Clinical Laboratory Diagnosis Lab – Spring 2007 – Quick Reference

Bilirubin

Jaundice

Urine
bilirubin / Urine urobilinogen / Fecal urobilinogen / Feces color / Ratio of unconj:conj
Hemolytic [pre-hepatic] / - /  increased /  increased / Normal / > 80 : < 20
mostly unconjugated / E.g. sickle cell leads to hemolysis, which increases bilirubin to liver, which can’t conjugate it all.
Hepatic / + /  decreased / Light brown / 50-80 : 20-50 / Pathway from liver to SI is impaired because of inflammation; sometimes bilirubin can’t be conjugated and goes to kidney
Obstructive [post-hepatic] / +
(goes to kidney instead of SI) / -
(never gets to SI) / - / White/clay / <50 : >50
mostly conjugated / Gallstones block common biliary duct. Liver is fine, but conj bilirubin can’t get out, goes to kidney into the urine.

Urine urobilinogen in hepatitis

Urine Urobilinogen
Mild hepatitis / Normal / System can handle amount of bilirubin being generated.
Very sick / Decreased / High degree of impairment. Looks like obstruction.
Very very sick / Increased / Urobilinogen goes from SI to liver for reabsorption but bypasses the liver to go to the kidney instead, because the liver can’t handle it.

Urine: Clean Catch

Urine can be contaminated by a non-steril container, hair, organisms from skin or clothing, bacteria from beneath the prepuce (males), or vaginal secretions (females) and bacteria from the urethra.

Supplies: three disinfectant/soapy towelettes (not alcohol wipes) and collection container (dry, clean, wide-mouthed, sterile if culture will be performed, at least 50-100 mL).

First morning urine is the most concentrated. Urinate for 1-2 seconds (20-30mL), then begin to collect urine.

Routine Urinalysis

Urinalysis should be performed within 1 hour of collection, or 8 hours if refrigerated.

  1. Macroscopic exam

aVolume – note approximate volume if routine, or exact volume if timed specimen (24h collection in diabetes, cortisol testing)

bColor – Normal colors include pale, straw, yellow. Amber may imply icteric urine (bilirubin), beets or porphyrin.

cClarity – Clear, cloudy, turbulent, etc

dDipstick

  1. Blot by tapping with side against paper, not by pressing paper against pads.
  2. If urobilinogen is positive, must follow up with Icto test
  1. Microscopic exam

aPour 10-15mL well-mixed urine into labeled conical tube. Cover tightly with paraffin. Centrifuge for 5 minutes at 1500-2000 rpm.

bRemove tube and decant all but 1 mL into sink. Mix sediment with remaining fluid.

cIf desired, add 1 drop of stain (Sedistain or Methylene blue).

dAdd 1 drop of mixed sediment to slide and cover with cover slip.

e10X: lower condenser, partially close iris (diaphragm)

  1. epithelial cells (average of 10 fields) – note type (squamous, renal, transitional)
  2. mucous from irritation, infection, crystals, ovulation
  3. casts (number and type per lower powered field) – usually congregate near edge of cover slip

f40X: raise condenser, partially close iris (diaphragm)

  1. cells (number per high powered field) – WBCs and RBCs
  2. organisms (occ, few, mod, many) – bacteria, yeast, trich, etc
  3. crystals (1+, 2+, 3+, 4+)
  4. amorphous sediment (1+, 2+, 3+, 4+) – note pH to determine type of amorphous sediment

