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Welcome to Ed's Pathology Notes, placed here originally for the convenience of medical students at my school. You need to check the accuracy of any information, from any source, against other credible sources. I cannot diagnose or treat over the web, I cannot comment on the health care you have already received, and these notes cannot substitute for your own doctor's care. I am good at helping people find resources and answers. If you need me, send me an E-mail at scalpel_blade@yahoo.com Your confidentiality is completely respected.

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Especially if you're looking for information on a disease with a name that you know, here are a couple of great places for you to go right now and use Medline, which will allow you to find every relevant current scientific publication. You owe it to yourself to learn to use this invaluable internet resource. Not only will you find some information immediately, but you'll have references to journal articles that you can obtain by interlibrary loan, plus the names of the world's foremost experts and their institutions.

Clinical Queries -- PubMed from the National Institutes of Health. Take your questions here first.
HealthWorld
Yahoo! Medline lists other sites that may work well for you

Alternative (complementary) medicine has made real progress since my generally-unfavorable 1983 review linked below. If you are interested in complementary medicine, then I would urge you to visit my new Alternative Medicine page. If you are looking for something on complementary medicine, please go first to the American Association of Naturopathic Physicians. And for your enjoyment... here are some of my old pathology exams for medical school undergraduates.

I cannot examine every claim that my correspondents share with me. Sometimes the independent thinkers prove to be correct, and paradigms shift as a result. You also know that extraordinary claims require extraordinary evidence. When a discovery proves to square with the observable world, scientists make reputations by confirming it, and corporations are soon making profits from it. When a decades-old claim by a "persecuted genius" finds no acceptance from mainstream science, it probably failed some basic experimental tests designed to eliminate self-deception. If you ask me about something like this, I will simply invite you to do some tests yourself, perhaps as a high-school science project. Who knows? Perhaps it'll be you who makes the next great discovery!

Our world is full of people who have found peace, fulfillment, and friendship by suspending their own reasoning and simply accepting a single authority that seems wise and good. I've learned that they leave the movements when, and only when, they discover they have been maliciously deceived. In the meantime, nothing that I can say or do will convince such people that I am a decent human being. I no longer answer my crank mail.

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This page was last updated February 6, 2006.

During the ten years my site has been online, it's proved to be one of the most popular of all internet sites for undergraduate physician and allied-health education. It is so well-known that I'm not worried about borrowers. I never refuse requests from colleagues for permission to adapt or duplicate it for their own courses... and many do. So, fellow-teachers, help yourselves. Don't sell it for a profit, don't use it for a bad purpose, and at some time in your course, mention me as author and KCUMB as my institution. Drop me a note about your successes. And special thanks to everyone who's helped and encouraged me, and especially the people at KCUMB for making it possible, and my teaching assistants over the years.

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QUIZBANK

Microscopy (all)

Urinalysis WebPath Tutorial

SPOT URINE COLLECTION

You will frequently order tests on random, timed, and 24-hour urine specimens.

Since the chemical urinalysis is so easy, you'll perform it frequently in your practice. Counting the labor and reagents, it's $0.65 per test.

The real, hidden expense of urinalysis comes from its sensitivity, because it may prompt further studies that in the vast majority of people do not lead to the discovery of treatable disease.

I'd recommend a chemical urinalysis on everybody who has any symptoms suggesting kidney ("Uh, I just don't feel well lately") or bladder disease, and anyone you don't know well or who's sick without an obvious cause (you don't want to miss RPGN, Doc... Br. Med. J. 301: 329, 1990).

Screening aims to find treatable disease without excessive risk or cost of workups for false-positives.

When there are no symptoms, it seems reasonable to do a chemical urinalysis on a kid before he/she enters school (Pediatrics 100: 919, 1997); more frequent checking of children just generates costs by forcing you to do more tests that almost never turn up anything important.

The fad for screening kids for (and giving long-term antibiotics for) asymptomatic bacteriuria seems to be over (thankfully). Whether all pregnant women (even those with normal urinalysis) should have routine urine cultures for asymptomatic bacteriuria remains under discussion (Am. J. Ob. Gyn. 182: 1076, 2000).

You are already familiar with the emphasis on obtaining midstream urine, especially for culture. See Appendix I for instructions (you can copy it for patients).

