Diagnostic Testing in Nephrology

Question 1

Two things you can check on a urinalysis is white cells and nitrites. What is the significance of both

Answer 1

1. ) White cells: Can only see if you do microscopy on the urinalysis, otherwise do dipstick to see leukocyte esterase
2. ) Nitrites: Indicates presence of gram negative bacteria - can be done on dipstick

Question 2

Some minor protein excretion is expected for the kidneys. What amount if considered normal and what are these proteins called

Answer 2

1. ) Tamm-Horsfall proteins - 30 to 50 mg over 24 hours

2. ) Transient proteinuria is benign and can represent orthostatic proteinuria (proteins from standing)

Question 3

There are two tests to evaluate protein excretion in a day, what are they

Answer 3

1. ) Single protein to creatinine ratio on urinalysis - anytime you have proteinuria do this test INITIALLY
2. ) 24 hour urine collection of protein

Both equal in accuracy, but (2) rarely performed

Question 4

A patient with myeloma presents with specific proteins in their urine. What are they and how do we diagnose this

Answer 4

Bence Jones proteins - not seen in dipstick so use immunoelectrophoresis instead

Question 5

White blood cells are important in urinalysis because different cells relate to different pathologies. Neutrophils indicate infection, while eosinophils indicate allergic or acute interstitial nephritis that is NOT NSAIDs. What stain can you do of the urine that will detect eosinophils

Answer 5

Wright and Hansel stain - do this if you suspect allergic interstitial nephritis

Question 6

What are some causes of hematuria in the urine (six causes)

Answer 6

1. ) Glomerulonephritis (hint - blood cells are dysmorphic)
2. ) Stones or cancer
3. ) Coagulopathy
4. ) Infections - Cystitis/pyelonephritis - neutrophil WBCs
5. ) Treatments - cyclophosphamide causing hemorrhagic cystitis
6. ) Trauma

However, must do microscopy to distinguish if there actually is blood or if its hemoglobin/myoglobin (false positives) - never do intravenous pyelogram because slow

Question 7

What is a short algorithm for hematuria

Answer 7

1. ) See hematuria
2. ) Do microscopic evaluation if it is actually RBC’s
3. ) If no infection/trauma, do renal ultrasound/CT and bladdar ultrasound
4. ) If renal ultrasound/CT negative and bladdar ultrasound positive, then possible mass and need to do cystoscopy for possible biopsy

Question 8

For urinary casts, you can get red cell casts, white cell casts, eosinophil casts, hyaline casts, waxy casts, and muddy brown casts. What do hyaline casts represent

Answer 8

Dehydration state where normal tamm-horsfall proteins condense into casts

Question 9

What is the most accurate test for anything in the bladdar

Answer 9

Cystoscopy