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Unit Code 83190:
Orthostatic Protein, Urine

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Useful For

Diagnosis of orthostatic proteinuria

 

As a second-order test for further characterization of proteinuria

<3 grams/24 hours, particularly in children or adolescents

Clinical Information

Orthostatic proteinuria refers to the development of increased

proteinuria that develops only when the person is upright and

resolves when recumbent or supine. This condition is usually

seen in children, adolescents, or young adults, and accounts for

the majority of cases of proteinuria in childhood.

 

Orthostatic proteinuria usually does not indicate significant underlying

renal pathology, and is usually not associated with other urine

abnormalities such as hypoalbuminemia, hematuria,

red blood cell casts, fatty casts, etc. Orthostatic proteinuria

typically resolves over time.

 

This test characterizes this condition by obtaining 2 urine

collections within a 24-hour time frame, 1 collection obtained

while the person is recumbent or supine, the other when upright.

Reference Values

Nighttime (supine) collection: <50 mg/spec

 

Daytime collection:

      Males: 0-150 mg/spec

      Females: 27-93 mg/spec

Interpretation

Supine urine protein excretion <50 mg/specimen with an elevated upright

or 24-hour urine collection (>150 mg for males, >93 mg for females) is

considered consistent with orthostatic proteinuria.

Cautions

It is not unusual for urine protein excretion derived from supine

collections to be somewhat lower than protein excretion derived from

upright collections. However, orthostatic or postural proteinuria is

characterized by a supine excretion rate of <50 mg/8 hrs.

Special Instructions and Forms

• Orthostatic Collection Instructions 

Clinical Reference

1.   Dodge WF, West EF, Smith EH, Harvey B:  Proteinuria and

      hematuria in school children:  Epidemiology and early natural

      history. J Pediatr 1976;88:327

 

2.   Hogg RJ, Portman RJ, Milliner D, et al:  Evaluation and

      management of proteinuria and nephritic syndrome in children.

      Pediatrics 2000;105:1242

 

3.   Addis T:  Prognosis in postural (orthostatic proteinuria). Forty

      to fifty-year follow-up of six patients after diagnosis. N Engl J Med

      1981;305:618

Key