Acrobatic skill is required, especially for women. There has always been skepticism, and most recently, just getting a midstream clean-catch seems to give as good results as anything more elaborate (Arch. Int. Med. 160: 2537, 2000).

To collect urine from incontinent adults, try sealing on an ileostomy bag (see Lancet 2: 394, 1982).

Squamous epithelial cells in the urinary sediment indicate contamination from the genital tract, making interpretation a problem. (Sometimes the vagina must be packed, or a tampon used.)

Opinions vary regarding the best urine to "spot-check".

First morning-voided specimens are best for checking ability to concentrate urine, and for nitrite and protein.

Formed elements in the sediment may be more numerous in the first morning-voided specimen, but will be better preserved in subsequent specimens. (This is especially important if you are sending some urine for cancer cytology.)

It is better if urine sent for bacterial counts, etc., has not "incubated" so long in the bladder.

*Diabetics still sometimes check their urine for glucose after meals, or to validate their blood results. This isn't a bad idea (J. Fam. Pract. 34: 495, 1992).

Regardless of what sample you send, it must reach the lab within an hour or two to yield useful results.

Bacteria multiply at an astonishing rate, and will convert glucose to acids rapidly. (Urea splitters will produce a strongly alkaline urine.)

Formed elements will lyse within a few hours whether or not there is infection, especially if the urine is hypotonic.

*Preservative tablets are available if the urine must stand around for a while (i.e., when a group of people are being screened as for insurance). These release mercury (which is bad for the environment) and formaldehyde. Refrigeration can also keep the specimens fresh for a few hours.

TWENTY-FOUR HOUR URINE COLLECTION

Obtaining a complete 24-hour urine collection requires cooperation from all concerned. Instructions like the set in Appendix I can make all the difference.

The lab can check the total urine creatinine to estimate whether the specimen is really complete. This works pretty well.

Choice of preservative for such a collection depends entirely on what you are planning to measure.

No preservatives or refrigeration is necessary if you are only planning to assay for heavy metals or * estriol. (Ask about a lead-free glass container if you are going to measure urinary lead excretion.)

Refrigeration only is enough for amylase, hCG, total protein, Bence-Jones protein, electrolytes, most drugs of abuse.

Sodium carbonate (5 gm) and protection from light are required for all porphyrin studies.

* Hydrochloric acid (15 mL) is recommended for delta-amino levulinic acid, calcium, and phosphorus.

Glacial acetic acid (*15 mL) is recommended for most steroids and catecholamine metabolites.

* Boric acid (15 gm) is recommended for uric acid, creatinine, proteins (if mailed), amino acids, 5'-HIAA, and a few steroids (estradiol, cortisol).

* Defense attorneys will attribute alcohol in the urine to fermentation by yeast; you can rule this (silly) defense out by using fluoride (J. For. Sci. 38: 266, 1993).

Labs that test for drugs routinely comment if the specimen is not urine (i.e., doesn't contain enough creatinine) or has had chemicals added to give false-negative tests.

CHEMICAL URINALYSIS

Dipsticks:

Today, the color and odor (if any) of the urine are noted, and the urine chemistries are performed using a reagent strip, with pads that change color ("Multistix" or "Chemstrip").

These are easy to use. Be sure to swirl the urine before dipping the stick, keep your fingers off the pads, and don't leave the strip in too long or allow the dyes to run.

Store the sticks at room temperature, in their light-proof bottle, with the lid on tight and the desiccant in place. The first pad to be damaged by improper storage is the important ketone pad.

* The 1980's brought us first an office dipstick-reading machine (such technology!), then machines to do the microscopic urinalysis as well (yesterdays Yellow IRIS, today's Sysmex UF-50 and UF-100). The latter do a pretty good job and once the initial investment is made, they're faster then using your own eyeballs and microscope. However, if the sediment really matters (i.e., you are looking for red cell casts), there's still no substitute for a human examiner. See Am. J. Clin. Path. 112: 25, 1999; Am. J. Clin. Path. 115: 605, 2001.

Appearance

The familiar yellow color of concentrated urine is due to "urochrome".

