A 58-year-old man has had 2 months of sinusitis with bloody nasal crusts, a cough and, recently, ankle swelling. His creatinine has risen from 1.1 to 3.4 mg/dL [97 to 301 µmol/L] in 3 weeks. Urine: protein 2+, blood 3+, many dysmorphic red cells and red cell casts. Serum C3 and C4 are normal, ANA and anti-GBM antibody are negative, and ASO and anti-DNase B are normal. Indirect immunofluorescence shows a cytoplasmic ANCA pattern, and the PR3-ANCA immunoassay is strongly positive. The most likely diagnosis is:

Granulomatosis with polyangiitis

Post-streptococcal glomerulonephritis

A 7-year-old has facial swelling and dark urine 3 weeks after impetigo. Results: urine blood 3+, red cell casts, serum C3 low, C4 normal, ASO titer normal, anti-DNase B raised. The most likely diagnosis is:

Post-streptococcal glomerulonephritis

Membranoproliferative glomerulonephritis

Urinary disease states

16 ASCP MLS practice questions on Urinary disease states, part of Urinalysis and Body Fluids. The first 16 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Hard
A 6-day-old boy who was well at birth now feeds poorly, is increasingly lethargic and has episodes of rigid, arched posturing. He has a metabolic acidosis, and his plasma glucose is 68 mg/dL [3.8 mmol/L]. The nurses note that his diapers smell like burnt sugar. Urine: SG 1.020, pH 5.5, ketones moderate, glucose pad negative, Clinitest negative. A 2,4-dinitrophenylhydrazine (DNPH) test gives a heavy yellow precipitate. Liver tests and the clotting screen are normal, and he is not jaundiced. Which disorder is most likely?
1. AClassic galactosemia
2. BIsovaleric acidemia
3. CMaple syrup urine disease
4. DHereditary tyrosinemia type 1
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Answer: C · Maple syrup urine disease
A newborn who becomes lethargic with abnormal posturing after feeds begin, with ketonuria and acidosis, suggests an inborn error of amino acid or organic acid metabolism. The burnt-sugar (maple syrup) odor and a strongly positive DNPH test for alpha-keto acids point to maple syrup urine disease. A defect in branched-chain alpha-keto acid dehydrogenase lets leucine, isoleucine and valine and their keto acids build up, and leucine is the main neurotoxin. The negative Clinitest argues against galactosemia, and the odor and normal liver tests argue against the other disorders. The diagnosis is confirmed by plasma amino acids showing raised branched-chain amino acids and alloisoleucine.
- A: Galactosemia gives a positive copper reduction test with a negative glucose pad, but the Clinitest is negative.
- B: Isovaleric acidemia gives a sweaty-feet odor, and isovaleric acid is not a keto acid that reacts with DNPH.
- D: Tyrosinemia type 1 presents with liver failure and a cabbage-like odor, and his liver tests are normal.
Question 2 · Hard
A 58-year-old man has had 2 months of sinusitis with bloody nasal crusts, a cough and, recently, ankle swelling. His creatinine has risen from 1.1 to 3.4 mg/dL [97 to 301 µmol/L] in 3 weeks. Urine: protein 2+, blood 3+, many dysmorphic red cells and red cell casts. Serum C3 and C4 are normal, ANA and anti-GBM antibody are negative, and ASO and anti-DNase B are normal. Indirect immunofluorescence shows a cytoplasmic ANCA pattern, and the PR3-ANCA immunoassay is strongly positive. The most likely diagnosis is:
1. AAnti-GBM (Goodpasture) disease
2. BIgA vasculitis nephritis
3. CGranulomatosis with polyangiitis
4. DPost-streptococcal glomerulonephritis
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Answer: C · Granulomatosis with polyangiitis
Red cell casts, dysmorphic red cells and a creatinine that triples in weeks indicate a rapidly progressive glomerulonephritis. Normal C3 and C4 argue against the immune-complex diseases that consume complement, such as post-streptococcal and lupus nephritis, and a negative anti-GBM antibody excludes Goodpasture disease. Upper airway disease with a strongly positive PR3-ANCA in a cytoplasmic (c-ANCA) pattern points to granulomatosis with polyangiitis, a pauci-immune small-vessel vasculitis. The urine sediment shows that the kidneys are involved and that treatment is urgent. Kidney biopsy typically shows necrotizing crescentic glomerulonephritis with few or no immune deposits.
- A: Anti-GBM disease would show anti-GBM antibody, which is negative.
- B: IgA vasculitis causes purpura with joint or abdominal pain and is ANCA-negative.
- D: Post-streptococcal disease lowers C3 and raises ASO or anti-DNase B, and all of these are normal.
Question 3 · Medium
A child with smoky urine and puffy eyes two weeks after a sore throat has dysmorphic red cells and red cell casts in the urine sediment. Where is the bleeding coming from?
1. AThe glomeruli
2. BThe urethra
3. CThe renal pelvis from a stone
4. DThe bladder mucosa
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Answer: A · The glomeruli
Red cell casts form only inside the nephron, when red cells that have passed through damaged glomeruli are trapped in uromodulin in the tubules. Dysmorphic red cells also point to a glomerular source. The history fits post-streptococcal glomerulonephritis. Lower urinary tract bleeding gives normal-shaped red cells and no casts.
- B: Urethral bleeding cannot produce casts.
- C: A stone in the renal pelvis bleeds below the tubules, so no red cell casts form.
- D: Bladder bleeding gives intact red cells but no casts, because casts form only in the tubules.
Question 4 · Medium
Plasma glucose 88 mg/dL [4.9 mmol/L], urine glucose 2+, generalized aminoaciduria, phosphaturia with a low serum phosphate, and a low serum bicarbonate. These results are most consistent with:
1. AIsolated renal glycosuria
2. BCystinuria
3. CDiabetes mellitus
4. DFanconi syndrome
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Answer: D · Fanconi syndrome
Fanconi syndrome is a general failure of proximal tubular reabsorption. Glucose, amino acids, phosphate and bicarbonate are lost in the urine despite normal plasma levels, giving glycosuria with a normal blood glucose and a proximal renal tubular acidosis. Causes include cystinosis in children and, in adults, myeloma light chains, heavy metals and drugs such as tenofovir. The phosphate loss can cause rickets or osteomalacia.
- A: Isolated renal glycosuria affects glucose transport only.
- B: Cystinuria affects only cystine and the dibasic amino acids, not glucose or phosphate.
- C: Diabetes mellitus causes glycosuria through a high plasma glucose.
Question 5 · Hard
A 7-year-old has facial swelling and dark urine 3 weeks after impetigo. Results: urine blood 3+, red cell casts, serum C3 low, C4 normal, ASO titer normal, anti-DNase B raised. The most likely diagnosis is:
1. APost-streptococcal glomerulonephritis
2. BMembranoproliferative glomerulonephritis
3. CIgA nephropathy
4. DLupus nephritis
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Answer: A · Post-streptococcal glomerulonephritis
Post-streptococcal glomerulonephritis follows throat or skin infection with nephritogenic group A streptococci after a latent period, about 1 to 3 weeks after pharyngitis and 3 to 6 weeks after impetigo. Immune complexes activate complement mainly through the alternative pathway, so C3 is low while C4 is usually normal. After skin infections the ASO titer often stays low, so anti-DNase B is the better marker. C3 normally recovers within about 8 weeks.
- B: Membranoproliferative disease keeps C3 low beyond 8 weeks; the timing and anti-DNase B here point to streptococci.
- C: IgA nephropathy gives hematuria within days of infection, with normal complement.
- D: Lupus nephritis lowers both C3 and C4 and is rare at this age without systemic features.
Question 6 · Medium
A 23-year-old man notices cola-colored urine one day after a sore throat begins. Serum C3 is normal, and the urine contains dysmorphic red cells. Which disease is most likely?
1. ALupus nephritis
2. BMinimal change disease
3. CIgA nephropathy
4. DPost-streptococcal glomerulonephritis
Answer and explanation in LearnFree account
Question 7 · Medium
A 27-year-old man has hemoptysis, a rising creatinine and red cell casts. Kidney biopsy shows linear IgG along the glomerular basement membrane. The antibody is directed against:
1. ANeutrophil myeloperoxidase
2. BPhospholipase A2 receptor
3. CDouble-stranded DNA
4. DType IV collagen of basement membranes
Answer and explanation in LearnFree account
Question 8 · Hard
A 64-year-old woman develops fever, a rash and a rising creatinine 10 days after starting a penicillin. Urine shows many white cells and white cell casts, a Hansel stain shows 9% eosinophils, and the urine culture is negative. The most likely diagnosis is:
1. AAcute pyelonephritis
2. BAcute interstitial nephritis
3. CAcute glomerulonephritis
4. DAcute tubular necrosis
Answer and explanation in LearnFree account
Question 9 · Medium
A urine sample turns black after standing for several hours. The glucose oxidase strip is negative, but a copper reduction test is positive. The most likely disorder is:
1. AAlkaptonuria
2. BGalactosemia
3. CPhenylketonuria
4. DMalignant melanoma (melanuria)
Answer and explanation in LearnFree account
Question 10 · Hard
A 19-year-old with recurrent kidney stones has hexagonal crystals in acidic urine and a positive cyanide-nitroprusside test. What is the underlying defect?
1. APoor tubular reabsorption of cystine and dibasic amino acids
2. BLysosomal storage of cystine within tissue cells
3. COverproduction of cystine by the liver
4. DFailure to break down homocysteine
Answer and explanation in LearnFree account
Question 11 · Hard
A 25-year-old woman with joint pain and a facial rash has urine protein 3+ and blood 3+. The sediment shows red cell casts, white cell casts, and waxy and broad casts. Serum C3 and C4 are both low, and anti-dsDNA is positive. Which disease is most likely?
1. AIgA nephropathy
2. BLupus nephritis
3. CAnti-GBM disease
4. DPost-streptococcal glomerulonephritis
Answer and explanation in LearnFree account
Question 12 · Hard
A 70-year-old man is oliguric two days after major surgery. Urine sodium 60 mmol/L, plasma sodium 140 mmol/L, urine creatinine 40 mg/dL [3,536 µmol/L], plasma creatinine 4.0 mg/dL [354 µmol/L]. What is the fractional excretion of sodium (FENa), and what does it suggest?
1. A0.43%; prerenal azotemia
2. B4.3%; acute tubular necrosis
3. C0.43%; acute tubular necrosis
4. D4.3%; prerenal azotemia
Answer and explanation in LearnFree account
Question 13 · Easy
In adults, nephrotic syndrome is defined in part by urine protein excretion above about:
1. A30 mg/day
2. B3.5 g/day
3. C300 mg/day
4. D150 mg/day
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Question 14 · Easy
The most common cause of nephrotic syndrome in young children is:
1. AMinimal change disease
2. BIgA nephropathy
3. CMembranous nephropathy
4. DPost-streptococcal glomerulonephritis
Answer and explanation in LearnFree account
Question 15 · Hard
A 56-year-old man has edema, urine protein 6.2 g/day, serum albumin 2.1 g/dL [21 g/L] and no red cell casts. Serum anti-phospholipase A2 receptor (PLA2R) antibody is positive. Which disease is most likely?
1. AAnti-GBM disease
2. BMinimal change disease
3. CPrimary membranous nephropathy
4. DIgA nephropathy
Answer and explanation in LearnFree account
Question 16 · Medium
A healthy teenager's afternoon urine is 1+ for protein, but a specimen collected immediately on waking is negative. What is the most likely explanation?
1. AOverflow (prerenal) proteinuria
2. BEarly nephrotic syndrome
3. COrthostatic (postural) proteinuria
4. DTubular proteinuria
Answer and explanation in LearnFree account

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Urinary disease states

A child with smoky urine and puffy eyes two weeks after a sore throat has dysmorphic red cells and red cell casts in the urine sediment. Where is the bleeding coming from?

Plasma glucose 88 mg/dL [4.9 mmol/L], urine glucose 2+, generalized aminoaciduria, phosphaturia with a low serum phosphate, and a low serum bicarbonate. These results are most consistent with:

A 7-year-old has facial swelling and dark urine 3 weeks after impetigo. Results: urine blood 3+, red cell casts, serum C3 low, C4 normal, ASO titer normal, anti-DNase B raised. The most likely diagnosis is:

A 23-year-old man notices cola-colored urine one day after a sore throat begins. Serum C3 is normal, and the urine contains dysmorphic red cells. Which disease is most likely?

A 27-year-old man has hemoptysis, a rising creatinine and red cell casts. Kidney biopsy shows linear IgG along the glomerular basement membrane. The antibody is directed against:

A 64-year-old woman develops fever, a rash and a rising creatinine 10 days after starting a penicillin. Urine shows many white cells and white cell casts, a Hansel stain shows 9% eosinophils, and the urine culture is negative. The most likely diagnosis is:

A urine sample turns black after standing for several hours. The glucose oxidase strip is negative, but a copper reduction test is positive. The most likely disorder is:

A 19-year-old with recurrent kidney stones has hexagonal crystals in acidic urine and a positive cyanide-nitroprusside test. What is the underlying defect?

A 25-year-old woman with joint pain and a facial rash has urine protein 3+ and blood 3+. The sediment shows red cell casts, white cell casts, and waxy and broad casts. Serum C3 and C4 are both low, and anti-dsDNA is positive. Which disease is most likely?

A 70-year-old man is oliguric two days after major surgery. Urine sodium 60 mmol/L, plasma sodium 140 mmol/L, urine creatinine 40 mg/dL [3,536 µmol/L], plasma creatinine 4.0 mg/dL [354 µmol/L]. What is the fractional excretion of sodium (FENa), and what does it suggest?

In adults, nephrotic syndrome is defined in part by urine protein excretion above about:

The most common cause of nephrotic syndrome in young children is:

A 56-year-old man has edema, urine protein 6.2 g/day, serum albumin 2.1 g/dL [21 g/L] and no red cell casts. Serum anti-phospholipase A2 receptor (PLA2R) antibody is positive. Which disease is most likely?

A healthy teenager's afternoon urine is 1+ for protein, but a specimen collected immediately on waking is negative. What is the most likely explanation?