Proteinuria provides diagnostic and prognostic information about renal disease. It is associated with hypertension, obesity, and vascular disease, and can predict risks of chronic kidney disease progression, cardiovascular disease, and mortality. Monitoring proteinuria is important for assessing treatment response, as protein-lowering therapies may be renoprotective. A thorough history, physical exam, urinalysis, and further tests are needed to determine the type and cause of proteinuria and rule out underlying conditions in order to begin appropriate treatment.

1. PROTEINURIA
EVALUATION
Dr Tarun Kumar

2. INTRODUCTION
• Is a cardinal sign of renal disease that imparts
diagnostic & prognostic information
• It is associated with HTN,Obesity & Vascular
disease
• Can be used to predict risks of CKD
progression and cardiovascular disease and all
cause mortality in general population.
• That’s why Protein lowering therapies may be
renoprotective & Monitoring proteinuria is a
key aspect of assessing treatment response.

3. Normal Physiology
• In humans ,on the basis of GFR 100 ml/min ,180 L of
primary urine is produced per day from plasma that
contains about 10 kg of protein.However only .01% or
1g of protein passes through glomerular filtration
barrier that further reabsorbed by proximal tubule
• The glomerular filtration barrier(endothelial Cells,the
glomerular basement membrane and podocytes) acts
as a size,shape and charge dependent permselective
molecular sieve .
• Injury to any three layers of filtration barrier leads to
proteinuria (glomerular)

4. • Physiological Proteinuria : < 150 mg in 24 hours for
adults and 140 mg/m2 of body surface for
children.
• The daily physiological proteinuria contains
– mucoprotein (e.g. Tamm–Horsfall glycoprotein(50%),
70 mg),
– blood group-related substances (35 mg),
– albumin (20-30mg),
– Ig (6 mg),
– mucopolysachrides (16 mg),
and very small amounts of other Proteins such as
hormones and enzymes

5. • Types of proteinuria :-
• Four Types: Glomerular, Tubular, Overload, and
Postrenal.
• Glomerular proteinuria : occurs due to injury to
filtration barrier
• Often results in proteinuria >1 g /day
• Tubular proteinuria : occurs due to tubular
damage or dysfunction that inhibits reabsorptive
capacity of proximal tubule
• results in higher amounts of LMW proteins (
alpha1 or beta2 microglobulin,Retinol Binding
Protein ,enzymes & peptides)in urine
• Classic causes Fanconi syndrome & Dent disease

6. • Overflow proteinuria:- is secondary to an increased
production, or release of low-molecular weight proteins,
which are usually reabsorbed by the proximal tubular cells,
• Examples are immunoglobulin light chains in myeloma ,
myoglobin in rhabdomyolysis,lysozyme in leukemia and
hemoglobin in severe intravascular hemolysis.
• Postrenal Proteinuria:- small amounts of protein usually
nonalbumin IgG ,IgA may be excreted in urinary tract in
setting of infection or stones .
• Leucocytes are also commonly present in the urine
sediment

7. Types of Glomerular Proteinuria
1. Functional proteinuria: refers to transient
non Nephrotic proteinuria that can occur
with fever,exercise ,heart failure .
It is usually benign ,
usually asigned to be hemodynamic in origin
& the result of increases in single nephron flow
or pressure

8. 2. Orthostatic Proteinuria: Patient has no
proteinuria in early morning but has low grade
proteinuria in upright position.
Usually less than <1 g/day in tall,thin
adolescents younger than 30 years
Normal Renal function without hematuria &
hypertension

9. 3. Fixed Non- Nephrotic Proteinuria:
Usually caused by Glomerular disease
Less than .5-1 g/day
Prolonged follow up is necessary if significant
proteinuria persists to rule out progression

