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99 Cards in this Set

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  • Back

What three pigments give urine its normal coloring?

Urochrome: lipid soluble pigment (yellow)

Uroerythrin: attaches to urates (pink)

Urobilin: oxidation product of urobilinogen (orange-brown)

If urine is dark yellow/amber/orange, you can shake it and look at the color of the foam to determine what is causing the abnormal color. Yellow foam=
White foam=

If urine is dark yellow/amber/orange, you can shake it and look at the color of the foam to determine what is causing the abnormal color. Yellow foam=

White foam=

Yellow Foam= Bilirubin

White Foam = protein

•Yellow-orangemany appear from large amounts of __________ being converted to ____________ (photo-oxidation)

•Yellow-orangemany appear from large amounts of __________ being converted to ____________ (photo-oxidation)

•Yellow-orangemany appear from large amounts of urobilinogen being converted to urobilin(photo-oxidation)

Which UTI drug causes dark yellow/amber/orange pee pee?

What test does this interfere with? What color foam will there be when shaken? What other test must you perform on

Pyridium (phenazopyridine)

Interferes w/ urine dipstick tests b/c of orange pigment

Yellow foam (can easily mistake forbilirubin)

Performan ictotest

Abrown color appears in urine due to the oxidation of what to what? (inacid urine)

Abrown color appears in urine due to the oxidation of what to what? (inacid urine)

brown color appears due to the oxidation of hemoglobin to methemoglobin (inacid urine)

Where does myoglobin come from?

breakdown of skeletal muscle

how can you tell the difference between red urine caused by hemoglobin versus myoglobin?

Look at the plasma..

Red plasma=hemolysis, hemoglobin is the cause

Normal plasma=myoglobin is causing the red pee

What is the appearance of red urine that is due to intact red cells?

Red CLOUDY urine

Red CLOUDY urine

what could cause a "PortWine Red" colored urine?

The oxidation of porphobilinogen to porphyrins

List three nonpathologicalcauses of red urine:


•Pigmented food (beets and blackberries)

•Medication (rifampin (antibacterial), phenothiazine)

what two substances can causes yellow urine to turn brown upon standing?

Melanin (Oxidation product of melanogen(colorless)•Produced(in excess) when a malignant melanoma is present)

Homogentisic acid (A metabolite of phenylalanine, Produced from an inborn error of metabolism, alkaptonuria)

what meds cause a brown/black urine?

•Levodopa (Parkinson’s)


•Metronidazole (antibacterial)

What causes the following colored urines:


What causes the following colored urines:




Blue green: Pseudomonas UTI, Meds: Methocarbamol(muscle relax), Amitriptyline (anti-depress), mints w/ chlorophyll, oxidation of IV drugs

Blue: intestinaltract infections (Tryptophan to indole to indican (ingut))

Purple: Klebsiella, Providencia sp

What causes urine to be..

Pale yellow with low Specific gravity?

Pale yellow with high Specific gravity?



pale yellow w/ low specificgravity-- polyuria, diabetes insipidus

pale yellow w/ high specific gravity-- diabetes mellitus

Greenish: bilirubin oxidized tobiliverdin

Black: homogentistic acid, melanin (melanogen)

Pyridium vs Bilirubin causes urine to be what color?



State the clarity of these urines, from L to R

State the clarity of these urines, from L to R

Slightly cloudy: few particulates, print easily seen
cloudy: manyparticulates, print blurred
turbid: can't see print thru


Slightly cloudy: few particulates, print easily seen

cloudy: many particulates, print blurred

turbid: can't see print thru

Flip for the long list of causes of NonpathologicalTurbidity...

•Turbidity may be produced from specimens allowed to stand (bacteria) or refrigerated (amorphous)

•Squamousepithelial cells•Mucus•Crystals(amorphous)• Semen• Fecalcontamination•Radiographiccontrast media•Talcumpowder•Medications(creams, etc)

Most common cause of pathological cloudy urine

RBC, WBC and bacteria

RBC, WBC and bacteria

Define specific gravity (SG)..

what influences the SG of urine?

Ameasure of the density of the dissolved chemicals in a urine specimen (Densityof a solution compared with the density of water at the same volume andtemperature)

Influenced by the number of particles present and the size of the particlespresent

What instrument measures specific gravity using a prism to direct a monochromatic wavelength of light against a calibrated SG scale?

Refractometer. •Moreconcentrated = increased angle that light hits the scale

Refractometer. •Moreconcentrated = increased angle that light hits the scale

What specific gravity instrument must be correct for temperature and is based on buoyancy?