Casts

Cast / Appearance / Disease
Hyaline / Homogenous, transparent, cylindrical structures with parallel sides and blunt, rounded ends, low refractive index, composed primarily of uromucoud or Tamm-Horsfall mucoprotein, often contains cellular or granular inclusions / Stasis – diminished rate of urine flow, urinary pH (acidic), degree of proteinuria, high solute concentration (may be physiologic)
Cellular: white cell / Semitransparent cylindrical structures filled with WBCs embedded in Tamm-Horsfall mucoprotein matrix / Inflammatory renal disease with exudation of WBCs into nephron
Cellular: red cell / Semitransparent cylindrical structures filled with RBCs embedded in Tamm-Horsfall mucoprotein matrix, may appear brown in color (hemoglobin pigmentation) / Diseases involving renal parenchymaglomerular basement membrane injury, always pathological, presence is very diagnostically significant
Cellular: renal tubular epithelial / Semitransparent cylindrical structures filled with renal tubular epithelial cells (single, large round or oval nucleus) embedded in Tamm-Horsfall mucoprotein matrix / Extensive sloughing of RTE cells following renal tubular damage
Granular / Cylindrical structures with coarse or fine particles or granules embedded in Tamm-Horsfall mucoprotein matrix, relatively high refractive index / Usually degeneration of cellular casts, granules can be derived from aggregated plasma proteins
Waxy / Structuers with homogenous, smooth glassy appearance, opaque with cracked or serrate dmargins and irregular broken-off ends, high refractive index, Tamm-Horsfall mucoprotein matrix / Advanced progressive degeneration of cellular/granular casts, imply localized nephron obstruction due to severe renal dysfunction
Fatty / Transparent cylinder filled with highly refractile lipid globules (oval fat bodies) or droplets in Tamm_horsfall mucoprotein matrix, cholesterol lipids are birefringent / Autolytic changes in cellular casts, composed of lipid-laden renal RTE cells

Correlation of diseases and microscopic findings in the urine sediment

Disease / WBC / RBC / Renal Epi Cell / Bact / Hyaline casts / Granular casts / WBC casts / RBC casts / Epi casts / Fatty casts / Waxy casts
Acute cystitis / 4+ / 2+ / 0 / 1+ / 0 / 0 / 0 / 0 / 0 / 0
Bladder cancer / 1-2+ / 2-3+ / 0 / /- / 0-1+ / 0 / 0 / 0 / 0 / 0 / 0
Strenuous exercise / 0-1+ / 0-1+ / 0 / 0 / 3-4+ / 1+ / 0 / 0 / 0 / 0 / 0
Lipoid nephrosis / 0 / 0 / 1+ / 0 / 1+ / 1+ / 0-1+ / 0-1+ / 0-1+ / 2+ / 0
Acute glomerulonephritis / 2+ / 4+ / 1+ / 0 / 2+ / 1-2+ / 1-2+ / 4+ / 1+ / 0-1+ / 1+
Acute pyelonephritis / 4+ / 2+ / 1-2+ / 2+ / 2+ / 4+ / 2+ / 0-1+ / 0-1+ / 0-1+
Nephrosclerosis hypertension / 1+ / 2+ / 1+ / 0 / 2+

Ictotest (confirmation of bilirubin)

Even trace amounts of bilirubin require further investigation. Always follow up with Ictotest.

Sample:random urine collection

Reagents: distille water, ictotest kit

Equipment:pipet, paper towel

Quality control:When Ictotest is required, Chek-stix control should also be run.

Procedure:Place square of absorbent test mat onto paper towel.
Place 10 drops of urine onto center of test mat.
Shake one Ictotest tablet into bottle cap and transfer tablet to center of moistened mat. Do not handle tablet with fingers.
Recap bottle promptly.
Place 1 drop of distilled water onto tablet.
Wait 5 seconds.
Place second drop of water so that water runs off tablet onto mat.
Observe color of mat around tablet after 60 seconds.

Results:Any appearance of blue or purple within 60 seconds is positive. Absence of fo blue or purple within 60 seconds is negative. Pink or orange should be ignored.

Urine Pregnancy Test

HCG concentration of 25 mIU/mL in urine can be observed within 7-10 days after conception. hCG can also come from hCG-secreting tumors on ovary or testes.

Sample:first morning urine. Run immediately, or refrigerate 2-8C for up to 48 hours and bring back to room temperature before running test.

Procedure:Add precisely 3 (or 4, depending on who you ask; check kit) drops to sample well (S).

Results:Read within 5 minutes. Lack of control stripe invalidates results.
Positive: C—
T—
Negative: C—
T
Invalid:C
T— (or whatever, doesn’t matter since there’s no control stripe)

Vaginal Wet Prep

Sample:Collect using sterile culturette or swab. Place swab in test tube with 1 mL of sterile saline.

