Urinalysis Test
Overview
Urinalysis, or UA, is a common test used to evaluate urine’s appearance, concentration, and contents. A dipstick urinalysis can quickly detect signs of infection, kidney disease, diabetes, and other health issues.
Changes such as cloudy urine or excess protein may indicate an underlying problem. If results appear abnormal, doctors may order additional tests for further evaluation.
Reasons for Performing the Test
Urinalysis serves several purposes in healthcare. It helps assess general health, diagnose medical conditions, and monitor ongoing illnesses. Common reasons for urinalysis include:
- Routine Health Screening: Doctors may include urinalysis in annual checkups or pre-surgical evaluations to detect early signs of conditions like diabetes, kidney disease, or liver disease—often before symptoms appear.
- Symptom Diagnosis: When someone experiences symptoms such as lower abdominal pain, back pain, painful urination, or blood in the urine, a urinalysis can help identify problems with the kidneys, bladder, or urinary tract.
- Monitoring Chronic Conditions: For individuals with diagnosed conditions like kidney disease or diabetes, regular urinalysis helps evaluate treatment effectiveness and detect early complications such as infections or declining kidney function.
- Metabolic Disorder Detection: Certain diseases cause abnormal chemicals to appear in urine. Urinalysis can assist in diagnosing and managing metabolic conditions such as diabetic ketoacidosis, renal tubular acidosis, and glomerulonephritis.
Below is a summary table showing why urinalysis is requested:
| Reason | Examples |
|---|---|
| Routine screening | Diabetes, liver disease, kidney screening |
| Symptom investigation | Urinary tract infection, hematuria, back pain |
| Monitoring treatment | Chronic kidney disease, diabetes, glomerulonephritis |
| Metabolic disorder check | Renal tubular acidosis, diabetic ketoacidosis |
How You Prepare
To get ready for a urine test, a person can usually eat and drink as normal unless told otherwise for other tests. Staying well-hydrated is important, but large amounts of water should be avoided to prevent diluting the urine.
Be sure to tell the health care provider about any medicines, vitamins, or supplements currently used. If instructed by the clinic, refrigerated urine samples may also be acceptable.
What Happens During Urine Sample Collection
Most people collect a urine specimen either at home or at a clinic, often after receiving a special container from their provider. For accurate results, the first urine of the day is sometimes preferred because it is more concentrated.
Providers may recommend using the clean-catch technique to minimize contamination. Below is a simple checklist of the typical clean-catch procedure:
| Step | Instructions |
|---|---|
| 1 | Wash hands thoroughly. |
| 2 | Clean around the urethra (urinary opening). Women should clean from front to back, and men should clean the tip of the penis. |
| 3 | Start urinating into the toilet. |
| 4 | Move the collection cup into the urine stream midstream. |
| 5 | Collect about 1 to 2 ounces (30–60 mL). |
| 6 | Finish urinating into the toilet. |
| 7 | Seal the container and deliver it as instructed. |
If you cannot drop off the sample within one hour, refrigerate it as instructed. In certain situations, a health professional might need to use special methods to get a urine sample.
These may include manual bladder expression, cystocentesis (using a needle directly into the bladder), or a catheter passed through the urethra. After collecting the urine specimen, the lab staff observe and test it. Most people can return to normal activities right away.
Findings from Urine Testing
Visual Assessment
The first step in urine testing involves a direct look at the urine’s appearance. Healthy urine is usually pale yellow and clear. Cloudiness might suggest conditions such as infection, an increase of white blood cells, or precipitation of phosphate crystals.
A strong or unusual smell can also point toward infection or high concentrations of certain substances. Changes in color may hint at various health issues or simply be the result of recent foods, such as beets or some medications.
Red or brown hues could signal blood in the urine, also known as hematuria, which might indicate kidney problems, stones, inflammation, or injury. Foamy urine can be a sign of proteinuria, where excess protein appears in the urine, possibly reflecting kidney impairment.
Key Visual Indicators
| Appearance | Possible Cause |
|---|---|
| Cloudy | Infection, pyuria, crystals |
| Red/Brown | Blood, some foods/drugs |
| Foamy | High protein levels |
| Unusual odor | Bacterial contamination, infection |
| Yellow/Amber | Normal urine color |
Chemical Strip Analysis
A chemical analysis uses a special urine dipstick, which reacts to different substances in the urine. Each patch on the strip turns color based on the chemical content, giving rapid clues about several possible health issues.
| Substance | Normal Range | What It Can Show When Abnormal |
|---|---|---|
| pH | 4.5-8.0 | UTI, kidney issues, diet changes |
| Specific Gravity | 1.005-1.030 | Dehydration, kidney function, osmolality |
| Protein | Negative/trace | Kidney impairment, infection |
| Glucose | Negative | Diabetes, high blood sugar |
| Ketones | Negative | Diabetes, fasting, metabolism problems |
| Bilirubin | Negative | Liver disease, hemolysis |
| Nitrites | Negative | Bacterial infection |
| Leukocyte Esterase | Negative | White blood cells, infection, inflammation |
| Blood | Negative | Injury, stones, infection, cancer, trauma |
- Urine pH (Acidity): Measures how acidic or basic the urine is. Typical urine pH ranges from 4.5 to 8.0. Out-of-range values can be associated with kidney disorders or metabolic imbalances.
- Specific Gravity: This test reveals how concentrated the urine is. A high specific gravity often means dehydration, while a low value might point to kidney dysfunction.
- Protein: While trace amounts are normal, notable protein presence (proteinuria) can suggest kidney disease or increased glomerular permeability.
- Glucose (Glycosuria): Glucose in urine is usually very low; detectable sugar may indicate diabetes or other metabolic issues.
- Ketones: Ketone bodies are not normally present. Their detection can be due to diabetes, starvation, or metabolic stress.
- Bilirubin & Urobilinogen: These substances result from the breakdown of red blood cells. Their presence might be linked to liver problems or hemolysis.
- Nitrates & Leukocyte Esterase: Nitrites, formed by some bacteria, and leukocyte esterase, produced by white blood cells, can be markers of a urinary tract infection.
- Blood: The finding of blood, or microhematuria, may point to kidney stones, infections, inflammation, or tumors.
Examination Under the Microscope
The microscopic part of the urinalysis investigates cell elements, organisms, and crystals that are invisible to the naked eye. Laboratory staff study drops of centrifuged urine on glass slides.
- White Blood Cells (Leukocytes): High amounts indicate inflammation or infection within the urinary tract, manifesting as pyuria.
- Red Blood Cells: Their presence (either visible or microscopic) can indicate sources of bleeding—such as stones, urinary tract infection, trauma, tumors, or glomerular diseases (as seen in nephritis).
- Bacteria, Yeast, or Parasites: These microorganisms suggest an ongoing infection or contamination.
- Epithelial Cells: Small numbers are normal, but increased amounts may hint at tubular injury, infection, or contamination.
- Casts: Proteins form these tube-shaped particles, which may encase cells. The appearance of red cell or white cell casts signals underlying kidney disease.
- Crystals: Identifiable shapes can point to types of kidney stones, metabolic illnesses, or be normal. Abnormal crystals, such as uric acid or cystine, may help in diagnosing metabolic problems.
- Amorphous Crystals: These commonly appear and are usually harmless, but sometimes may reflect changes in urine pH.
