatric collection device can be used. These devices adhere to the child’s genital area to collect urine. Care must be taken to ensure a clean and uncontaminated sample.
- A random urine sample is collected at any time without specific timing or preparation. It can be used for a variety of tests but is often less reliable compared to clean-catch or timed samples.
Link to Learning
How to collect a urine sample from an indwelling Foley catheter is demonstrated in this video.
Clinical Safety and Procedures (QSEN)
QSEN Competency: Obtaining a Urine Specimen from a Foley Catheter
See the competency checklist for Obtaining a Urine Specimen from a Foley Catheter. You can find the checklists on the Student resources tab of your book page on openstax.org.
Procedural Steps for Urine Collection
To collect a clean-catch or midstream urine sample, you need a sterile urine collection container and facility-approved antiseptic wipes or antiseptic solution. Start by washing your hands thoroughly with soap and water to prevent contamination of the sample. Identify the patient with name and date of birth, matching with patient verbally and checking ID bands. Preprinted labels should be verified too. Don gloves and prepare the collection container by opening the collection container lid. Use caution not to touch the inside of the container or the lid, as the inside of the container and lid should remain sterile. Set the container aside in a clean, convenient location, using caution that the inside of the lid does not touch any surface.
Ensure patient privacy and explain the procedure to the patient. Prepare the patient by cleaning the genitalia, which helps reduce the risk of contamination from the surrounding skin. If the patient has a vagina, spread the labia with your nondominant hand. With your dominant hand, cleanse the genital area using a facility-approved antiseptic wipe and wiping from front to back to prevent bacteria from entering the urinary meatus. Use one wipe to clean the right side of the genitalia, one wipe to clean the left side of the genitalia, and one wipe to clean down the middle. If the patient has a penis, use a circular motion to cleanse the tip of the penis, starting at the urinary meatus and working away from the urinary meatus. If the patient is not circumcised, retract the foreskin prior to cleansing the penis.
Before collecting the sample, ask the patient to urinate a small amount into the toilet to clear any potential contaminants from the urethra. Ask the patient to stop the urine stream and then hold the urine collection container in one hand and gently spread the labia for women or retract the foreskin for men to expose the urethral opening. Instruct the patient to restart the urine stream into the sterile container. Collect enough urine to fill the container to the level indicated on the collection container, which is typically around 30 to 60 mL or as specified. Instruct the patient to finish urinating into the toilet if needed, and then carefully cap the collection container without touching the inside of the lid. Label the collection container with the patient’s name, date, time collected, and any other requested information according to facility. After sealing the container, place the collection container in a biohazardous lab specimen bag, and wash your hands thoroughly again to ensure hygiene. Deliver the sealed urine sample container to the laboratory as instructed. The sample should be sent promptly to the lab or stored according to facility protocol if immediate testing is not possible.
Link to Learning
Learn how to collect a clean-catch urine sample in this video demonstration.
To perform a twenty-four-hour urine sample, the nurse will collect all urine produced by the patient for twenty-four hours. Typically, twenty-four-hour urine samples are started in the morning upon waking up. Instruct the patient to urinate upon waking up and discard the first morning urine. Note the exact time of the first morning urine, as this is the start time for the twenty-four-hour collection period. To ensure accurate results, it is crucial to document the start time of the twenty-four-hour collection period as well as the end time for the testing. Collect all urine passed for the next twenty-four hours, ensuring every drop of urine during this time is included in the collection.
Clinical Safety and Procedures (QSEN)
QSEN Competency: Collecting a Twenty-Four-Hour Urine Specimen
See the competency checklist for Collecting a Twenty-Four-Hour Urine Specimen. You can find the checklists on the Student resources tab of your book page on openstax.org.
To collect the urine, the patient will void into a clean, plastic collection container that fits under the toilet seat (or a clean urinal may be used). The urine from the collection container or urinal will then be poured into a large, plastic container (Figure 10.2). It is important to collect all urine throughout the twenty-four hours, being careful that no urine spills. It is essential to avoid any contamination with water, toilet paper, bowel movements, or other foreign substances, as contamination may impact the test results. The twenty-four-hour urine container should be kept cold throughout the twenty-four-hour window. Typically, the container is put on ice at the patient’s bedside in healthcare settings. It is critical to replace the ice as necessary to ensure the urine remains cold. If the twenty-four-hour urine container fills up, keep the full container on ice and obtain another container from the laboratory. Once the twenty-four-hour marker has been reached, instruct the patient to void one last time, adding the urine to the collection container. Clearly label the container with the patient’s name, date of birth, start and end times of the collection, and any other information requested by the facility’s policies. Transport the sample to the lab as soon as possible for accurate results, ensuring the sample remains cold during transport.