"Amber" urine: conjugated bilirubin

Red urine: hemoglobin (blood, free), myoglobin, porphyria, drugs (phenolphthalein, deferoxamine, some phenothiazines), beets (some people's metabolism)

Smoky/brown urine: altered blood (* acid hematin), alkaptonuria (turns brown on standing), melanin (i.e., disseminated melanoma), * rhubarb (some people, alkaline urine), * cascara (some people)

Dark orange urine: drugs (pyridium, rifampin, others). Bright blue urine: drugs (methylene blue, others). Fluorescent yellow: Overpriced vitamins. Don't dipstick these urines, as the colors won't turn out right.

Foamy urine: proteinuria, conjugated bilirubin, pyridium

Turbid/cloudy urine: WBC's, urates, phosphates

Fat globules on the surface: fat embolization

Odor: Limited usefulness.

Ammonia: Urea-splitting organisms.

*Asparagus: Autosomal dominant, methanethiol (Experientia 43: 382, 1987, such science!)

Specific gravity

This may be "determined" using a hygrometer, refractometer, osmometer (best, but who has one?), or an electrolyte-sensitive pad on some "dipstick" reagent strips. (The strips really measures ionic strength, and is really a pretty good screen. Generally, a low or high specific gravity proves good tubular function.

Specific gravity closely approximates osmolality, which is what you're really concerned about. This works except with x-ray contrast media or very high concentrations of glucose, or in babies (J. Ped. 108: 613, 1986; J. Ped. Surg. 21: 580, 1986).

Hyposthenuria: specific gravity less than 1.007. Think of diabetes insipidus, fluid loading.

Isosthenuria: specific gravity fixed at 1.010. Think of renal tubular dysfunction.

Checking the specific gravity is a good way of proving to stone-formers that they aren't drinking enough water: J. Urol. 146: 1475, 1991.

pH

This is determined by the color change of an indicator on the reagent strip. It is of limited usefulness.

*Urine pH reflects metabolic adjustments, and checking urine pH can detect renal tubular acidosis, currently a popular diagnosis among clinicians.

Normally, urinary pH rises after a meal (alkaline tide) because the parietal cells of the stomach pump alkali into the bloodstream. Surgeons can even use this to see if the vagotomy worked.

Strongly alkaline urine usually indicates urea-splitting by Proteus (* occasionally Pseudomonas, others).

*Grunge in acid urine is uric acid crystals; grunge in alkaline urine is calcium phosphate crystals. (Big deal!)

Protein

This is measured using the protein error of indicators. Normal adults lose up to 150 mg/24 hr. Office workup of proteinuria: Am. J. Med. Sci. 320: 188, 2000.

Dipstick approximations:

negative... 0-50 mg/L
trace... 50-150 mg/L
1+... 150-300 mg/L
2+... 300-1000 mg/L
3+... 1-3 gm/L
4+... >3 gm/L

If you want to assume that your patient puts out 1 L of urine per day, these equate to the daily protein output. If you drink a lot of water, you may have nephrotic-range proteinuria but show only minimal proteinuria on dipstick. If it really matters (i.e., pre-eclampsia), do a 24-hour urine (if you can; Am. J. Ob. Gyn. 170: 137, 1994). Savvy pathologists and clinicians may prefer a protein/creatinine ratio, which make the 24-hour collection unnecessary.

Normal: <0.2 mg albumin / mg creatinine
Nephrotic range: >2.0 mg albumin / mg creatinine


False positives for protein are caused by highly alkaline or highly buffered urine. Remember hemoglobin and vaginal secretions as sources of protein.

Proteinuria is the single most sensitive indicator of most renal disease, though of course it is not specific.

Nephrotic syndrome (selective proteinuria is better than nonselective), nephritic syndrome, tubular disease ("tubular proteinuria", largely beta2m, will not exceed about 1.5 gm/day), urinary tract infections and tumors.

You can have proteinuria quantitated (ask for "24 hr. quantitative protein"), checked for "selectivity", etc.

In the current era of intensive screening for diabetic proteinuria in order to institute therapy to prevent diabetic glomerulopathy (i.e., ACE-inhibitor; good stuff Ann. Int. Med. 118: 577, 1993), even the "trace" reading on the pad on the dipstick isn't sensitive enough. You'll want to quantify by other techniques (Hosp. Pract. 28(3): 129, March 15, 1993; Arch. Path. Lab. Med. 115: 34, 1991).

