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UW Health SMPH
American Family Children's Hospital

UW Hospital and Clinics Lab Test Directory

Test Name: Immunofixation with Reflex to Quantitation, Urine, 24 Hours


CPT Code(s): 86335, 84156; if reflexed to Quantitation add 84166

Test Description: Test Component:

Urine immunofixation and quantitative urine protein.  Reflex to urine protein electrophoresis if applicable.

Methodology: Gel Electrophoresis

Clinical Significance: Immunofixation is used to test for and classify light chains (Bence Jones protein) in urine. Diseases associated with light chains in urine include gammopathy, amyloidosis, multiple myeloma and other plasma cell dyscrasias. When a measurable light chain band of restricted heterogeneity is detected, the sample is reflexed to urine electrophoresis for semi-quantitation of  the band.

Days Performed: Mon-Fri, dayshift - day varies.

Turnaround Time: Stat: Not available stat.
Routine: 3 working days.

Specimen Requirements

Specimen: 24 hour timed urine

Collection Instructions: No preservative

Collection Container: Preferred: 24 hour urine container
Also Acceptable: 24 hour urine container

Collection Volume: Preferred: Entire collection
Pediatrics: Entire collection

Sample Analyzed: Urine aliquot

Volume Required: Preferred: 10 mL
Pediatrics: 10 mL

Specimen Processing: Refrigerate specimen.

Specimen Transport: Transport entire collection to UWHC Core Laboratory (B4/220) at close of collection.  

Outreach Specimen Transport: Send aliquot from a well-mixed 24 hour collection in a sterile container with a coolant pack.

Unacceptable Criteria: Random urine collections.
Urines with bloody supernatants are acceptable but not desireable.
Urines with preservatives are not acceptable.

Stability: Ambient: Not acceptable
Refrigerated: 1 week
Frozen: 3 months for concentrated sample at -20C. Note: Avoid repeat freeze and thaw.


Reference Interval:


A written interpretive report with the scan is issued as a separate report. 


Test Limitations:

For reflex urine protein electrophoresis, the total urine protein method may underestimate the tubular and light chain protein fractions causing an underestimate in the semi-quantitative protein values reported by electrophoresis. The percent relationship of light chain proteins to tubular proteins and the ability to detect light chains is not affected.

Additional Information:

A professional fee is associated with this test.

urine immunofixation with reflex, reflex urine immunofixation electrophoresis, reflex UIFIX

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