Protein Electrophoresis, 24-Hour Urine

CPT: 84156; 84166
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Synonyms

  • Electrophoresis, Protein, 24-Hour Urine
  • Globulins, 24-Hour Urine

Test Includes

Graph with quantitation of total urine protein; urine albumin; urine α1; urine α2; urine β; urine γ-globulin fractions if present; quantitation of M-spike if present


Special Instructions

Record total 24-hour urine volume on the test request form.


Expected Turnaround Time

3 - 5 days



Related Documents


Specimen Requirements


Specimen

Urine (24-hour)


Volume

20-mL aliquot


Minimum Volume

6-mL aliquot (Note: This volume does not allow for repeat testing.)


Container

12-mL plastic transport tube (Labcorp No. 23597) without preservative


Collection

Instruct patient to void at 8 a.m. and discard the specimen. Then collect all urine for the next 24 hours, including the 8 a.m. void the next morning. Label container with the patient's name, date and time the collection started and ended. Measure total volume. Mix well.


Storage Instructions

Refrigerated (preferred) or room temperature


Stability Requirements

Temperature

Period

Room temperature

14 days

Refrigerated

14 days

Frozen

14 days

Freeze/thaw cycles

Stable x1


Causes for Rejection

Preservative added


Test Details


Use

Evaluate myeloma, macroglobulinemia of Waldenström, lymphoma, amyloidosis; differentiate between normal renal function, glomerular proteinuria, and tubular proteinuria. Increased glomerular permeability leads to higher concentrations of large proteins in the glomerular filtrate. Diminished tubular reabsorptive capacity results in a marked increase in urinary excretion of low molecular weight problems.


Limitations

May not detect pathologic light chains due to insufficient sensitivity. Should be followed with immunoelectrophoretic or immunofixation study performed on concentrated urine. Optimal specimen when looking for a free monoclonal light chain (Bence Jones protein) is a 24-hour collection.


Methodology

Electrophoresis on agarose media


Reference Interval

Normal pattern. See table.

24-Hour Urine Protein Electrophoresis Interpretation

Pattern Description

Electrophoretic Zones

Total Protein

(mg/d)

Albumin

α1

α2

β

γ

*Looks like serum protein electrophoretogram.

+ = mildly elevated.

++ = moderately elevated.

+++ = markedly elevated.

+/– = may or may not be present.

Normal

<150

+/–

+/–

+/–

Selective glomerular proteinuria

mild

<1500

++

+

+

severe

>1500

+++

++

++

Nonselective glomerular proteinuria*

>3000

+++

++

++

++

++

Tubular proteinuria

<1500

Trace to +

Trace

++

++

Trace of light chain

Mixed glomerular and tubular proteinuria

+++

+

++

+

+

Albuminuria

>150

++

Overflow proteinuria from acute phase response

Trace or present

++

++

Trace

Trace

Overflow proteinuria with monoclonal spike

(spike) or ++

(spike) or ++


Additional Information

A serum protein electrophoresis should be reviewed concurrently if one has not been recently studied. In nonselective glomerular proteinuria, the urine electrophoretic pattern is often a nonspecific one which may be called “mirror image” to that of the serum. Contamination of the urine with blood can give a similar pattern. With selective glomerular permeability, albumin, α1 proteins, and transferrin are the predominant proteins identified on the urine protein electrophoresis, with a relative absence of heavier molecular weight proteins (ie, α2-macroglobulin and immunoglobulins). With tubular proteinuria, low molecular weight proteins (α2- and β2-microglobulins) are predominant, with trace amounts of albumin. So called “overflow proteinuria” occurs when low molecular weight proteins are filtered through the glomerulus in increased amounts.


LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
003368 Protein Electro, 24-Hour Urine 81231-3 013664 Protein,Total,Urine mg/dL 2888-6
003368 Protein Electro, 24-Hour Urine 81231-3 013219 Prot,24hr calculated mg/24 hr 2889-4
003368 Protein Electro, 24-Hour Urine 81231-3 133686 Albumin, U % 13986-5
003368 Protein Electro, 24-Hour Urine 81231-3 133694 Alpha-1-Globulin, U % 13984-0
003368 Protein Electro, 24-Hour Urine 81231-3 133702 Alpha-2-Globulin, U % 13987-3
003368 Protein Electro, 24-Hour Urine 81231-3 133710 Beta Globulin, U % 13988-1
003368 Protein Electro, 24-Hour Urine 81231-3 133728 Gamma Globulin, U % 13989-9
003368 Protein Electro, 24-Hour Urine 81231-3 133729 M-Spike, % % 42484-6
003368 Protein Electro, 24-Hour Urine 81231-3 133734 M-Spike, mg/24 hr mg/24 hr 42482-0
003368 Protein Electro, 24-Hour Urine 81231-3 133800 Please note: 77202-0
003368 Protein Electro, 24-Hour Urine 81231-3 003724 PDF 11502-2

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