Of course, lots of things beside kidney disease can cause proteinuria.

Postural proteinuria (orthostatic, etc.): 3-5% of healthy young adults pass excess protein during the day, not at night.

Functional proteinuria (albuminuria): occurs with fever, cold exposure, stress, pregnancy, eclampsia, CHF, shock, severe exercise (persists up to 3 days following. See JAMA 253: 236, 1985.) Immediate investigation of "trace proteinuria", especially during acute illness, is not worthwhile; however, it's a pretty good indicator that something's seriously wrong with the body (check the first AM sample: Br. Med. J. 304: 1196, 1992).

Bence Jones globulin: plasma cell myeloma, macroglobulinemia, lymphoma. Reagent strips may miss it. Ask for a urine protein electrophoresis.

Most of the people who you discover to have proteinuria will prove to have healthy kidneys and bladders. In addition to the many, many people with orthostatic proteinuria, normal gloms become a bit more permeable during febrile illness, after exercise, and so forth.
If you discover proteinuria, and the rest of the chemical UA is normal and the sediment is normal, a few repeats over the next few weeks on first-voided specimens is worthwhile; if these are normal, reassurance should be all that's required.

If proteinuria persists, then check for azotemia and quantitate the protein. If there's azotemia and/or more than 2 gm is lost daily, it's time for a nephrology workup.

Glucose

The reagent strip method uses glucose oxidase and is very sensitive and specific.

False negatives can result from megadose vitamin C. (Lots of people are on megadose vitamin C. See Clin. Chem. 38: 426, 1992).

False positives (trace to +1) can result from the dipstick jar being left uncapped for a few days (Am. J. Clin. Path. 96: 398, 1992). Since the test is based on oxidation, strong false-positives will result in the presence of hypochlorite bleach ("I collected the urine in my empty 'Clorox' bottle", etc.) Tetracycline can also give a false negative.

Ketones (acetoacetic acid and acetone; strips do not detect beta-hydroxybutyrate)

*The reagent strip uses the nitroprusside reaction.

These reagents are especially vulnerable to improper storage (heat, uncapped bottle).

False positives result from L-DOPA metabolites (Rx for Parkinson's disease), * phthalein dyes (BSP, Ex-lax), and people with cystinuria (stones, remember?).

Many fasting people have some ketones in the urine. Large amounts indicate diabetic ketoacidosis or aspirin poisoning, and detecting these makes the test worthwhile.

Blood

*The reagent strips detect peroxidase from blood, and are as sensitive as microscopy (Br. J. Urol. 58: 211, 1986).

Hematuria is "microscopic" if the urine isn't red but the urinary sediment contains more than about 5 red cells per high power field.

In people with microscopic hematuria who have otherwise-normal labs and no signs or symptoms, further workup is unlikely to yield any useful information.

A lot of these people will turn out to have thin-GBM non-disease.

* Some microscopic hematuria is attributed to hypercalciuria, i.e., the oxalate crystals injury the bladder mucosa.

Positives also result from hemoglobinuria (intravascular hemolysis), and myoglobinuria (crush injury, electrocution, rhabdomyolysis). * Hypochlorite bleaches (that "Clorox" bottle again) produce a false positive.

False negatives result from megadose vitamin C, leaving the lid off the dipstick jar for a few days (Am. J. Clin. Path. 96: 398, 1991) or * formaldehyde. Intact RBC's supposedly will not react, but this seldom or never causes problems.

Hematuria is an important sign of glomerulonephritis, stones, tumors, TB, SBE, coagulopathy, infection, vasculitis, schistosomiasis, leptospirosis, etc.

Checking the urine for blood is the way to screen older folks for bladder cancer, which is worthwhile; an unexplained finding of hematuria is usually worth pursuing (Br. Med. J. 299: 1010, 1989).

In the "three-glass" method of checking a man's random urine, blood mostly in the first glass indicates penile urethral bleeding, while blood mostly in the third glass indicates prostatic bleeding.

Nitrite

The presence of nitrite suggests bacterial action. The reagent strips detect nitrite by its reaction with an azo dye.

