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Bicarbonate (HCO₃⁻) in Dialysate Fluid

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

This test measures the amount of bicarbonate, a key buffer in your body’s blood, found in the dialysate fluid used during hemodialysis. It helps assess how well your dialysis is maintaining your blood chemistry.

Quick summary

["This test helps monitor your dialysis treatment’s effectiveness in balancing acid-base balance during kidney dialysis."]

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

Key facts at a glance

LOINC
48631-6
Short code
HCO3 p dialysis Ser-sCnc
Synonyms
HCO3 p dialysis Ser-sCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
22
Ref high
28
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Is This Test Done?

Your healthcare provider may order this test if you’re undergoing hemodialysis to check if your dialysate solution is properly balancing your blood’s acidity (pH) and removing waste products like acid. It’s particularly important if you have metabolic acidosis or if your dialysis setup requires precise adjustments to bicarbonate levels.

What Does the Result Mean?

Bicarbonate levels in dialysate are typically adjusted based on your blood’s current acidity. Low bicarbonate in dialysate may lead to too much acid buildup in your blood, while high levels could dilute your blood unnecessarily. Your provider will compare this result with your blood bicarbonate levels to fine-tune your treatment.

How Is This Test Performed?

During hemodialysis, a dialysate solution containing bicarbonate is pumped through your bloodstream. A small sample of this dialysate fluid is collected and tested for bicarbonate concentration using a specialized method, often automated in dialysis machines.

What Can Affect This Test?

Several factors can influence bicarbonate levels in dialysate, including the type of dialysis machine used, the concentration of bicarbonate in the dialysate solution itself, and how well your blood is being filtered. Your provider may also consider your overall health, medications, and other lab results when interpreting this test.

Reference range

NCBI: HCO3- 22-28 mmol/LN/A

Specimen: serum

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Abnormal bicarbonate levels in dialysate can indicate issues with your dialysis process. For example, if bicarbonate is too low, your blood may become too acidic (metabolic acidosis), which can cause fatigue, confusion, or muscle cramps. If bicarbonate is too high, it may lead to over-dilution of your blood, potentially causing weakness or fluid imbalances. Regular monitoring helps prevent these complications and ensures your treatment is tailored to your needs.

Short name

Dialysate Bicarbonate

Frequently asked questions

Why is my dialysate bicarbonate level checked regularly?
Regular checks help ensure your dialysis is effectively balancing your blood’s acidity. If your levels are consistently off, your provider may adjust your dialysate settings to better match your body’s needs, improving your overall comfort and health.
What happens if my dialysate bicarbonate level is too low?
If your dialysate bicarbonate is too low, your blood may retain too much acid, leading to symptoms like fatigue, shortness of breath, or confusion. Your provider will likely increase the bicarbonate concentration in your dialysate or monitor your blood chemistry more closely to prevent this.
Can diet affect my dialysate bicarbonate test results?
Dietary factors like high-protein or high-acid foods can indirectly influence your blood chemistry, which may affect how your dialysis machine adjusts bicarbonate levels. However, the dialysate bicarbonate test itself measures the fluid used in dialysis, not your diet directly. Your provider will consider your overall health and lab results when interpreting this test.
  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