Documentation of Urine Collection
Proper documentation of urine collection is a crucial aspect of patient care, as it helps maintain the integrity of samples, ensures patient safety, and provides a clear record of the collection process for future reference. It also aids in tracking and tracing samples in case of any issues or disputes. For instance, accurate recording of the start and end times is crucial when a patient is undergoing a twenty-four-hour urine collection to assess kidney function. In cases where there may be concerns or disputes about the collected sample, perhaps the start and end times are not noted on the sample container, detailed documentation can become a valuable reference for tracking and tracing the collection times. The first step of documentation is to verify the patient’s identity by checking their identification band and asking for their name and date of birth to verify the sample was collected from the correct patient. Document the date and time of urine collection, type of urine sample collected (e.g., clean-catch sample, twenty-four-hour collection), any relevant patient information (e.g., patient’s complaints or symptoms), and special instructions or comments (if applicable). Some electronic medical record systems may have specific forms or templates for urine collection documentation.
Document the transfer of samples to the laboratory, if required. If the sample needs to be stored before testing or if there are specific storage requirements, document these instructions clearly in the medical record as well. Document any unexpected events, deviations from the standard procedure, or patient reactions during the urine collection process. Before leaving the patient or completing the documentation, review all the information to ensure accuracy and completeness. Ensure that all documentation complies with institutional, legal, and privacy regulations governing healthcare records.
Patient Education
Patient education is a critical component when performing a urine sample collection. Providing clear and thorough instructions to the patient helps ensure the accuracy and reliability of the sample and contributes to a positive patient experience. Be sure to include the following:
- Explain why the urine sample is necessary.
- Note the specific type of urine sample required (e.g., clean-catch sample, twenty-four-hour collection) and why it is needed for the patient’s diagnosis or treatment.
- Describe the collection procedure and what they can expect throughout the process. If the patient will be collecting the urine sample independently, additional instructions will be needed to ensure the patient can accurately perform the procedure.
Encourage the patient to ask questions if they have any doubts or concerns. Make sure they understand the instructions fully before they start the collection. If necessary, explain when and how the patient will receive the results of the urine sample and any subsequent actions required. Offer written instructions or a handout summarizing the key points for the patient to reference as needed.
Clear and patient-centered communication is essential in ensuring that the patient understands the urine sample collection process, which, in turn, enhances the quality and reliability of the sample. It also contributes to a positive patient experience and cooperation during the procedure.
Interpretation of Results
Interpreting a urine analysis involves analyzing the results of various tests performed on a urine sample to assess a person’s health. The interpretation of urinalysis results can provide valuable insights into various aspects of an individual’s health, including kidney function, hydration status, and the presence of certain medical conditions. To correctly interpret the results, the nurse must be aware of normal findings, abnormal findings, and factors that affect the results.
Normal Findings
Normal urine is yellow, clear, and has a mild odor. Other normal findings of a urinalysis are listed in Table 10.1. While these findings are considered “normal,” it is important to note that urine composition can vary among individuals based on factors such as age, diet, hydration status, and overall health. What may be considered “normal” for urine findings in one age group or life stage may differ from another. For example, infants may have different norms for urine color and chemical content compared to adults. Additionally, changes in kidney function, metabolism, and other physiological factors associated with aging can impact urine characteristics in older adults. Health conditions more common in certain age groups may also influence urine test results. As a result, healthcare professionals take these variations into account when interpreting urine findings, recognizing that what is considered normal can differ across different age groups and life stages.
| Physical Examination | |
| Color | Yellow (light/pale yellow to amber) |
| Turbidity | Clear |
| Odor | Mild, slightly ammonia-like odor |
| Chemical Examination | |
| pH | 4.5 to 8.0 (pH of 7 is neutral, >7 is alkaline, <7 is acidic) |
| Specific gravity | 1.005 to 1.030 |
| Glucose | Negative |
| Blood | Negative |
| Ketones | Negative |
| Protein | Less than or equal to 150 mg/day or 10 mg/dL |
| Urobilinogen | 0.1 mg/dL to 1 mg/dL in random samples or up to 4 mg/daily |
| Bilirubin | Negative |
| Nitrites | Negative |
| Leukocyte esterase | Negative |
| Microscopic Examination | |
| Red blood cells | Zero to five cells/high-power field |
| White blood cells | Zero to five cells/high-power field |
| Eosinophils | Absent |
| Squamous epithelial cells | Less than or equal to fifteen to twenty cells/high-power field |
| Crystals | Absent |
| Bacteria, fungi, yeast, or parasites | Absent |
| Casts | Absent |
Abnormal Findings
Abnormal findings include urine that is colorless, red, orange, dark yellow, or brown, cloudy, or foul smelling. Other abnormal findings are listed in Table 10.2.
