Urinalysis (Urine Dipstick): Every Marker Explained — Blood, Protein, Glucose, Ketones and More
A urine dipstick can flag kidney disease, infection, diabetes, and dehydration in under a minute. Learn what every colour square means, what to trust, and what to repeat.
A standard urine dipstick reports 8–10 markers: protein, blood, leukocyte esterase, nitrites, glucose, ketones, bilirubin, urobilinogen, specific gravity and pH. Nitrites + leukocytes together strongly suggest a urinary tract infection; protein above trace on repeat testing is investigated for kidney disease; glucose on the dipstick usually reflects blood sugar above 180 mg/dL.
The urine dipstick is a rapid, low-cost screening tool. Protein detection is most sensitive to albumin — for accurate quantification use a spot albumin-to-creatinine ratio (ACR). Blood on the dipstick can reflect red cells, free haemoglobin (haemolysis), or myoglobin (rhabdomyolysis); microscopy differentiates them. Leukocyte esterase + nitrites together carry the highest positive predictive value for UTI (~85%). Glucose spills into urine when plasma glucose exceeds ~180 mg/dL. Ketones appear in DKA, prolonged fasting, ketogenic diet, and severe vomiting. Specific gravity 1.010–1.020 is normal hydration; below 1.005 suggests diabetes insipidus in the right clinical context.
- Normal dipstick
- All markers negative or trace
- Best UTI signal
- Nitrites POSITIVE + leukocytes POSITIVE
- Protein trace on one sample
- Repeat + urine ACR before workup
- Glucose positive means
- Blood glucose usually > 180 mg/dL
- Specific gravity 1.010
- Well-hydrated
The ten markers, one by one
Protein (or albumin): dipstick detects mostly albumin. Trace or 1+ on a single sample is often incidental (post-exercise, dehydration, fever). Persistent ≥ 1+ warrants a spot albumin-to-creatinine ratio (ACR). ACR ≥ 30 mg/g is significant albuminuria and is a stage marker in chronic kidney disease.
Blood: detects red cell peroxidase, so it also reads positive for free haemoglobin (haemolysis) and myoglobin (rhabdomyolysis). Microscopy shows red cells if bleeding, or a clear urine with strong-positive dipstick if pigment. Persistent haematuria over age 40 needs urology workup — bladder or upper tract cancer risk.
Leukocyte esterase and nitrites: leukocyte esterase indicates pus cells; nitrites indicate that Enterobacteriaceae (E. coli, Klebsiella, Proteus) have converted urinary nitrates to nitrites — a strong bacteria-specific signal. The two together are the most reliable dipstick pattern for UTI. A negative nitrite does NOT rule out UTI because staphylococci, enterococci, and some Pseudomonas do not produce nitrites.
Glucose: renal threshold is around 180 mg/dL; below that, no glucose spills. Positive dipstick usually means diabetes with poor control OR the rare renal glycosuria (SGLT2 inhibitor use or a familial low renal threshold).
Ketones: appear in fasting, ketogenic diet, alcohol excess, prolonged vomiting, and diabetic ketoacidosis. A diabetic with ketones + high glucose is a medical emergency.
Bilirubin and urobilinogen: bilirubin appears in cholestatic liver disease; urobilinogen rises in haemolysis and falls in complete biliary obstruction. Neither is routinely useful in isolation.
Specific gravity: 1.010–1.020 reflects normal hydration; > 1.030 dehydration; < 1.005 diabetes insipidus, water loading, or lithium effect.
pH: usually 5.0–7.5. Persistently high pH (> 7) with UTI suggests Proteus or Klebsiella (they produce urease and alkalinise urine).
Common dipstick patterns
| Pattern | Suggestive of | Next step |
|---|---|---|
| Nitrites + leukocytes positive | Urinary tract infection | Send urine culture; treat empirically if symptomatic |
| Blood positive, no red cells on microscopy | Myoglobin or haemoglobin | CK for rhabdomyolysis, haemolysis screen |
| Protein 2+, no other abnormalities | Kidney disease vs orthostatic proteinuria | Spot ACR + eGFR + repeat on early-morning sample |
| Glucose positive, ketones positive | Diabetes with ketosis | Immediate glucose check; ketoacidosis workup if unwell |
| Bilirubin positive, urobilinogen absent | Complete biliary obstruction | Liver enzymes, ultrasound |
| Specific gravity < 1.005 fixed | Diabetes insipidus | Water deprivation test, sodium |
Why dipstick results can mislead
Concentrated urine (specific gravity > 1.020) exaggerates protein and blood positives. Dilute urine can hide real disease. Vitamin C at high dose interferes with several strip readings (false-negative blood, glucose, nitrites). Contamination with menstrual blood, vaginal discharge, or povidone-iodine skin cleanser can produce false positives. A first-morning midstream sample is the most reliable for kidney and protein assessment.
- Ketones POSITIVE with glucose POSITIVE — assess for diabetic ketoacidosis.
- Nitrites POSITIVE with fever, back pain, or vomiting — suspect pyelonephritis.
- Blood on dipstick over age 40 with clots or weight loss — urgent urology referral.
- Protein 3+ with new peripheral oedema — nephrotic syndrome.
- Persistent high pH + UTI symptoms — urease-producing infection (Proteus), stone risk.
Dipstick follow-up
- 1Nitrites + leukocytes positive with UTI symptoms?Send culture; treat empirically per local resistance patterns. Adjust after culture sensitivity.
- 2Isolated haematuria (blood only) confirmed on microscopy?Under 40 with UTI cleared → repeat in 6 weeks. Over 40 or persistent → urology referral for cystoscopy and upper tract imaging.
- 3Protein positive on one sample?Repeat on early-morning sample. If persistent → spot albumin-to-creatinine ratio + eGFR. ACR ≥ 30 = significant albuminuria.
- 4Glucose positive without diabetes?Check plasma glucose and HbA1c. If both normal → consider SGLT2 inhibitor use or familial renal glycosuria.
- 5Specific gravity persistently low?Screen for diabetes insipidus (sodium, water deprivation test), lithium exposure, hypercalcaemia.
Related questions people ask
- What does trace protein in urine mean?
- Is blood in urine always serious?
- Can I have a UTI with a negative dipstick?
- What is albumin-to-creatinine ratio?
- What causes ketones in urine?
- Does dehydration change urine test results?
- Why is my urine specific gravity high?
Frequently asked questions
- Dipstick is fast and cheap — combine with clinical picture, do not read in isolation.
- Nitrites + leukocytes together strongly suggest UTI.
- Persistent protein needs ACR quantification.
- Blood positive without red cells suggests myoglobin or haemoglobin.
- Glucose + ketones together in a diabetic is an emergency.
- Vitamin C, menstrual contamination, and hydration status all affect readings.
References
3 sources- AAFPUrinalysis: A Comprehensive Review
US primary-care review of dipstick interpretation.
aafp.org
- NICE CG54Urinary tract infection in adults
UK UTI diagnostic and management guideline.
nice.org.uk
- EAUGuidelines on Urological Infections
European urology society UTI pathway.
uroweb.org
Evidence Snapshot
This snapshot shows verified evidence records matched to this article. It is not a diagnosis or personal medical advice.
A routine urinalysis typically combines physical inspection, chemical dipstick testing and, when indicated, microscopic examination of the urine to screen for a range of urinary and systemic conditions.
Limitation. Findings on a single urinalysis are commonly non-specific and often require repeat testing or further evaluation.
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