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Chlorothiazide (Thiazide Diuretic) Urine Excretion Rate or Concentration

Published: August 9, 2026Updated: August 16, 2026

This test measures how your kidneys respond to a thiazide diuretic, a type of medication often used to manage high blood pressure or fluid retention. It helps assess kidney function and how well your body handles certain medications.

Quick summary

["This test helps doctors evaluate kidney function and drug metabolism in people taking thiazide medications."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
73450-9
Short code
Chlorthalidone ind plt IgM SerPl Ql FC
Synonyms
Chlorthalidone ind plt IgM SerPl Ql FC
Category
hematology
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
CPT
82784
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your doctor may order this test if you’re taking a thiazide diuretic (like chlorothiazide) and want to check how your kidneys are processing it. It can also help diagnose conditions like kidney disease or determine if your medication is working as intended.

What to Expect Before the Test

You’ll likely drink plenty of water before the test to ensure your urine is diluted. You may also be given a specific dose of chlorothiazide to take. Bring any medications you’re currently taking to your appointment.

During the Test

You’ll provide a urine sample, possibly over a short period (like 24 hours) or at specific intervals. The sample is tested for the presence of chlorothiazide or its metabolites to measure excretion or concentration.

What the Results Mean

Results help your doctor see if your kidneys are effectively removing the medication from your body. Abnormal results might indicate kidney issues or how well your body handles the drug.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: This test is critical for patients on thiazide diuretics to monitor kidney function, drug clearance, and potential side effects. It helps prevent complications like electrolyte imbalances or kidney damage.

Short name

Urine Thiazide Response Test

Frequently asked questions

Will I need to change my diet before the test?
You may need to avoid certain foods or fluids (like salt) for a short time, depending on your doctor’s instructions. Always follow their specific guidance to get accurate results.
How long will it take to get my results?
Results are typically available within a few days to a week, depending on your lab. Your doctor will discuss them with you during your follow-up visit.
Can I take my usual medications on the day of the test?
Yes, but inform your doctor about all medications, including over-the-counter drugs or supplements, to avoid interfering with the test results.
  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 16, 2026. · Read our editorial policy