| Physical Examination | |
| Color | Colorless (indicates diluted sample), red (may be secondary to blood, certain foods, or medications), blue or green (may be secondary to certain foods, medications, or bacteria), orange (may be secondary to bile pigments, certain foods, or medications), dark yellow (concentrated sample, may indicate dehydration), or dark brown/tea colored (may be secondary to bile, certain foods, or medications) |
| Turbidity | Cloudy (indicates the presence of suspended particles, such as cells, crystals, or bacteria) |
| Odor | Foul (may indicate infection), fruity (may indicate diabetic ketosis), strong (may indicate dehydration), fecal (may indicate fistula) |
| Chemical Examination | |
| pH | Less than 4.5 (acidic; may indicate dehydration, diabetes, diarrhea) or greater than 8 (alkaline; may indicate old sample, hyperventilation, vomiting) |
| Specific gravity | Less than 1.005 (may indicate the urine is dilute/too much water) or greater than 1.030 (may indicate the urine is concentrated/not enough water) |
| Glucose | Greater than 1,000 mg/dL (may indicate diabetes, gestational diabetes, Cushing syndrome) |
| Blood | Present (may indicate kidney issues or muscle trauma) |
| Ketones | Present (may indicate uncontrolled diabetes, pregnancy, starvation) |
| Protein | Greater than 150 mg/day, or 10 mg/dL (may indicate congestive heart failure, strenuous exercise, kidney or pregnancy issues, or fever) |
| Urobilinogen | Less than 0.1 mg/dL or greater than 1 mg/dL in random samples, or greater than 4 mg/daily (may indicate liver disease, antibiotic use) |
| Bilirubin | Present (may indicate liver dysfunction) |
| Nitrites | Present (may indicate urinary tract infection [UTI]) |
| Leukocyte esterase | Present (may indicate inflammation) |
| Microscopic Examination | |
| Red blood cells | Greater than zero to five cells/high-power field (may indicate UTI or inflammation) |
| White blood cells | Greater than zero to five cells/high-power field (may indicate UTI or inflammation) |
| Eosinophils | Present (may indicate UTI or kidney issues) |
| Squamous epithelial cells | Greater than fifteen to twenty cells/high-power field (may indicate contamination, UTI) |
| Crystals | Present (may indicate acidic or alkaline urine, decreased urine output) |
| Bacteria, fungi, yeast, or parasites | Present (may indicate contamination, UTI) |
| Casts | Present (may indicate various kidney disorders) |
Factors Affecting Results
Urinalysis results may be affected by a variety of factors, including diet, medications, medical conditions, and contamination. What an individual eats and drinks can impact urine composition (Table 10.3).
| Factor | Alteration of Urinalysis |
|---|---|
| Dehydration | Concentrated urine, affects specific gravity |
| Extended exposure to light | Decomposes urobilinogen and bilirubin |
| Extended periods at room temperature | Encourages bacterial growth |
| Contamination | False-positive infection or alters pH level |
| Alkaline pH | False positive for protein |
| Glucose | Decrease in the sample pH |
| Contrast | False-positive specific gravity |
| Certain foods and drugs (including food coloring, blackberries, red beets, rhubarb, phenytoin, rifampicin, ibuprofen, chloroquine, deferoxamine, nitrofurantoin, metronidazole, phenolphthalein, phenothiazines, and imipenem/cilastatin) |
Alterations in urine color, odor, or pH value |
Other factors that affect urinalysis results include exercise, menstrual cycles, and pregnancy. Vigorous physical activity can lead to dehydration, which may affect urine concentration. For persons with ovaries, menstrual blood can sometimes contaminate a urine sample, causing false-positive results for hematuria, or blood in the urine. Pregnancy can affect urine composition, leading to changes in protein levels, glucose, and other parameters.
There are also factors associated with the collection procedure to consider. Urine composition can vary throughout the day. For example, the first morning urine sample may be more concentrated, while urine collected later in the day may be more dilute. Proper collection techniques may also impact the results. For example, the results of a twenty-four-hour urine collection may be impacted by forgetting to collect all of the urine, going beyond the twenty-four-hour time limit, losing some of the urine due to spilling or overflow, or not keeping the urine cold. Proper handling and storage of the urine sample are crucial. To ensure accurate urinalysis results, it is essential to consider these factors and take them into account when interpreting the data. Additionally, healthcare providers may use a combination of tests and clinical information to arrive at a comprehensive diagnosis when evaluating a patient’s health based on urinalysis results.