10. Categorization of Proteinuria
• Table 23.5 Kidney Disease: Improving Global Outcomes (KDIGO)
Guideline: Categories of Proteinuria
1. Normal to Mildly Increased (KDIGO A1) Moderately Increased
(KDIGO A2) AER (mg/24 h) PER (mg/24 h) ACR: mg/mmol mg/g
PCR: mg/mmol mg/g Protein reagent strip <30 <150 <3 <30 <15
<150 Negative to trace 30–300 150–500 3–30 30–300 15–50 150–
500 Trace to + Severely Increased (KDIGO A3) >300 >500 >30 >300
>50 >500 + or greater aRelationships between AER and ACR and
between PER and PCR are based on the assumption that average
creatinine excretion rate is 1.0 g/day or 10 mmol/day (conversions
are rounded for pragmatic reasons). ACR, Albumin-to-creatinine
ratio; AER, albumin excretion rate; PCR, protein-to-creatinine
ratio; PER, protein excretion rate. From Kidney Disease: Improving
Global Outcomes (KDIGO) CKD Work Group. KDIGO 2012 clinical
practice guideline for the evaluation and management of chronic
kidney disease. Kidney Int Suppl. 2013;3:1–150.
Normal to mildly
Increased (KDIGO A1)
Moderately Increased
(KDIGO A2 )
Severly Increased ( KDIGO
A3)
AER(mg/24hr) - <30
PER(mg /24hr)-<150
ACR:
mg/mmol<3
mg/g <30
30-300
150-500
3-30
30-300
>300
>500
>30
>300
PCR:
mg/mmol<15
mg/g <150
Protein Reagent Strip:
negative to trace
15-50
150-500
Trace to 1+
>50
>500
+1 or greater

11. Relation between Urine ACR /PCR into
Total Protein
• 24 hr Urine protein (mg) =
PCR (mg/mol) or ACR (mg/mol) × 10
Considering average creatinine excretion
around 10mmol

12. Limitations of ACR & PCR
• Variability in total body creatinine excretion
• Fluctuations in protein excretion throught the
day
• Due to these two factors their ability to
predict 24hr urinary protein is limited.

13. Quantification of proteinuria
1. Urine Dipstick(Initial Screening)
2. Spot protein to Creatinine ratio
3. Spot Albumin to Creatinine Ratio
4. 24 hr Urine protein- Gold standard

14. Reagent Strip Testing
• Most dipstick reagents are semiquantative
,containing a PH sensitive colorimetric
indicator(Tetrabromophenol Blue) that
changes color when negatively charged
protein bind to it
• Limited sensitivity for nonalbumin & positively
charged proteins

16. Limitations of Dipstick test
• Very dilute urine-False negative
• Concentrated Urine- False positive

17. Methods to measure Urinary total
Protein
Chemical
Biuret
Copper reagent measured
peptide bond
50mg/L
Turbidimetric
Sulfosalicylic acid
Trichloroacetic acid
Addition of precipitant
denatures proteins
Suspension turbidity is
read in densitometer
50-100mg/L
Dye Binding
Coomassie Brilliant Blue
Pyrogallol Red
Dye binds with protein
results in colour change of
indicator which is read by
spectrophotometry
50-100mg/L

18. Biuret methods
• Based on the interaction between copper ions
and the carbamide group of proteins.
• They have the same sensitivity for all proteins.
• The protein in urine must be concentrated
before the biuret reaction occurs.
• Interference from drugs, radiographic contrast
media, and coloured metabolites is minimal

19. Turbidimetric methods
• These methods are among the most frequently
used (e.g.Trichloroacetic acid, sulfosalicylic acid).
However, numerous drugs can
interfere(tolbutamide/penicillins/Naficillin/Radioco
ntrast agents) with this method

20. Dye-binding techniques
• Based on the interaction between proteins and a
dye, which changes colour of indicator (measured
photometrically)
• Coomassie brilliant blue G250 is very sensitive, but
with diluted samples significant deviations from
linearity are possible.
• Moreover, underestimation of tubular proteinuria
and interference from various metabolites, drugs,
and preservative compounds has been observed.
The method is somewhat improved by the addition
of sodium dodecylsulphate.

21. Dye-binding techniques
Pyrogallol red-molybdate method can easily be
implemented on automated analysers. This
method has been improved by the addition of
sodium dodecylsulphate
It is equally sensitive to albumin and globulins, but
falsely low values can result due to tubular /LMW
proteins while falsely high values may derive from
the contamination of the precipitate by plasma
Expanders and Aminoglycoside antibiotics .