Just how to check people, especially children, for urinary tract infections is a subject of much discussion today.

Infection seems to be defined as:
• more than 10⁵ colony-forming units / mL of clean-catch voided urine
• more than 10⁴ colony-forming units / mL of catheter-obtained voided urine
• more than 10³ colony-forming units / mL of urine obtained by suprapubic aspiration

Especially in kids, routine urinalysis (nitrite, protein, leukocyte esterase) often misses urinary tract infection (J. Fam. Pract. 40: 45, 1995; Arch. Ped. Ad. Med. 155: 60, 2001; Clin. Ped. 39: 461, 2000; Pediatrics 103: 843, 1999; Postgrad. Med. 109: 171, 2001, the last one from the DO's in Michigan). The current recommendation is to tap or catheterize a febrile child who you suspect has a urinary tract infection, even if "urinalysis is normal" (Am. Fam. Phys. 62: 1815, 2000.)

Using a bag to collect urine from a not-yet-toilet-trained kid is so likely to produce a false-positive result that the further interventions required actually place the kid at unjustifiable danger (J. Ped. 137: 221, 2000).

Bilirubin

The reagent strips detect conjugated bilirubin (which is the only kind that will show up in the urine) * by a diazo reaction.

*False negatives result from delay in testing the urine (the bilirubin-glucuronic acid bond breaks) or certain drugs. But in this era of cheap chemical profiles, who needs a urinalysis to detect conjugated hyperbilirubinemia?

Urobilinogen (remember this is colorless)

*The reagent strips detect urobilinogen by the Ehrlich aldehyde reaction.

Urobilinogen is very labile in acid pH and light, and the reaction is not analytically specific. Increased levels are quite a good way to screen for hemolysis (but other tests for hemolysis are much more sensitive and specific), or hepatocyte dysfunction.

Contrary to widespread belief, this pad is worthless for detecting porphobilinogen (acute intermittent porphyria and others) or uroporphyrin (porphyria cutanea tarda).

Leukocyte alkaline esterase on some reagent strips detects polys. It's a pretty good way to pick up a urinary tract infection if you're disinclined to look for WBC's in the urinary sediment (shame on you).

The last decade, with its emphasis on pretending to do everything on the cheap, saw an effort to use dipstick results-only to diagnose and start treatment for urinary tract infections and even urethritis in men. Be VERY cautious, especially if the diagnosis is not obvious on history and physical exam.

Confirmatory tests (for semiquantitative results, or if your are dissatisfied with your reagent strips for some reason)

*Protein: sulfosalicylic acid test. (False-positives result from x-ray contrast media)

Glucose -- "Clinitest", a copper reduction test that detects all reducing sugars. (Good for screening for inborn errors of carbohydrate metabolism, and, since it's a fizzy test-tube test, it is preferred by old-timers who "don't believe in dipsticks").

*Bilirubin -- "Ictotest tablets" (slightly more sensitive, but who cares?)

Future surgeons! You can use dipsticks on peritoneal lavage fluid to decide whether to operate people who have been stabbed in the tummy. Check protein content and white count: Br. J. Surg. 78: 696, 1991.

MICROSCOPIC URINALYSIS (see Arch. Pathol. Lab. Med. 108: 399, 1984 is still good)

Shake the urine, pour some into a test tube, spin it down (* 2000 rpm), and resuspend the sediment in 1 mL of urine.

Look at the sediment at high power using phase microscopy, polarized light, or the * Sternheimer stain. Use the supernatant for Bence-Jones protein determination, electrophoresis, sugar chromatography, etc.

Obviously, urinary sediment exam is only semi-quantitative. I have never understood why some physicians want to know how many of this-or-that were present per mL, given that this varies hugely with how much water the patient had.

Cells

Red blood cells

These appear as 7 micron pale discs. Hypertonic urine crenates them, and hypotonic urine makes them swell. Normally there may be 1-2/hpf.

* In glomerular hematuria only, red cells are likely to show certain dysmorphic features (acanthocytes, blebbed donuts). This fascinating observation is of no clinical usefulness, because (1) you can't appreciate the changes except with a phase-contrast microscope, and (2) it does not yield information that cannot be obtained with a standard history, physical exam, and routine labs (J. Urol. 160: 1492, 1998).

