How to Read UTI Test Strips: A Step-by-Step Guide
Cheeky Bonsai Team
How to Read UTI Test Strips Without the Guesswork
You've got the burning, the urgency, and the "is this a UTI or am I just dehydrated?" internal debate happening. Before you spiral, there's a simple way to get answers at home: UTI test strips. But knowing how to read UTI test strips correctly is just as important as having them on hand. A misread result can mean unnecessary panic — or worse, ignoring an infection that needs treatment.
At-home UTI test strips are quick, affordable, and surprisingly accurate when used properly. They're the same type of dipstick tests that many doctors' offices use for initial UTI screening. In this guide, we'll walk you through exactly what these strips measure, how to use them step by step, how to interpret the color changes, and what to do with your results.
What Do UTI Test Strips Actually Measure?
Most at-home UTI test strips, including Cheeky Bonsai's UTI Test Strips, measure two key biomarkers in your urine that indicate the presence of a urinary tract infection.
Leukocytes (White Blood Cells)
Leukocytes are white blood cells — your immune system's first responders. When bacteria invade your urinary tract, your body sends white blood cells to fight the infection. Elevated leukocytes in your urine (a condition called leukocyturia) suggest that your body is actively fighting an infection or inflammation in the urinary tract.
The leukocyte test pad on your strip detects an enzyme called leukocyte esterase, which is released by white blood cells. A positive result means white blood cells are present in your urine, which is a strong indicator of infection or inflammation.
Nitrites
Nitrites are a chemical byproduct produced when certain bacteria — most notably E. coli — convert nitrates (which are naturally present in your urine from your diet) into nitrites. Healthy urine doesn't contain nitrites, so a positive nitrite result is a strong indicator that bacteria are present in your urinary tract.
Important to know: not all UTI-causing bacteria produce nitrites. Some bacteria (like Staphylococcus saprophyticus and Enterococcus) don't convert nitrates to nitrites, which means you can have a UTI with a negative nitrite result. That's why testing for both markers is essential.
How to Use UTI Test Strips: Step-by-Step
Getting an accurate result starts with proper technique. Here's exactly how to do it.
Step 1: Gather Your Supplies
You'll need your UTI test strips, a clean container to collect urine (or you can use the midstream technique directly), and a timer on your phone. Make sure the test strips haven't expired — the expiration date is printed on the packaging.
Step 2: Collect a Midstream Urine Sample
Timing matters. First morning urine gives you the most accurate results, especially for nitrites, because bacteria have had all night to convert nitrates. If you can't test first thing in the morning, try to hold your urine for at least 4 hours before testing.
To collect a midstream sample:
- Wash your hands
- Start urinating into the toilet
- After a second or two, hold the test strip (or collection cup) in the urine stream
- Finish urinating into the toilet
The "midstream" part is important because it flushes away bacteria and cells from the external area that could contaminate your sample and skew results.
Step 3: Dip the Strip
If you're using a collection cup, dip the test strip into the urine so that both test pads are fully submerged. Hold it there for 1 to 2 seconds — don't soak it. If you held the strip directly in your urine stream, that works too. Make sure both colored pads on the strip got wet.
Step 4: Remove and Wait
Pull the strip out and hold it horizontally (not at an angle) to prevent the chemicals from one pad running into the other. This is crucial — if the reagents mix, you'll get an inaccurate reading.
Now, start your timer. You'll typically need to wait:
- 60 to 120 seconds for the nitrite result
- 60 to 120 seconds for the leukocyte result
Check the specific timing instructions on your test strip package, as this can vary slightly between brands. Don't read the results too early (the reaction hasn't finished) or too late (the colors may continue to change and become unreliable after the reading window closes).
Step 5: Compare to the Color Chart
Hold the strip next to the color reference chart that came with your test strips. Match each test pad to the closest color on the chart. Good lighting matters here — read the strip under bright, natural or white light, not dim or yellow-toned lighting.
How to Read Your Results: What the Colors Mean
Here's where learning how to read UTI test strips really pays off. Each pad will change (or not change) color based on what's in your urine.
Leukocyte Results
- Negative (no color change): The pad stays its original color. No significant white blood cells detected — your body likely isn't fighting a urinary tract infection.
- Trace: A slight color shift, suggesting a small number of white blood cells. This could indicate a very early or mild infection, or it could be due to contamination of the sample.
- Positive (moderate to strong color change): The pad shifts noticeably toward purple or dark pink (depending on the brand). This indicates a significant presence of white blood cells, suggesting infection or inflammation.
Nitrite Results
- Negative (no color change): No nitrites detected. This means bacteria that convert nitrates weren't found — but remember, this doesn't completely rule out a UTI, since not all bacteria produce nitrites.
- Positive (any pink or red color change): Any color change on the nitrite pad, even faint, is considered a positive result. This strongly suggests bacterial presence in your urinary tract.
Interpreting Combined Results
Here's how to put both results together:
- Both Negative: A UTI is unlikely, though not completely ruled out. If you're having strong symptoms, retest in 24 hours with first morning urine or see your healthcare provider.
- Leukocytes Positive, Nitrites Negative: This could mean an early UTI, a UTI caused by bacteria that don't produce nitrites, or inflammation from another cause (like a kidney stone or vaginal infection). Worth monitoring closely and retesting, or seeing your provider if symptoms are significant.
