Creatinine 24 Hour Urine Test (24-hour urine creatinine) Biomarker Testing
It measures how much creatinine you excrete in a full day to check collection quality and kidney function context, with easy ordering through Vitals Vault/Quest.
With Vitals Vault, you have access to a comprehensive range of biomarker tests.
A creatinine 24 hour urine test measures the total amount of creatinine your kidneys excrete over a full day. Because creatinine is produced at a fairly steady rate from muscle, the “per day” number can help confirm whether a 24-hour urine collection was complete and can add context to other urine findings.
This test is often ordered alongside a 24-hour urine protein or albumin measurement, or as part of a creatinine clearance calculation that also uses a blood creatinine level. The value is not just the number itself, but what it tells you about kidney filtration, hydration, and whether the sample you collected reflects a true 24-hour period.
If you are comparing testing options, the biggest practical difference is the collection method: you collect all urine for 24 hours at home, then return the container to the lab. Getting the collection right matters as much as the lab measurement.
Do I need a Creatinine 24 Hour Urine test?
You may benefit from a creatinine 24 hour urine test if your clinician wants a more complete picture of kidney function than a single urine sample can provide. It is commonly used when you are evaluating protein in the urine, monitoring known kidney disease, or trying to confirm that a 24-hour urine collection was done correctly.
This test is also useful when your blood creatinine or estimated GFR (eGFR) does not seem to match your body size, muscle mass, or clinical picture. In those situations, a timed urine collection can help your clinician interpret results more accurately, especially when paired with a blood creatinine drawn during the collection window.
You might be asked to do this test if you have swelling in your legs, foamy urine, high blood pressure, diabetes, autoimmune disease, recurrent kidney stones, or medication use that can affect the kidneys. Pregnancy-related evaluation is another scenario where 24-hour urine testing may be used, depending on your care plan.
This test supports clinician-directed care, but it cannot diagnose a condition by itself. Your result is most meaningful when it is interpreted alongside your symptoms, medications, and related blood and urine markers.
This is a laboratory measurement performed in a CLIA-certified lab; results should be interpreted in clinical context and are not a standalone diagnosis.
Lab testing
Ready to order a Creatinine 24 Hour Urine test through Vitals Vault?
Schedule online, results typically within about a week
Clear reporting and optional clinician context
HSA/FSA eligible where applicable
Get this test with Vitals Vault
If you want to check 24-hour urine creatinine, Vitals Vault lets you order the lab test and complete the collection using a lab-provided container and instructions. You then drop off the specimen at a participating lab location for processing.
Because collection quality is a major source of confusion, PocketMD can help you review how to collect a true 24-hour sample, what to do if you miss a void, and how to think about your result in relation to kidney function labs like serum creatinine, eGFR, and urine protein.
After your results post, you can use PocketMD to generate questions for your next appointment and decide whether a repeat collection or companion testing would make your next step clearer. If you are tracking a known issue, reordering through Vitals Vault makes it easier to compare trends over time using the same testing pathway.
- Order online and complete the 24-hour collection at home
- Results delivered in a clear, shareable format for your clinician
- PocketMD helps you interpret results and plan sensible follow-up
Key benefits of Creatinine 24 Hour Urine testing
- Helps confirm whether your 24-hour urine collection was complete and usable.
- Adds context to 24-hour urine protein or albumin results by anchoring them to creatinine excretion.
- Supports creatinine clearance calculations when paired with a timed blood creatinine.
- Can clarify kidney function assessment when eGFR may be less reliable (for example, unusual muscle mass).
- Helps your clinician interpret kidney-related symptoms such as swelling, foamy urine, or unexplained hypertension.
- Useful for monitoring kidney disease or treatment effects over time with consistent collection methods.
- Gives you a concrete data point to discuss next steps with PocketMD and your clinician.
What is Creatinine 24 Hour Urine?
Creatinine is a waste product made when your muscles use energy (from creatine phosphate). Your kidneys normally filter creatinine from the blood and excrete it into urine. A creatinine 24 hour urine test measures the total amount of creatinine in all urine you produce over a full 24-hour period.
Unlike a random urine creatinine (a single sample), the 24-hour measurement reflects daily excretion. That makes it helpful for two main reasons: it can be used to estimate how well your kidneys are clearing creatinine (creatinine clearance), and it can be used as a “reality check” on whether a 24-hour urine collection was complete.
Because creatinine production is influenced by muscle mass, age, sex, diet (especially recent meat intake), and activity, there is no single “perfect” number for everyone. Your lab report may include a reference interval, but interpretation is most accurate when your clinician considers your body size, collection volume, and related kidney markers.
