Color
Normal color varies from pale light yellow to dark amber
See Abnormally colored urine
Normal color varies from pale light yellow to dark amber
See Abnormally colored urine
Clarity/turbidity
Determined by substances in urine, including cellular debris, casts, crystals, bacteria, proteinuria, vaginal discharge, sperm
Determined by substances in urine, including cellular debris, casts, crystals, bacteria, proteinuria, vaginal discharge, sperm
pH
Slightly acidic urine is normal
Any acid-base abnormalities affects urinary pH
Diet can affect pH
Useful in evaluation stones, infection, RTA
Stones: alkaline (calcium oxalate/calcium phosphate, magnesium-ammonium phosphate, staghorn) vs acidic (uric acid, cysteine)
UTI: proteus and klebsiella produce alkaline urine
Slightly acidic urine is normal
Any acid-base abnormalities affects urinary pH
Diet can affect pH
Useful in evaluation stones, infection, RTA
Stones: alkaline (calcium oxalate/calcium phosphate, magnesium-ammonium phosphate, staghorn) vs acidic (uric acid, cysteine)
UTI: proteus and klebsiella produce alkaline urine
Stones: alkaline (calcium oxalate/calcium phosphate, magnesium-ammonium phosphate, staghorn) vs acidic (uric acid, cysteine)
UTI: proteus and klebsiella produce alkaline urine
Specific gravity
Represents kidney's ability to concentrate urine; often reflective of hydration status
Low values can be seen in patients with impaired urinary concentrating ability (i.e. diabetes insipidus, sickle cell nephropathy, acute tubular necrosis)
High values can be due to elevated protein or ketoacids
Specific gravity should be considered in detection of pediatric UTI
The higher the concentration of the urine, when in the presence of negative LE, the higher the negative predictive value of UTI
At threshold of greater than or equal to 5 WBCs per HPF in microscopic UA
Represents kidney's ability to concentrate urine; often reflective of hydration status
Low values can be seen in patients with impaired urinary concentrating ability (i.e. diabetes insipidus, sickle cell nephropathy, acute tubular necrosis)
High values can be due to elevated protein or ketoacids
Specific gravity should be considered in detection of pediatric UTI
The higher the concentration of the urine, when in the presence of negative LE, the higher the negative predictive value of UTI
At threshold of greater than or equal to 5 WBCs per HPF in microscopic UA
The higher the concentration of the urine, when in the presence of negative LE, the higher the negative predictive value of UTI
At threshold of greater than or equal to 5 WBCs per HPF in microscopic UA
Glucose
Glucosuria is due to high blood glucose or decreased kidney threshold concentration
Typically seen in diabetics or pregnant patients
Glucosuria is due to high blood glucose or decreased kidney threshold concentration
Typically seen in diabetics or pregnant patients
Ketones
Typically seen with uncontrolled diabetes, Diabetic ketoacidosis, severe exercise, starvation, vomiting, pregnancy
Typically seen with uncontrolled diabetes, Diabetic ketoacidosis, severe exercise, starvation, vomiting, pregnancy
Nitrite
90% specific but 50% sensitive in detecting gram negative bacteria that converts nitrate to nitrite
A positive test suggest bacteria but a negative test cannot rule out UTI
90% specific but 50% sensitive in detecting gram negative bacteria that converts nitrate to nitrite
A positive test suggest bacteria but a negative test cannot rule out UTI
Leukocyte Esterase
Enzyme within WBC that is released when WBCs lyse
70% sensitive and 50% specific for detecting WBCs (pyuria)
Enzyme within WBC that is released when WBCs lyse
70% sensitive and 50% specific for detecting WBCs (pyuria)
Bilirubin
Increased urobilirubin associated with excessive hemolysis, liver disease, constipation, intestinal bacterial overgrowth
Decreased urobilirubin associated with obstructive biliary disease and severe cholestasis
Increased urobilirubin associated with excessive hemolysis, liver disease, constipation, intestinal bacterial overgrowth
Decreased urobilirubin associated with obstructive biliary disease and severe cholestasis
Proteins
Urine dipstick become positive the protein >300-500mg/d
Trace - 10-30mg/dl
1+ - 30mg/dl
2+ - 100mg/dl
3+ - 300 mg/dl
4+ - >1000mg/dl
Etiology
Transient proteinuria: CHF, fever, exercise, seizure, stress
Persistent proteinuria: nephrotic syndrome, glomerulonephritis, ATN, AIN, Falcon syndrome, multiple myeloma, myoglobinuria
Urine dipstick become positive the protein >300-500mg/d
Trace - 10-30mg/dl
1+ - 30mg/dl
2+ - 100mg/dl
3+ - 300 mg/dl
4+ - >1000mg/dl
Etiology
Transient proteinuria: CHF, fever, exercise, seizure, stress
Persistent proteinuria: nephrotic syndrome, glomerulonephritis, ATN, AIN, Falcon syndrome, multiple myeloma, myoglobinuria
Trace - 10-30mg/dl
1+ - 30mg/dl
2+ - 100mg/dl
3+ - 300 mg/dl
4+ - >1000mg/dl
