II. Pathophysiology

  1. Glomerulus is permeable
    1. Molecular Weight under 60,000 Daltons may be filtered
    2. Albumin (MW 65,000) should not be filtered
  2. Normal Urinary Protein Excretion <150 mg/day
    1. Immunoglobulin (20,000 Daltons) 20%
    2. Albumin (65,000 Daltons) 40%
    3. Tamm-Horsfall Mucoprotein (distal tubule secrete) 40%

III. Causes

IV. Labs: Step 1

  1. Qualitative Protein: Random dipstick Urinalysis
    1. Obtain first morning void
    2. See Urine Protein
    3. Confirm Proteinuria with Sulfosalicylic Acid Test or quantitative Protein in step 2
  2. Microscopic Urinalysis findings of renal disease
    1. Urine fats (Nephrotic Syndrome)
    2. Urine WBCs without bacteruria (Renal Interstitial)
    3. Dysmorphic erythrocytes (Glomerular disease)
    4. Cellular or Granular Casts (chronic renal disease)
    5. Urine Eosinophils
      1. Drug-induced Acute Interstitial Nephritis
  3. Criteria for Step 2 evaluation below
    1. Nephrology consult for positive microscopic findings
    2. Urinalysis with 3+ to 4+ Urine Protein
    3. Urine Protein trace to 2+ on 2-3 Urinalysis in 1 month
      1. Repeat if related to transient cause (e.g. UTI, Exercise, Fever, CHF, Dehydration)

V. Labs: Step 2

  1. Quantitative Protein (2 samples within 3-6 months) severe cutoffs
    1. Urine Albumin to Creatinine Ratio (random urine) 500-1000 mg/g or
    2. Urine Protein to Creatinine Ratio (random urine) 300 mg/g or
    3. Urine Protein 24 Hour collection 2 grams/day
  2. Interpretation of 24 Hour Urine Protein Excretion or Albumin to Creatinine Ratio
    1. Severe Proteinuria, Macroalbuminuria criteria met
      1. Nephrology Consultation
      2. Determine Creatinine Clearance
      3. Monthly monitoring (see below)
    2. Proteinuria level below cutoffs listed above
      1. Determine Creatinine Clearance
      2. Creatinine Clearance normal
        1. Orthostatic Proteinuria
          1. Consider in age under 30 years
          2. Collect Split 24 Hour Urine Protein
        2. Isolated poteinuria
        3. Recheck every 6 months
      3. Creatine Clearance decreased
        1. Consider nephrology Consultation
        2. Monthly monitoring (see below)

VI. Monitoring

  1. Frequency (see lab protocol above)
    1. Orthostatic Proteinuria: every 1-2 years
    2. Isolated Proteinuria (<2 grams/day): every 6 months
    3. Large Proteinuria (>2 grams/day): every month
  2. Testing
    1. Blood Pressure
    2. Urinalysis
    3. Renal Function test
  3. Nephrology Consultation criteria (see lab protocol)
    1. Large Proteinuria (>2 grams/day)
    2. Urine microscopy positive for signs of renal disease
    3. Renal Insufficiency (decreased Creatinine Clearance)

VIII. References

  1. Carroll (2000) Am Fam Physician 62:1333-40 [PubMed]
  2. Molitch (2004) Diabetes Care 27(suppl 1): S79-S83 [PubMed]
  3. Dornbrand (1992) Adult Ambulatory Care, p. 270-4
  4. Friedman (1991) Problem Oriented Diagnosis, p. 261-3

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Related Studies

Ontology: Proteinuria (C0033687)

Definition (CHV) abnormal presence of protein in urine
Definition (CHV) abnormal presence of protein in urine
Definition (NCI_CTCAE) A disorder characterized by laboratory test results that indicate the presence of excessive protein in the urine. It is predominantly albumin, but also globulin.
Definition (NCI) The presence of excessive protein, chiefly albumin but also globulin, in the urine.
Definition (MSH) The presence of proteins in the urine, an indicator of KIDNEY DISEASES.
Definition (CSP) presence of excess protein in the urine.
Concepts Finding (T033)
MSH D011507
ICD9 791.0
ICD10 R80 , R80.9
SnomedCT 207310001, 207315006, 158568007, 167279003, 144515004, 158565005, 236719005, 232691000, 29738008
LNC LA18970-6
English Proteinurias, PROTEINURIA, Proteinuria NOS, [D]Proteinuria, [D]Proteinuria NOS, [D]Proteinuria (context-dependent category), [D]Proteinuria NOS (context-dependent category), proteinuria, proteinuria (diagnosis), Urinary protein positive, Protein urine positive, Proteinuria present, Proteinuria [Disease/Finding], proteinurias, Proteinuria, unspecified, [D]Proteinuria NOS (situation), [D]Proteinuria (situation), Proteinuria (disorder), Abnormal presence of protein in urine, Proteinuria (finding), Proteinuria, NOS, Proteinuria [Ambiguous], Proteinuria
French PROTEINURIE, Protéine dans l'urine positive, Protéine urinaire positive, Protéinurie
Portuguese PROTEINURIA, Proteína na urina positiva, Proteinúria presente, Proteinúria
Spanish PROTEINURIA, Proteínas positivas en orina, Presencia de proteinuria, [D]proteinuria (categoría dependiente del contexto), [D]proteinuria, SAI (categoría dependiente del contexto), albuminuria, [D]proteinuria, SAI (situación), [D]proteinuria, SAI, [D]proteinuria (situación), [D]proteinuria, presencia anormal de proteínas en orina, proteinuria (hallazgo), proteinuria, Proteinuria
German PROTEINURIE, Proteinurie nachweisbar, Urinprotein positiv, Protein im Urin positiv, Proteinurie
Dutch urinair eiwit positief, eiwit urine positief, aanwezige proteïnurie, proteïnurie, Proteïnurie
Italian Presenza di proteine nelle urine, Proteine urinarie positive, Proteinuria
Japanese 蛋白尿陽性, 蛋白尿, 尿蛋白陽性, タンパクニョウ, ニョウタンパクヨウセイ, タンパクニョウヨウセイ
Swedish Äggvita i urin
Czech proteinurie, Proteinurie, Přítomnost proteinurie, Bílkovina v moči pozitivní
Finnish Proteinuria
Polish Białkomocz
Hungarian Fehérje vizeletben pozitív, proteinuria kimutatható, proteinuria, Vizelet fehérje pozitív
Norwegian Proteinuri, Eggehvite i urinen