How it relates to creatinine clearance
Creatinine clearance is an estimate of kidney filtration calculated from urine creatinine concentration, total urine volume over time, and a blood creatinine level. A 24-hour urine creatinine result is often part of that calculation, but the clearance value is only as accurate as the collection.
Why collection quality matters
If you miss urine during the 24-hour window, the total creatinine excretion can look falsely low. If you collect longer than 24 hours, or include urine outside the window, the total can look falsely high. That is why instructions (start time, end time, and discarding the first void) are not just paperwork—they directly affect your result.
What do my Creatinine 24 Hour Urine results mean?
Low 24-hour urine creatinine
A low total creatinine excretion over 24 hours often points to an incomplete collection, especially if the urine volume seems unusually low for you or if you know you missed a void. It can also be lower in people with lower muscle mass, older age, or reduced dietary protein intake. In some cases, it may reflect reduced kidney excretion in advanced kidney dysfunction, but this is usually interpreted alongside blood creatinine, eGFR, and other urine findings.
In-range (expected) 24-hour urine creatinine
An in-range result suggests your collection likely captured a true 24-hour period and that daily creatinine excretion is consistent with your body size and muscle mass. When this number looks reasonable, it increases confidence in other 24-hour urine results collected at the same time, such as total protein or albumin. Your clinician may still focus more on the companion markers (protein, albumin, sodium, calcium, or stone-risk analytes) depending on why the test was ordered.
High 24-hour urine creatinine
A high total creatinine excretion can happen if you have higher muscle mass, did intense exercise, or had a high meat intake around the collection. It can also occur if the collection ran longer than 24 hours or included urine outside the intended window. A high number is not automatically “bad,” but it can change how other 24-hour urine results are interpreted, so it is worth reviewing collection timing and recent activity.
Factors that influence 24-hour urine creatinine
Muscle mass is one of the biggest drivers of creatinine production, so two people with the same kidney function can have different 24-hour excretion. Hydration changes urine volume but usually does not change the total daily creatinine as much as collection errors do. Recent heavy exercise, high meat intake, and some supplements (for example, creatine) can shift results. Medications and kidney conditions that affect filtration or tubular handling can also influence interpretation, which is why pairing this test with serum creatinine and urine protein/albumin is common.
What’s included
- Creatinine, 24 Hour Urine
Frequently Asked Questions
How do I do a 24-hour urine collection correctly?
You typically start in the morning by urinating and discarding that first void, then collect all urine for the next 24 hours into the provided container. At the same time the next morning, you collect your final urine and include it. Keep the container stored as instructed (often refrigerated). If you miss a collection, tell the lab or your clinician because it can make the total result unreliable.
Do I need to fast for a creatinine 24-hour urine test?
Fasting is usually not required for the urine collection itself. However, your clinician may pair the collection with a blood draw (serum creatinine or other labs) that may have separate preparation instructions. If you want the cleanest comparison, avoid unusually heavy exercise and large changes in meat intake during the collection unless your clinician advises otherwise.
What is a normal 24-hour urine creatinine range?
Reference ranges vary by lab and are influenced by muscle mass, age, and sex, so the “normal” interval on your report is the best starting point. The more practical question is whether your value looks plausible for you and whether it supports that the collection was complete. Your clinician may interpret your result alongside urine volume and any companion 24-hour tests.
What does low 24-hour urine creatinine mean?
Most commonly, it means the collection was incomplete (missed urine during the 24-hour window) or the timing was off. It can also be seen with lower muscle mass or low protein intake. If kidney disease is a concern, your clinician will look at blood creatinine, eGFR, urine protein/albumin, and sometimes imaging to understand the full picture.
What does high 24-hour urine creatinine mean?
It can reflect higher muscle mass, recent intense exercise, or higher meat intake. It can also happen if the collection went longer than 24 hours or included urine outside the window. A high value is not automatically dangerous, but it should prompt a quick review of collection timing and recent activity so other 24-hour results are interpreted correctly.
Is this the same as a urine creatinine (random) test?
No. A random urine creatinine is measured in a single urine sample and is often used to normalize other spot urine tests (like albumin-to-creatinine ratio). The 24-hour urine creatinine test measures total daily excretion and is more sensitive to collection completeness and daily variability.
When should I repeat a 24-hour urine creatinine test?
You might repeat it if the collection was likely incomplete, if your clinician needs to confirm a borderline finding, or if you are monitoring a condition over time. The timing depends on the reason for testing—sometimes a repeat is done soon for collection quality, while monitoring may be spaced weeks to months apart. PocketMD can help you plan questions to ask so your retest answers a specific clinical question.