Transient proteinuria: CHF, fever, exercise, seizure, stress
Persistent proteinuria: nephrotic syndrome, glomerulonephritis, ATN, AIN, Falcon syndrome, multiple myeloma, myoglobinuria
Blood
If more than 3RBCs, urine dipstick is positive for blood
Does not detect where the blood is coming from
Can be due to hematuria, hemoglobinuria, myoglobinuria, contamination
Blood+/RBC+ → hematuria
Blood+/RBC- → myoglobinuria (rhabdomyolysis, renal failure) or hemoglobinuria (infection, transfusion-related reaction, paroxysmal nocturnal hemoglobinuria)
If more than 3RBCs, urine dipstick is positive for blood
Does not detect where the blood is coming from
Can be due to hematuria, hemoglobinuria, myoglobinuria, contamination
Blood+/RBC+ → hematuria
Blood+/RBC- → myoglobinuria (rhabdomyolysis, renal failure) or hemoglobinuria (infection, transfusion-related reaction, paroxysmal nocturnal hemoglobinuria)
Can be due to hematuria, hemoglobinuria, myoglobinuria, contamination
Blood+/RBC+ → hematuria
Blood+/RBC- → myoglobinuria (rhabdomyolysis, renal failure) or hemoglobinuria (infection, transfusion-related reaction, paroxysmal nocturnal hemoglobinuria)
WBCs
Elevated WBCs indicate infection, inflammation or contamination
Elevated WBCs indicate infection, inflammation or contamination
RBCs
Microscopic hematuria defined as 3RBCs/hpf or more
Transient hematuria in young patients is typically benign. In older patients >50yo, warrants further work-up for underlying malignancy
Persistent hematuria always warrants further work-up
Renal: glomerular (proteinuria, RBC casts, dysmorphic RBCs) vs nonglomerular (no RBC casts or dysmorphic RBCs)
Extrarenal: tumors, stones, BPH, infections (pyelonephritis, cystitis, prostatitis, urethritis), schistosomiasis, foley trauma, anticoagulants, chemotherapy
Microscopic hematuria defined as 3RBCs/hpf or more
Transient hematuria in young patients is typically benign. In older patients >50yo, warrants further work-up for underlying malignancy
Persistent hematuria always warrants further work-up
Renal: glomerular (proteinuria, RBC casts, dysmorphic RBCs) vs nonglomerular (no RBC casts or dysmorphic RBCs)
Extrarenal: tumors, stones, BPH, infections (pyelonephritis, cystitis, prostatitis, urethritis), schistosomiasis, foley trauma, anticoagulants, chemotherapy
Renal: glomerular (proteinuria, RBC casts, dysmorphic RBCs) vs nonglomerular (no RBC casts or dysmorphic RBCs)
Extrarenal: tumors, stones, BPH, infections (pyelonephritis, cystitis, prostatitis, urethritis), schistosomiasis, foley trauma, anticoagulants, chemotherapy
Epithelial Cells
Generally, 15-20 squamous cells or more indicates contamination
Hyaline casts - nonspecific
Red cell casts - nearly diagnostic of glomerulonephritis or vasculitis
White cell casts - tubulointerstitial nephritis, acute pyelonephritis, renal tuberculosis, vaginal infection
Muddy-brown granular casts - diagnostic of acute tubular necrosis
Waxy and broad casts - advanced renal failure
Fatty casts - nephrotic syndrome
Generally, 15-20 squamous cells or more indicates contamination
Hyaline casts - nonspecific
Red cell casts - nearly diagnostic of glomerulonephritis or vasculitis
White cell casts - tubulointerstitial nephritis, acute pyelonephritis, renal tuberculosis, vaginal infection
Muddy-brown granular casts - diagnostic of acute tubular necrosis
Waxy and broad casts - advanced renal failure
Fatty casts - nephrotic syndrome
Crystals
May be normal
Calcium oxalate crystals - ethylene glycol ingestion
Uric acid crystals - tumor lysis syndrome, gout
Cystine crystals - cystinuria
Magnesium ammonium phosphate and triple phosphate crystals - UTI caused by Proteus, Klebsiella
May be normal
Calcium oxalate crystals - ethylene glycol ingestion
Uric acid crystals - tumor lysis syndrome, gout
Cystine crystals - cystinuria
Magnesium ammonium phosphate and triple phosphate crystals - UTI caused by Proteus, Klebsiella
Bacteria
Generally due to infection or contamination
If positive for nitrites, leukocyte esterase and bacteria - highly suggestive of UTI
If significant amount of squamous epithelial cells - may indicate contamination
Urine culture should be obtained if UTI suspected
Generally, >100K/mL of a single organism reflects significant bacteriuria
Generally due to infection or contamination
If positive for nitrites, leukocyte esterase and bacteria - highly suggestive of UTI
If significant amount of squamous epithelial cells - may indicate contamination
Urine culture should be obtained if UTI suspected
Generally, >100K/mL of a single organism reflects significant bacteriuria
Generally, >100K/mL of a single organism reflects significant bacteriuria
Yeast
Generally due to infection or contamination
Generally due to infection or contamination
Urine analysis
Renal ultrasound
Bladder ultrasound
Urine toxicology screen
Bladder lavage
Mini mental status exam
Fundoscopic exam
Pelvic ultrasound 