Urinalysis

What is Urinalysis?

A urinalysis is a panel, not a single test.

A urinalysis isn't one measurement. It's three examinations of the same sample, printed on one report: how the urine looks, what a chemical strip reads, and what shows up under a microscope. Labcorp's "Urinalysis, Complete With Microscopic Examination" lists twelve lines (color, appearance, specific gravity, pH, protein, glucose, occult blood, ketones, leukocyte esterase, nitrite, bilirubin, and urobilinogen) plus microscopy of the urine sediment. Knowing which examination produced a line tells you how much weight a single line can carry. The first examination is by eye. Color and clarity are described in words. Specific gravity compares the density of your urine with water, so it's a unitless ratio printed to three decimals, and pH is a scale number. A dipstick pad can estimate specific gravity quickly, though MedlinePlus notes that a lab measurement can be more precise. The second examination is the dipstick. Each pad changes color when a substance is present, and the lab reports the result as negative or as a graded amount. The pads cover protein, glucose, ketones, bilirubin, urobilinogen, blood, nitrite, and leukocyte esterase. Each pad measures something narrower than its name suggests. According to StatPearls, the blood pad reacts to peroxidase activity from red blood cells, hemoglobin, and myoglobin, so it can't tell those apart without microscopy. The ketone pad detects acetoacetic acid and acetone but not beta-hydroxybutyrate. The nitrite pad only picks up bacteria that carry the enzyme nitrate reductase, and leukocyte esterase can't detect lymphocytes. The third examination is microscopy. The lab concentrates the sample, looks at the sediment, and counts red cells and white cells per high-power field (hpf), casts per low-power field (lpf), and squamous epithelial cells. It also notes crystals and bacteria. Mayo Clinic adds yeast and parasites to the list of things a technologist looks for. These counts are a different kind of data from dipstick colors, which is why one report can contain both a dipstick line and a microscopy line that don't line up. Collection changes what the lab sees. Mayo Clinic describes the clean-catch method: cleanse the urinary opening, start urinating into the toilet, move the container into the stream, then finish in the toilet. It also says a first-morning sample is more concentrated, and that the sample should reach the lab within 60 minutes or be refrigerated. Sources don't agree on volume (Mayo Clinic says at least 1 to 2 ounces, or 30 to 60 milliliters; StatPearls says 15 to 30 mL), so the instructions on your lab's container win. Cleansing itself is debated: StatPearls notes that many facilities no longer perform it routinely, while Labcorp says a clean-catch midstream sample is desirable when contamination is likely. Contamination matters because StatPearls lists contamination as a cause of false-positive leukocyte esterase, and bacterial overgrowth in a sample that sits too long can produce false-positive blood reactions and change the pH. A dipstick isn't a culture, and that's the most useful distinction on this page. A culture grows bacteria from the sample and counts them. The Infectious Diseases Society of America (IDSA) defines asymptomatic bacteriuria by a culture count of at least 10^5 colony-forming units per milliliter in a voided specimen, in a person without symptoms of infection. A strip can't produce that number. In a June 2026 study of 199 adults aged 60 and older with suspected urinary tract infection, a positive nitrite or leukocyte esterase of 1+ or more had 93.6% sensitivity and 58.6% specificity against a consensus reference standard. The authors called that high sensitivity but poor specificity. Raising the cutoff to a combined 2+ gave 82.2% and 75.7%. Screening is a separate question from testing. The US Preventive Services Task Force (USPSTF) reviewed screening for bacteriuria with urine culture in 2019. It recommends screening in pregnancy (grade B) and recommends against it in adults who aren't pregnant (grade D). IDSA's 2019 guideline also advises against screening for or treating asymptomatic bacteriuria in healthy premenopausal women, people with diabetes, functionally impaired older adults living in the community, and long-term care residents, and it supports screening and treatment in pregnancy. Both statements concern bacteriuria screening. They don't speak to every reason a clinician orders a urinalysis. Longetic doesn't perform or interpret this test. You upload the report from any clinic in any format, and each line stays organized and searchable next to the range the lab printed.

Typical reference context

These are the values two published references print as typical, not a verdict on any sample. Notice that the two sources disagree on the edges of specific gravity and pH, and MedlinePlus states that ranges vary slightly among labs and that some labs use different measurements. The range printed on your own report is the one that applies to your result.

What changed recently

Nothing has changed in the screening position itself. As of October 2026, the USPSTF page for asymptomatic bacteriuria still shows the September 24, 2019 statement, with no update notice, and the IDSA asymptomatic bacteriuria guideline cited here is still the 2019 update. The newer work is about how well the pieces perform.

A 2026 systematic review and meta-analysis in Diagnostics (Chang and colleagues, April 23, 2026) pooled 18 studies and 25,337 samples on the Sysmex UF-5000, an automated fluorescence flow cytometer that counts cells and bacteria in urine. Against urine culture, the pooled bacterial count had 0.927 sensitivity (95% CI 0.872 to 0.959) and 0.751 specificity (95% CI 0.558 to 0.878). The authors report substantial heterogeneity across studies, and say the instrument can't identify the organism or distinguish contamination from true infection.

The June 2026 BMC Geriatrics study (Baart and colleagues) is the dipstick evidence above. In July 2025, IDSA also published a guideline on complicated urinary tract infections, which covers treatment in patients with features such as catheters or obstruction and suggests choosing definitive antibiotics based on urine culture results. A 2023 review of an academic hospital's urinalysis-to-culture reflex orders (Keintz and colleagues) found that 839 of 9,493 reflexed cultures used an "other" indication and that 97% of those were judged inappropriate. That's a hospital stewardship finding, not a change to what the lab measures.

Tests often checked alongside this

A urinalysis is often one of several tests on a visit, and the urine culture, which grows and counts bacteria, is the usual companion when a clinician wants more than the dipstick can give. Kidney topics overlap with this panel, since urine protein and blood show up on a dipstick, but kidney function is described from blood work: see Creatinine and Estimated Glomerular Filtration Rate (eGFR) for what those values measure.

What can affect a urinalysis result

Several everyday things change a line without changing anything about you. StatPearls lists rifampin, nitrofurantoin, beets, and rhubarb as altering urine color, and says exercise alters specific gravity. High vitamin C intake can produce false-negative nitrite and glucose results (Labcorp). Light and temperature degrade bilirubin and urobilinogen in a sample that sits, and some preservatives interfere with specific pads. Mayo Clinic advises telling your doctor about everything you take, because medications, vitamins, and supplements can affect the results.

What to keep alongside each report

One urinalysis is a snapshot of one sample on one day. Labs print different ranges, and some report protein per day while others use mg/dL, so a number is only comparable to another number from the same lab and the same kind of sample. When you file a report, keep the collection date, whether it was a first-morning, random, or clean-catch sample, and the range the lab printed beside each line.

What to ask your doctor

• Which lines on this report came from the dipstick and which from the microscope?
• Was my sample a clean-catch, first-morning, or random one, and did that matter for this panel?
• Was a culture ordered, and if not, what would make you order one?
• Could any of my medications, vitamins, or foods have affected a line on this report?

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