- Leukocytes Negative, Nitrites Positive: This is uncommon but possible. It could indicate bacteria are present but your immune response hasn't ramped up yet. Treat this as a potential UTI and consult your healthcare provider.
- Both Positive: Strong indicator of a UTI. Contact your healthcare provider to discuss treatment, which will likely include a urine culture and antibiotics.
Understanding False Negatives (and Why They Happen)
A negative test strip result doesn't always mean you're in the clear. Here are the most common reasons for false negatives.
Dilute Urine
If you've been chugging water all day, your urine may be too diluted for the test to detect leukocytes or nitrites at accurate levels. This is why first morning urine or urine held for at least 4 hours is recommended.
Early-Stage Infection
If you test at the very first twinge of symptoms, the bacterial count and immune response might not yet be high enough to trigger a positive result. Retest in 12 to 24 hours if symptoms persist.
Non-Nitrite-Producing Bacteria
As mentioned, some UTI-causing bacteria don't produce nitrites. If your nitrite test is negative but you have classic UTI symptoms and positive leukocytes, the infection may be caused by a non-E. coli organism.
Medications and Supplements
High doses of vitamin C can interfere with the accuracy of both leukocyte and nitrite readings. Some antibiotics can also affect results. If you're taking these, mention it to your healthcare provider when discussing your results.
When to See a Doctor — Regardless of Your Test Strip Results
Test strips are a valuable screening tool, but they're not a complete diagnostic. See your healthcare provider if:
- You have severe symptoms — intense pain, fever, chills, nausea, or back pain (which could indicate a kidney infection)
- You see blood in your urine that doesn't resolve quickly
- Your symptoms persist for more than 48 hours despite home care
- You get recurrent UTIs (three or more per year) — you may need a urine culture to identify the specific bacteria and the best targeted treatment
- You're pregnant — UTIs during pregnancy require prompt medical treatment to prevent complications
- Your symptoms keep coming back after completing antibiotics — this could indicate antibiotic resistance or an underlying issue
A urine culture (which your doctor can order) is the definitive way to confirm a UTI, identify the specific bacteria, and determine which antibiotics will be effective.
Why Keeping Test Strips on Hand Is a Power Move
Here's the thing: UTI symptoms can overlap with other conditions — vaginal infections, interstitial cystitis, irritation from products, or even dehydration. Having UTI test strips at home means you don't have to guess. You can test at the first sign of discomfort and make informed decisions about whether you need to call your doctor or simply drink more water.
They're also incredibly useful for women who get recurrent UTIs. Tracking your results over time helps you and your healthcare provider see patterns and adjust your prevention strategy. Speaking of prevention, if you're dealing with frequent UTIs, consider adding Bye Bye UTI — a daily drink mix with D-Mannose and cranberry extract — to your routine. Prevention is always better than treatment.
Pro Tips for the Most Accurate Results
- Test with first morning urine whenever possible for the highest accuracy
- Don't let the strip sit in urine too long — a quick 1-2 second dip is all you need
- Hold the strip flat after dipping to avoid cross-contamination between pads
- Read results at the exact time specified — set a phone timer so you don't forget
- Use good lighting — color interpretation is everything with these tests
- Check the expiration date — expired strips can give unreliable results
- Store strips properly — keep the container sealed and away from moisture and direct sunlight
Frequently Asked Questions About UTI Test Strips
How accurate are at-home UTI test strips?
When used correctly, at-home UTI test strips have a sensitivity of approximately 75 to 90 percent for detecting UTIs. They're most accurate when both leukocyte and nitrite results are considered together. A positive result on both markers is highly reliable. However, a negative result doesn't definitively rule out a UTI, so always consider your symptoms alongside the test results.
Can I use UTI test strips during my period?
Menstrual blood can contaminate urine samples and cause false positive results, particularly on the leukocyte pad. If you need to test during your period, use a tampon or menstrual cup before collecting your sample to minimize contamination. If you get an unexpected positive result during your period, retest once your period ends or see your healthcare provider for a clean-catch sample.
How often can I use UTI test strips?
As often as you need to. There's no limit on how frequently you can test. If you're prone to UTIs, consider testing at the first sign of any urinary symptoms so you can catch infections early. Some women who get very frequent UTIs test periodically even without symptoms to catch asymptomatic bacteriuria.
What should I do if my test is positive?
Contact your healthcare provider. A positive at-home test warrants a follow-up with a medical professional who can confirm the diagnosis with a urine culture and prescribe appropriate treatment. In the meantime, stay well-hydrated and avoid holding your urine for long periods.
Can UTI test strips detect kidney infections?
Test strips can detect the markers associated with a UTI, and kidney infections are essentially UTIs that have traveled up to the kidneys. However, test strips can't distinguish between a bladder infection and a kidney infection. If you have UTI symptoms plus fever, back or flank pain, nausea, or vomiting, seek medical attention promptly — these could be signs of a kidney infection, which requires more aggressive treatment.
Do I still need to see a doctor if my test strip is negative but I have symptoms?
Yes. If you're experiencing burning, urgency, frequency, or pelvic pain and your test strip is negative, there could be several explanations: a false negative, a non-bacterial cause of your symptoms (like interstitial cystitis), or a vaginal infection causing similar symptoms. Your doctor can run additional tests to figure out what's going on.
