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Phosphate Substance Concentration in Dialysate

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

This test measures the amount of phosphate in dialysate, the fluid used during dialysis. It may help assess how well phosphate is being removed during treatment.

Quick summary

["The result reflects phosphate removal during dialysis and should be interpreted along with blood phosphate results and the overall treatment plan."]

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

Key facts at a glance

LOINC
34938-1
Short code
Phosphate Dial fld-sCnc
Synonyms
Phosphate Dial fld-sCnc
Category
electrolyte
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
2.5
Ref high
4.5
Critical range
1 N/A – —
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
84100
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

What Is Dialysate?

Dialysate is a sterile solution used to clean the blood during hemodialysis. It contains substances that help remove waste, excess electrolytes, and fluid from the body.

What Does This Test Measure?

The test measures phosphate concentration in the dialysate. Phosphate is an essential mineral that supports bones, nerves, muscles, and many cellular functions.

Why Is Dialysate Phosphate Measured?

Measuring phosphate in dialysate can help evaluate the effectiveness of phosphate clearance during dialysis. It is generally considered together with pre- and post-dialysis blood phosphate measurements.

How Is the Result Used?

Results may help guide dialysis prescription changes or additional phosphate-removal strategies. Your dialysis team will interpret the value based on the laboratory method, treatment details, and your blood phosphate level.

Reference range

Adult: 2.5-4.5 mg/dLN/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.

◆Associated findings1

Short name

Dialysate Phosphate

Frequently asked questions

Is this the same as a blood phosphate test?
No. This test measures phosphate in dialysate, whereas a standard blood phosphate test measures phosphate in blood. The results provide different but complementary information.
Does a low dialysate phosphate result mean phosphate removal is inadequate?
Not necessarily. Interpretation depends on the prescribed dialysate composition, the amount of phosphate transferred from the blood, and other dialysis and blood phosphate measurements. A nephrologist should interpret the result.
Can I change my dialysis treatment based on this result?
No. Dialysate phosphate is one part of a broader assessment. Changes to phosphate levels or dialysis treatment should be made only by your dialysis or medical team.
  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