Procedure:

Determine pH with litmus paper.

[sample] / [sample]
+ KOH / + saline
+ cover slip

Prepare slide:

Get a whiff of the KOH side for amine/fishy smell.

Microscopic exam of saline prep:

10Xlook for movement  Trichomonas

40Xcells, budding yeast, hyphae, clue cells, WBCs, etc

Results:

Normal: No organisms, no yeast, no trich, no clue cells.
Bacteria should be present.
No fishy odor.
pH < 5.0

Abnormal:report any of the following:
Indicate number and type of organisms.
Quantify number of WBCs.
Positive whiff test (fishy odor)
Variations in pH

Vaginitis: brief differential diagnosis (P Anderson)

Candidal / Trichomonal / B.V.
Etiology / Candida spp. / Trichomonas vaginalis / Gardnerella
M. hominis
pH / < 4.5 / Usually > 5.0 / Usually > 4.5
Amine (KOH) odor / None / May be present / Present
Microscopic / Hyphae
Yeast / Motile Tric. In 80% + of cases / Clue Cells!!

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Clinical Laboratory Diagnosis Lab – Spring 2007 – Quick Reference

Vaginitis: extensive differential diagnosis

Infection / Color of discharge / Odor of discharge / Consistency of discharge / Presenting complaints / Physical findings / Microscopic findings & pH / Relation of Sx to menses
Normal, no infection / Slate gray, white, clear / Normal body odor, no amine / Thin, homogenous, mucoid, tacky to stringy / None / None, no redness, swelling or itching. / pH 3.8-4.2. Squamous epis, lactobacilli, few WBCs / Increases around ovulation
Candidiasis / White/yellow, white/gray / None, yeasty or musty / Viscous, cheesy, thick plaques may be adherent to vaginal walls, creamy, thin, watery, curdy / Pruritis, burning, ext dysuria, dyspareinia, discharge or dryness, swollen vulva, recent ABX use, pregnancy / Vulvovaginal erythema, excoriations secondary to scratching, possible tissue friability / pH < 4.5. Pseudohyphae, yeast buds, increased WBCs, lactobacilli, KOH shows mycelia / Increased before menses, relief after menses
BV/Gardnerella / Gray/white / Fishy, amine / Thin, frothy or non-frothy, homogenous, milky / Odor, increased discharge, usually asymptomatic, burning, occasionally irritation / Absence of inflammation, pooling of d/c at introitis, positive whiff test / pH > 4.5 (5-6), pos KOH whiff test, clue cells, rare WBCs, normal to increased bact (rods) / N/A
Trichomoniasis / Yellow-green, yellow-gray, gray-green, yello / Foul / Foamy; thin and frothy; may be non-frothy; may be adherent / Pruritus, burning, dyspareinia, soreness, ext dusyria, new partner, multiple partners, UTI sx / Strawberry cervix/petechiae, erythema, cervical friability, occas. lower abd pain and inguinal lymphadenopathy / pH 5.2-7.0. Motile trichomonads w/ flagellae on wet prep in 60-70% of cases, many WBCs / Increased during and after menses
GC/Chlamydia / Green/yellow or purulent / N/A / None or mucopurulent / LA, PID, d/c, cervicitis, no sx, urethritis / + GenProbe; GC has > 10 WBC/HPF / pH 3.5-4.5 / None
Chem/allergic vaginitis / Normal / Normal / Normal / Pruritus, tender, burning, dyspar. / Erythema, edema, vesicles, oozing, ulceration, LA, thickened skin / pH < 4.5. Absence of pathogens. / N/A
Herpes simplex / White / Smelly / Thin / Prodrome, painful red vesicles / Vesicles, ulcers (genital, perianal, perineal) if outbreak / Nml wet prep; Ig multinuc cells on pap; culture fresh vesicles / Stress,menses may precip. outbreak

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Clinical Laboratory Diagnosis Lab – Spring 2007 – Quick Reference

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