22. Methods to measure Urinary Albumin
• Immunoturbidimetry method : most commonly
used based on antibody binding principle
• HPLC: detects both immunoreactive &
nonimmunoreactive albumin
• Nephelometry: Albumin in urine reacts with
specific antialbumin antibody forming light
scattering antigen antibody complexes that can
be measured with a laser nephelometer.
• Double Antibody Radioimmunoassay: Expensive

23. Newer Devices
• Albumin Specific Dipsticks Micral
Test(Germany) & Micro-Bumintest(Indiana)
• Creatinine Test Pad for ACR (CLINITEK System)

24. Factors Influencing accuracy of
proteinuria measurement
Preanalysis phase Analysis Phase
• Total Protein or albumin
measurement
• Assay
• Collection type :
Timed or random
Timing of random
measurement
• Degradation of Protein or
albumin during storage
Adsorption to plastic
Storage Temperature

25. Patient Factors That may Increase
Urinary Protein or Albumin
• Posture (postural proteinuria)
• Urinary Tract Infection
• Hematuria
• High dietary protein intake & High Intensity
Exercise
• Congestive Cardiac failure
• Menstruation or vaginal discharge
• Drugs( NSAIDS)

26. Diagnostic Utility of protein type
• Several studies shown that albumin
predominate in Glomerular disease & LMW
Proteins predominate in Tubulointerstitial
disorders

27. Proteinuria and progression of renal
diseases
• The rate of renal function decline is directly
proportional to severity of proteinuria
• Proteinuria itself causes tubular injury that
leads to tubular atrophy & interstitial fibrosis
• Transudation of protein leads to activation of
glomerular endothelial cells that proliferates &
synthesize Extracellular matrix that further
leads to glomerulosclerosis

28. Proteinuria in Specific population
• Pregnant patients: >300mg /24hrs or PCR
30mg/mol(.3g/g) for diagnosis of
preeclampsia
• Children: 1000mg/m2/day or 40mg/m2/hr or
higher is defined as Nephrotic Range
Proteinuria
• Renal Transplant Recipients: predicts Allograft
loss, cardiovascular risk & death in transplant
patients

29. Symptoms
• In most cases proteinuria detected on a
routine screening & has no symptoms
• If protein loss is severe, pitting edema
develops first around the face & around the
eyes followed by other body parts
• Foamy or Frothing of urine
• Weight gain by fluid retention

30. How to Approach a
patient of Proteinuria

31. History
•Presence of diabetes/Hypertension
•Drug History (NSAIDS/GOLD/Penicillamine )
• Deafness, Family history (Alport’s nephropathy and other familial nephritis),
•Ethnicity (IgA nephropathy more in Asian than black,FSGS more common in black)
•H/o polyuria/nocturia for tubular disorders
•Blood transfusion; drug abuse; sexual orientation and partners (HIV, hepatitis B & C,
syphilis)
•Malar or skin rash, oral ulcers,joint pain, alopecia (SLE, other autoimmune disorders)
•Low grade fever/rash /joint paint /abdominal pain/bleeding
•Hemoptysis for pulmonary renal syndromes
•Sinusitis, sterile otitis, neurological deficit, parasthesia (Fabry’s disease)
• Episodes of gross or microscopic hematuria after sorethroat (PSGN,IgA nephropathy)
•Backache & unexplained renal failure ( Multiple Myeloma)
•Cough, weight loss, breast mass ,old kochs(malignancy, Amyloidosis, secondary
membranous nephropathy),
•Childhood UTIs(reflux nephropathy).

32. Warning Sign in case of Glomerular Proteinuria:
• Check for any renal dysfunction
• Check for presence of active sediments
• Check for Hypertension

33. investigations
1. Urine Dipstick followed by 24 hr Urine proteins
2. ACR & PCR
3. CBC
4. RFT/LFT / SCaPo4/Sprotein/Albumin/Lipid
Profile/Blood Sugar/PT/INR/HbAIC
5. Viral Markers HIV /HbsAg/HCV
6. Ultrasonography for the kidney size & CMD
7. X-Ray Chest (Wegener’s granulomatosis, lung
diseases causing amyloidosis)
8. Serum as well as urinary electrophoresis

34. Additional Tests
•Antinuclear antibodies,dsDNA (lupus), ANCA
(pauci-immune vasculitis), PLA2R Levels
•C3-C4 (endocarditis, post streptococcal GN, lupus,
cryoglobulinemia)
•Anti hyalouronidase, anti-Dnase B, ASO
Titre(PSGN)
•Antiglomerular basement membrane antibody
(good pasture’s disease),
• Rule out malignancies in elderly
•Renal Biopsy for histological diagnosis

35. Summary
• A dipstick urine test should be used for initial
screening of Proteinuria
•24 hr Urine Collection for protein is Gold Standard
• ACR & PCR are the less combersome & quick test
to access proteinuria
• The amount of proteinuria can also differentiate
glomerular from non-glomerular proteinuria.
•Thorough history & investigation are done for
prompt diagnosis & further treatment.

36. Thank you