Polymorphonuclear leukocytes

Granular spheres ("glitter cells"), 12 microns across. Think of infection, of course; there are many other causes though these are less common.

Ten or more WBC/mm³ of urine says urinary tract infection, especially when the history and physical exam are right (Med. Clin. N.A. 75: 313, 1991). However, culture is more sensitive and of course more specific.

Renal tubular cells

Cuboidal cells. Think of renal tubular disease (pyelonephritis, ATN).

Lipid-laden cells

Tubular cells plus absorbed lipids (cholesterol esters polarize as Maltese crosses -- triglycerides require fat stain). Think nephrotic syndrome, diabetic nephropathy.

Other cells

Transitional cells (if you are concerned about tumor, send urine for cytology), squamous cells (vaginal), sperms, trichomonads, "miscellaneous" (see Am. J. Clin. Path. 77: 1126, 1984).

Eosinophils are easy to see if you use Wright's stain or Hansel's stain (NEJM 315: 1516, 1986). More than 5% eosinophils suggests allergic acute interstitial nephritis or (nobody knows why) atheroembolization, though if you want to be sure, a renal biopsy is required.

Bacteria

Yes, you can easily see them. Again, current opinion seems to be turning against the practice of "treating" asymptomatic bacteriuria in children to prevent kidney damage: Am. J. Dis. Child. 146: 343, 1992.

Casts

The basic material is precipitated protein and matrix secretion (Tamm-Horsfall mucoprotein) from ascending loop of Henle and distal convoluted tubules. Casts are likely to form when there is slow flow of concentrated, acidic urine in the nephron.

All cellular casts undergo degeneration to granular and waxy casts

Hyaline casts: normal finding. Excess number is "cylinduria", no real significance.

*"Hyaline" casts with adherent epithelial cells and/or giant cells are probably composed of myeloma protein.

*A PAS stain may be useful if you suspect a deep fungal infection of the kidney.

WBC casts: acute pyelonephritis (much less often, lupus or other interstitial nephritis)

RBC casts: nephritic syndrome or necrotizing glomerulopathy

Granular casts (coarse or fine): look for some other casts

*Epithelial cell casts: think of tubulointerstitial disease

*Fatty casts (i.e., fat within tubular epithelium): think of the nephrotic syndrome -- but the diagnosis should be obvious already

*Blue fluorescent casts are triamterene (Nephron 51: 454, 1989). You are asking for triamterene nephropathy.

Waxy and broad casts: this is bad renal disease

Crystals



We think only calcium oxalate, cystine, and magnesium ammonium phosphate are worth knowing.

Acid urine:

calcium oxalate (octahedra, etc.): finding a few isn't abnormal, or think of vitamin C faddist, ileitis, ethylene glycol poisoning, or a spinach gourmet....

cystine (colorless hexagons): cystinuria (this one's important to know, because it indicates a treatable disease....)

*uric acid (brick dust, rhomboids, hexagons, squares): normal. If numerous, think of gout or leukemia (but you probably already know the patient was hyperuricemic....)

*leucine (bicycle wheels) and tyrosine (sheaves): severe liver disease (but you knew about that anyway....)

*sulfa drugs: a great variety of beautiful crystals may appear in the urine. Oooh! (The old sulfa preparations precipitated in the tubules and often caused severe damage.)

Alkaline urine:

magnesium ammonium phosphate ("triple phosphate", "struvite"; "coffin lids"): infection with urea splitting bacteria

*ammonium biurate ("thorn apples"): ditto

*calcium phosphate (amorphous dust): no real significance

* Indinavir produces crystals in patients being treated for HIV: Arch. Path. Lab. Med. 124: 246, 2000.

TO THINK ABOUT:

1. Why is it often so difficult to obtain a complete 24-hour urine specimen? When do you really need one?

2. Millions of Americans take big doses of vitamin C daily. How does this complicate the chemical urinalysis? Is this important?

3. Why is there no widely-accepted standardized procedure for microscopic urinalysis?

4. Recreational drug users often try to obtain opiates by feigning renal colic. What might an enterprising junkie do to make his or her presentation more convincing? How might the suspicious clinician detect the deception? Why might a malingerer spit in his or her urine specimen?

5. Which of the following are "worthless"? This was a big question in the 1980's, when gouging third-party payers for "routine tests" supported other services that were not fairly reimbursed. Ask your clinical teachers. Ask the third-party payers. Ask a lawyer.

a."Routine urinalysis" on:

• orthopedic admissions (worthless: Am. J. Med. 148: 1370, 1988);
• all hospital admissions (worthless: Am. J. Med. 82: 719, 1987; Med. J. Aust. 151: 151, 1989);
• routine physical exams and hospital admissions (worthwhile: Lancet 1: 747, 1988);
• outpatients (worthwhile: Br. Med. J. 297: 1173, 1988);
• folks at the shopping mall (worthwhile: Clin. Chem. 33: 2106, 1987).

b. The "bilirubin" pad on the dipstick

c. The "urobilinogen" pad on the dipstick

d. Urine sediment examination following a normal chemical urinalysis

• worthless: Am. J. Clin. Path. 86: 658, 1986; Am. J. Clin. Path. 87: 423, 1987; Clin. Chem. 33: 418, 1987; Lancet 1: 747, 1988; J. Clin. Path. 92: 78, 1989
• not worthless: Am. J. Clin. Path. 85: 590, 1986; Am. J. Clin. Path. 88: 498, 1988. Both weird.

e. Following up a "trace positive" urine protein with more tests

f. Urine culture in immunocompetent patients in the absence of WBC's

• worthless: Ann. Int. Med. 104: 212, 1986

g. Most of what you read about urine crystals

• worthless: ERF

h. Urine porphobilinogen on an improperly collected sample

• worse than worthless: ERF

i. Screening the pediatric population for asymptomatic bacteriuria

• controversial at best: J. Ped. 125: 6, 1994)

1. Retract foreskin (if not circumcised).

2. Using one of the towelettes provided, cleanse the urethral opening with a single stroke directed from the ring of the glans toward the tip. Discard towelette.

3. Repeat cleansing procedure using two more towelettes.

4. Void into the toilet and continue to void but interrupt the stream to collect urine into the supplied container.

5. Close the container, complete information on label, and attach it to the specimen container.

1. While seated on the toilet spread the outer folds (labia majora).

2. Using one of the towelettes provided (see step 2 above), wipe the inner side of one inner fold (labium minor) by using a single stroke from front to back; discard towelette.

3. Using a second towelette, repeat step 2 on the opposite side.

4. Using a third towelette, cleanse urethral (urinary) opening with a single front-to-back stroke.

5. Void into the toilet and continue to void, but interrupt stream to collect urine into the supplied container.

6. Close the container, complete information on the label, and attach it to the specimen container.

For proper evaluation of tests on a 24-hour urine sample it is important that a complete and accurate collection be made.

Drink less liquids during the collection period than you usually do, unless instructed otherwise by your physician. Do not drink any alcoholic beverages.

1. Empty your bladder when you get up in the morning and discard this urine.

        (______________ A.M., __________________________)
                  (time)                                    (date)

2. From then on collect in a clean bottle all urine you pass during the day and night.

3. Make your final collection when you empty your bladder the next morning at the same hour.

        (______________ A.M., __________________________)
                  (time)                                    (date)

4. Keep the collected urine refrigerated, if possible, and bring it to the office or laboratory as soon as possible after the 24-hour collection is complete.

Drop by and meet Ed

Ed says, "This world would be a sorry place if people like me who call ourselves Christians didn't try to act as good as other good people ." Prayer Request

Teaching Pathology

PathMax -- Shawn E. Cowper MD's pathology education links
Ed's Autopsy Page
Notes for Good Lecturers
Small Group Teaching
Socratic Teaching
Preventing "F"'s
Classroom Control
"I Hate Histology!"
Ed's Physiology Challenge
Pathology Identification Keys ("Kansas City Field Guide to Pathology")
Ed's Basic Science Trivia Quiz -- have a chuckle!
Rudolf Virchow on Pathology Education -- humor
Curriculum Position Paper -- humor
The Pathology Blues
Ed's Pathology Review for USMLE I
Part I
Part II