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Urinary Casts, Semiquantitative — Number per Low-Power Field

Published: August 9, 2026Updated: August 17, 2026

A urine microscopy test that estimates the number of casts in a urine sample, reported per low-power field. Casts can help assess kidney function and hydration.

Quick summary

["This test measures urinary casts, which may reflect hydration, kidney stress, or certain kidney conditions."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
9842-6
Short code
Casts #/area UrnS LPF
Synonyms
Casts #/area UrnS LPF
Category
liver
Sample
urine
Container
Sterile urine container
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
microscopy-light-lpf
CPT
84484
SNOMED
302774002
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What is this test?

This test looks for microscopic structures called casts in urine. Casts form when substances produced by the kidneys combine in the urine tubules, and the result is often reported as the number seen per low-power field.

Why might I need this test?

Urine cast testing may be included as part of a urinalysis or ordered when a clinician is evaluating dehydration, kidney injury, kidney disease, or symptoms such as swelling, nausea, or changes in urination.

How is the test performed?

A urine sample is examined with a microscope or a urine sediment analyzer. The laboratory estimates the number of casts and may also report the type of cast, which can provide additional information about the likely cause.

How do I prepare for the test?

Follow your clinician's or laboratory's collection instructions, which may include providing a clean-catch, midstream urine sample. Tell the laboratory if you recently exercised heavily, because strenuous exercise can temporarily increase urinary casts.

Reference range

Adult: 10-40 U/LN/A

Specimen: urine

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urine casts

Frequently asked questions

What are urinary casts?
Urinary casts are small structures made from proteins and other substances that form inside the kidney tubules. Their shape and composition can help clinicians interpret kidney-related findings.
Does a higher cast count always mean I have kidney disease?
No. Cast counts can rise temporarily with dehydration or strenuous exercise, and the type of cast matters. Your clinician will interpret the result alongside other urine tests, kidney tests, and your health history.
Is this the same as a routine urinalysis?
It is usually a component of urine microscopy, which is often performed as part of a routine urinalysis. Some laboratories also use automated equipment to estimate cast counts.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy