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Question and answer links
- W1: A 16-year-old swimmer, 188 cm tall (above the 95th height percentile), has a BP of 134/78 on three visits with a correct · Answer
- W2: Which urine sample is most likely to give a falsely positive dipstick protein? · Answer
- Q3: Ethan, 16, came straight from two hours of basketball. His dipstick shows specific gravity 1.030, protein 2+ and trace b · Answer
- Q4: Ethan's first-morning urine has no protein (UPCR 0.08 g/g) but his 4 p.m. sample does (UPCR 0.46 g/g); the morning micro · Answer
- Q5: If you were thinking "a benign orthostatic finding — reassure him and close the chart," and you then learn that both new · Answer
- Q6: Walt, 62, has had two episodes of painless gross hematuria with clots. He has 40 pack-years of smoking, takes apixaban, · Answer
- Q7: A father and daughter have slowly progressive CKD, little protein or blood in the urine, and a family history of early g · Answer
Session S3 · 2026-10-28 · supplementary · 20 min Anchor: Protein and blood on an adolescent's sports-physical urine, and gross hematuria in his grandfather · Integrates: adolescent BP thresholds, dipstick pitfalls, glomerular vs urologic hematuria, hematuria routing by age One-line hook: A sports-physical dipstick hands you two findings in one cup, and a family dinner hands you a third. Each needs a different next step, and the urine itself tells you which. Self-study after Session 3; commit to each answer before you open it.
Learning Objectives
Answers for this section: W1 · W2 · Q3 · Q4 · Q5 · Q6 · Q7
- Classify an adolescent's BP with the static thresholds that apply from age 13 (the cuff-size error that inflates it is discussed, not tested).
- Name the protein pad's false positives and separate transient, orthostatic and persistent proteinuria with a first-morning specimen.
- Confirm microscopic hematuria on properly collected specimens and sort glomerular from urologic bleeding by red-cell shape, protein and age.
- Recognize when a family history changes the meaning of persistent glomerular hematuria, and keep a teenager with glomerular bleeding out of the urologic pathway (the audiometry, eye exam and genetics referral that follow are discussed, not tested).
- Route painless gross hematuria in an older smoker to CT urography and cystoscopy, without blaming an anticoagulant or an unproven UTI.
Warm-Up (individual commit before the case)
Answers for this section: W1 · W2
W1A tall 16-year-old's blood pressure
A 16-year-old swimmer, 188 cm tall (above the 95th height percentile), has a BP of 134/78 on three visits with a correctly sized cuff. How is his BP classified?
Normal, because hypertension in adults does not begin until 140/90
Elevated BP, because percentile thresholds still determine the category until age 18
Stage 1 hypertension, because from age 13 the static 130/80 line applies
Normal for a trained athlete, because conditioning raises resting systolic BP
Show answer and explanation · Link to this question
Correct answer: C
Learning point: From 13 on, the AAP 2017 guideline stages blood pressure with the adult cut-points rather than the percentile tables: elevated 120–129/<80, stage 1 130–139/80–89, stage 2 140/90 or higher. His 134 is in the stage 1 office-BP category. Persistent stage 1 readings on three visits call for ambulatory BP monitoring to confirm hypertension; height does not change the adolescent category. Why not the others: A — 140/90 is stage 2, not the start of hypertension; B — percentile staging stops at 13; D — athletes are staged on the same lines as everyone else. Course reading: Evidence for this case
W2When the protein pad lies
Which urine sample is most likely to give a falsely positive dipstick protein?
A very dilute sample, specific gravity 1.003, after a large water load
A sample carrying immunoglobulin light chains from a myeloma clone
An acidic first-morning sample, pH 5.0, from a well-hydrated teenager
A sample contaminated by a chlorhexidine-containing cleanser
Show answer and explanation · Link to this question
Correct answer: D
Learning point: Chlorhexidine contamination can produce an analytical false-positive protein reaction. The pad mainly detects albumin concentration, so dilute urine or non-albumin proteins can instead yield a falsely reassuring result. Exercise can cause genuine transient proteinuria and concentrated urine can increase the measured protein concentration; neither should be confused with a proven analytical false positive. Confirm an unexpected result with a clean specimen and quantitative protein-to-creatinine or albumin-to-creatinine ratio. Why not the others: A — dilute urine makes the pad falsely negative; B — the albumin-sensitive pad may under-detect light chains, causing a false negative; C — acidic urine does not raise the reading, and a first-morning sample is the specimen you want. Course reading: Evidence for this case
Part 1 — Presentation
Answers for this section: Q3
August, a family medicine clinic. Ethan is 16, 6 feet 3 inches tall, and here for his pre-participation basketball physical. He came straight from a two-hour open gym. He feels well: no swelling, no foamy or dark urine, no recent illness, no supplements and no NSAIDs this month. He hears conversation normally and has never had a urine test. His mother, Laura, drove him and is waiting in the lobby.
Vitals: BP 132/80 (automated wall unit, standard adult cuff) · HR 58 · RR 14 · T 36.7 °C · weight 84 kg · height 190.5 cm.
Exam: Lean and muscular. No edema, no rash. Heart, lungs and abdomen normal.
| Drug | Dose | Route | Frequency | Indication |
|---|---|---|---|---|
| None | — | — | — | No prescription or over-the-counter medicines; no supplements |
The clinic's routine dipstick: specific gravity 1.030, pH 6.5, protein 2+, blood trace, leukocyte esterase and nitrite negative.
Q32+ protein at a sports physical
Ethan, 16, came straight from two hours of basketball. His dipstick shows specific gravity 1.030, protein 2+ and trace blood; he feels well and has no edema. What is the best next step?
A first-morning protein-to-creatinine ratio, plus fresh-sample microscopy for the blood
Hold him out of basketball until a nephrologist has seen him and reviewed a 24-hour urine
A 24-hour urine protein and a renal ultrasound now, before he is cleared to play this season
Nothing now; athletes often show protein after practice, so repeat the dipstick next year
Show answer and explanation · Link to this question
Correct answer: A
Learning point: One daytime dipstick after exercise cannot separate three different things: transient proteinuria (exercise, fever, stress — gone within a day or two), orthostatic proteinuria (protein made only when upright, common in tall, thin young men and benign), and persistent proteinuria from kidney disease. A first-morning specimen — urine made lying down, overnight, at rest — is the key: if its protein-to-creatinine ratio is normal, the daytime protein was postural or transient, and a daytime sample on a rest day tells which. The trace blood is a separate question that only a microscope answers. Why not the others: B — a dipstick finding in a well teenager is not yet a diagnosis, and benching him tests nothing; C — a 24-hour urine and imaging come after a persistent abnormality is confirmed, not before; D — a positive pad is repeated properly now, not ignored for a year. Course reading: Evidence for this case
Part 2 — Data
Answers for this section: Q4
Four days later, after a rest day, Ethan brings a first-morning sample and leaves a second one at 4 p.m. after a school day with no practice. The nurse repeats his BP with a large adult cuff — his mid-arm circumference is 35 cm — after five minutes seated: 124/74. The wall unit's standard cuff was too small for his arm, and an undersized cuff reads high. At 16, 124/74 sits in the "elevated" band (120–129/<80): rechecked at future visits, not hypertension.
| Test | First-morning | 4 p.m., upright, no exercise | Reference range |
|---|---|---|---|
| Specific gravity / pH | 1.024 / 6.0 | 1.018 / 6.5 | 1.005–1.030 / 4.5–8.0 |
| Dipstick protein | negative | 1+ | negative |
| Urine protein-to-creatinine ratio | 0.08 g/g | 0.46 g/g | <0.2 g/g |
| Dipstick blood | 1+ | 1+ | negative |
| RBC, fresh specimen read within 30 minutes | 8–10/hpf; most dysmorphic; acanthocytes about 6% of red cells | not repeated | 0–2/hpf; acanthocytes <5% |
| RBC casts / WBC | none / 0–2/hpf | not repeated | none / 0–5/hpf |
| Serum creatinine | 0.8 mg/dL | — | 0.6–1.2 mg/dL |
Q4Two findings, one cup
Ethan's first-morning urine has no protein (UPCR 0.08 g/g) but his 4 p.m. sample does (UPCR 0.46 g/g); the morning microscopy shows 8–10 RBC/hpf, most of them dysmorphic, with about 6% acanthocytes and no casts. His creatinine is 0.8 and his BP 124/74 with a correctly sized cuff. Which statement is correct?
Orthostatic proteinuria explains both findings, so he is cleared and needs no further urine tests
Hematuria at 16 needs CT urography and cystoscopy to exclude a bladder or kidney tumor
The protein is orthostatic and benign; the blood is real and glomerular — repeat microscopy twice
Protein plus blood means IgA nephropathy; start an ACE inhibitor and refer him for a kidney biopsy
Show answer and explanation · Link to this question
Correct answer: C
Learning point: Protein that appears upright and vanishes overnight is orthostatic proteinuria — generally benign, with periodic blood pressure and urine follow-up. The blood is a separate finding: his 8–10 RBC/hpf exceed the supplied laboratory reference range, and dysmorphic red cells with acanthocytes strongly support a glomerular source. One specimen is not a pattern, and exercise can cause transient hematuria — so repeat microscopy on two more fresh specimens, and ask who else in the family has blood in the urine. Why not the others: A — posture explains protein, not dysmorphic red cells; B — the cancer pathway is for older patients with uniform cells and risk factors, not a teenager with glomerular cells; D — the protein has already proved orthostatic, and one specimen alone does not justify empiric treatment; a subsequently confirmed collagen-IV diagnosis can change the RAS-blockade decision. Course reading: Evidence for this case
Part 3 — Course and Decisions
Answers for this section: Q5 · Q6 · Q7
Three weeks later Ethan and his mother, Laura, 44, come back to review two more fresh first-morning specimens, each collected after a rest day.
Q5Evidence update
Concordance-style practice: there is no expert panel behind this key, the teaching explanation. "Unchanged" means the finding does not move the hypothesis — not "I'm not sure."
If you were thinking "a benign orthostatic finding — reassure him and close the chart," and you then learn that both new specimens again show dysmorphic red cells (6–8 and 10–12 RBC/hpf, no protein), that Laura has "always had a little blood" in her urine, and that her brother went deaf at 30 and has been on dialysis for two years, this hypothesis becomes:
Much less likely
Less likely
Unchanged
More likely
Much more likely
Show answer and explanation · Link to this question
Correct answer: A
Learning point: The circumstances to notice are which side of the family the disease sits on and that Ethan is a boy. Glomerular hematuria on three samples, a mother with lifelong hematuria and her brother deaf at 30 and on dialysis is the X-linked pattern of type IV collagen disease: heterozygous women may have hematuria and can also develop proteinuria or CKD, while males with X-linked Alport syndrome have kidney involvement in essentially every case, and it progresses. The protein was orthostatic and stays benign, but "reassure and close the chart" is now much less likely; audiometry, an eye exam and genetics come next. Why not the others: B — also defensible with a clear explanation of the inherited-disease concern; C — the finding changes what you order, so it is not neutral; D and E — nothing here makes a benign course more likely. Course reading: Evidence for this case
Laura's own doctor had always called her hematuria "nothing." Ethan is booked for an audiogram, an eye exam and a nephrology and genetics visit.
The grandfather. At Thanksgiving, Ethan's paternal grandfather, Walt, 62, mentions that twice last week he passed bright-red urine with small clots, without pain. He has smoked a pack a day for 40 years and takes apixaban for atrial fibrillation. An urgent care gave him a five-day antibiotic course for a "UTI" and told him the blood thinner was the likely cause; the culture grew nothing. Hearing about Ethan, he wonders whether it is "the family thing." His primary care clinic sees him that week: a fresh urine shows 3+ blood, negative protein, leukocyte esterase and nitrite; microscopy shows more than 50 RBC/hpf, all uniform round discs, no casts and no white cells. Creatinine is 1.0 mg/dL (eGFR 85 by CKD-EPI 2021).
Q6The grandfather's turn
Walt, 62, has had two episodes of painless gross hematuria with clots. He has 40 pack-years of smoking, takes apixaban, and was treated for a "UTI" whose culture grew nothing. Today: more than 50 isomorphic RBC/hpf, no protein, no casts, creatinine 1.0. What is the right next step?
Hold apixaban for a month and repeat the urinalysis, since anticoagulants explain painless bleeding
Treat again for a urinary infection with a different antibiotic, then repeat the urinalysis in two weeks
Refer him to nephrology alongside his grandson, since the family's disease is in the glomerulus
Refer to urology for upper-tract imaging and cystoscopy; do not dismiss the bleeding because he takes apixaban
Show answer and explanation · Link to this question
Correct answer: D
Learning point: Read the cells before the family history: uniform red cells, no protein, no casts and clots strongly suggest a urologic source. Age, sex, smoking history and the degree of bleeding — here visible, with clots — are what the AUA/SUFU risk scheme weighs, and they send him for CT urography (upper tract) and cystoscopy (bladder). Anticoagulation can contribute to bleeding, but does not remove the need to investigate an underlying lesion, and a "UTI" with a negative culture was never proven — hematuria blamed on either must be shown to resolve. Why not the others: A — stopping apixaban risks a stroke and delays a cancer work-up; B — a second antibiotic for an infection that was never shown; C — Walt is on Ethan's father's side, and the family's collagen disease gives dysmorphic cells from childhood, not clots at 62. Course reading: Evidence for this case
Q7Another family, a different urine pattern
A father and daughter have slowly progressive CKD, little protein or blood in the urine, and a family history of early gout. Which inherited pattern should prompt nephrology and genetic evaluation?
Alport syndrome is proven by the absence of hematuria
Autosomal dominant tubulointerstitial kidney disease, particularly an UMOD-associated pattern
Post-streptococcal GN transmitted in an autosomal dominant pattern
Orthostatic proteinuria explains progressive kidney failure across generations
Show answer and explanation · Link to this question
Correct answer: B
Learning point: Autosomal dominant tubulointerstitial kidney disease can cause progressive CKD with a bland urine sediment. Early gout supports an UMOD-associated form but is not diagnostic. Recognize the family pattern and refer for appropriate genetic evaluation and counseling; a bland urinalysis does not exclude inherited kidney disease. Why not the others: A lacks Alport's usual hematuric pattern; C is not a Mendelian inheritance pattern; D does not explain progressive familial CKD. Course reading: Evidence for this case
Resolution and Teaching Points
Answers for this section: W1 · W2 · Q3 · Q4 · Q5 · Q6 · Q7
Ethan's audiogram showed a mild bilateral high-frequency sensorineural hearing loss he had never noticed; his eye exam was normal. Genetic testing found a pathogenic COL4A5 variant — X-linked Alport syndrome — and Laura carries the same variant. Nephrology discusses and initiates early renin–angiotensin-system blockade with monitoring, consistent with guidance for a male with confirmed X-linked Alport syndrome and microscopic hematuria, while following UACR, creatinine and BP; his 13-year-old sister has been screened with a urinalysis. Nothing in his urine kept him off the court, and he finished the season.
Walt's CT urography showed normal kidneys and ureters; cystoscopy found a bladder tumor, which the urologist removed. He is trying, again, to quit smoking.
Clinical Pearl — Two findings, one cup Separate the protein from the blood. A first-morning protein-to-creatinine ratio sorts transient and orthostatic proteinuria (usually benign; periodic follow-up) from persistent proteinuria. The blood is a separate question for the microscope.
Clinical Pearl — Hematuria is a microscope word Microscopy confirms red cells. Acanthocytes or RBC casts strongly support a glomerular source; their absence excludes little. Adult microhematuria guidelines and pediatric evaluation pathways are not interchangeable. After exercise, prove persistence on repeat specimens before you chase it.
Clinical Pearl — Route by the cells and the age Dysmorphic cells in a young patient with a family history go to nephrology and genetics, with audiometry and an eye exam. Uniform cells and clots in an older smoker go to urology for CT urography and cystoscopy.
Clinical Pearl — A pedigree is a test Persistent hematuria plus a male relative with deafness and kidney failure on the mother's side raises concern for X-linked Alport syndrome and prompts nephrology, genetics and hearing evaluation. Thin-basement-membrane patterns overlap with COL4A3/COL4A4 disorders; many patients do well, but proteinuria or CKD can develop. Avoid promising normal kidney function for life.
Clinical Pearl — From 13, the adult lines 120/80, 130/80 and 140/90 stage an adolescent's BP. Measure with a cuff that fits: an undersized cuff reads high.
Pitfall — The urology circuit for a teenager CT urography and cystoscopy for dysmorphic hematuria at 16 look in the wrong compartment, cost radiation, and miss the family's diagnosis.
Pitfall — Blaming the blood thinner Anticoagulation does not remove the need for an appropriate hematuria evaluation. Repeat microscopy after treating a proven UTI; painless gross hematuria in an older smoker still warrants urologic assessment.
Concept Links
Answers for this section: W1 · W2 · Q3 · Q4 · Q5 · Q6 · Q7
Assigned reading: the explanations in this case and the question-linked course evidence guide. The objective map distinguishes tested decisions from concepts taught in explanations.
Concepts: glom-01, glom-03, glom-05, glom-06, glom-26, htn-cardiorenal-17, structural-11.