•Reagent strips measure only ionic solutes, so what molecules are not measured?

Large organic molecules (glucose & urea) are not measured

-Radiographic contrast media & plasma expanders are not measured

Specificgravity of theplasma(ultrafiltrate) entering the glomerulusis:

If the urine is less than that it's called:

If it's higher:


–Hypostenuric urine:specific gravity < 1.010

–Hypersthenuric urine:specific gravity > 1.010

Under what specific gravity value would you question the integrity of the sample?


Ave random specimen SG: 1.015–1.025

Abnormallyhigh SG results > 1.035: possibly intravenous injection–Onetype is radiographic contrast media–highmolecular weight plasma expanders (dextran)....

Will the reagent strip method be affected by these substances?

NO, reagentstrip methods or osmometry willnot be affectedby these two substances.

If the urine is too concentrated, how do you go about testing the SG?

Dilute 1:2

Multiply the last 2 digits of the measured by 2

What causes an ammonia scent is urine?

How bout a mousy odor?

Ammonia: Dueto the breakdown of urea from bacteria

Mousy odor:  phenylkenonuria(PKU) Geneticdefect, build-up of phenylalanine in body

Ammonia: Dueto the breakdown of urea from bacteria

Mousy odor: phenylkenonuria(PKU) Geneticdefect, build-up of phenylalanine in body

Which organs arethe major regulators of acid-base balance in the body

Kidneys and lungs

The first morning urine is acidic or alkaline?

Acidic.. 5.0-6.0

After a meal, the urine will be more acidic or alkaline?

This effect is called:

Alkaline tide

pH of normal random urine


Anything over 9 means it was improperly stored so you don't use it

uricacid crystals = _______ urine

uricacid crystals = acidic urine

Causes of:

Acid urine-

Alkaline urine-

Acid urine:emphysema,diabetes mellitus, starvation, dehydration,diarrhea, infections (with acid producing bacteria such as E.coli),high protein diet, cranberryjuice, certain medications• Alkaline urine: hyperventilation, vomiting, renal tubularacidosis, urease producing bacterial infections suchas Proteus, vegetariandiet, old specimens

The reagent strip test procedure uses a double indicator system:

•Methylred = changes red to yellow to pH•pH4.0 - 6.0

•Bromthymol blue= changes yellow to blue at pH•pH6.0 - 9.0

Proteindetermination is the most indicative of what disease?

Normal urine contains a small amount of protein... how much?

Renal disease specifically early renal disease

Lessthan 10mg/dL or100mg/24 hr

Themain serum protein found in normal urine:

Albumin. Mostof the albumin in plasma is NOT filtered by the glomerulus•Mostof the filtered albumin is reabsorbed back to plasma

Whats the Tamm-Horsfallprotein?

It's producedby tubules, casts..

(major constituent of hyaline casts, believed to help fight microbial UTIs)

For the indication of protein on reagent strip test, what is the principle and what is the color change on the strip?

"Protein error of indicators" Proteins accept hydrogen ions from the indicator pad, causing a color change from yellow to green to blue.

"Protein error of indicators" Proteins accept hydrogen ions from the indicator pad, causing a color change from yellow to green to blue.

Why is the protein indicator on the reagent strip more sensitive to albumin than other proteins

Albumin has more amino groups and can accept more hydrogen ions.

How do you report out the protein level of urine

Report as:1+, 2+, 3+, 4+

... 30, 100, 300, 2000 mg/dL

What are the interferences for the protein error of indicator method>

Highlybuffered Alkalineurine

Overridesthe acid buffer system, producing a rise in pH ↑ = false positive

Sources of Error in protein testing on reagent strips

False pos:

False negs:

FalsePositives:•Highlypigmented urine•Contaminationof collection container with cleaning solutions (ammonia compounds)•Highspecific gravity•Bufferedalkaline urine

FalseNegatives: Proteins other than albumin

What are the three major categories of proteinuria?

Prerenal: conditions affecting the plasma prior to reaching the glomerulus. Not indicative of renal disease.

Renal: Can be either glomerular, tubular, orthostatic (postural). Renal disease=damage to glomerulus or tubules

Postrenal: protein is added totheurine as it passesthroughthelower urinary tract (ureters, bladder, urethra, prostate, vagina)

What are the typical conditions of pre-renal proteinuria?

(Usually an overflow develops because the protein concentration exceeds the RT)W

•Low MW plasma proteins•Hemoglobin,myoglobin, BenceJones

•Proteins associated with infections and inflammation responses

Whats a Bence Jones protein?

Whats a Bence Jones protein?

Aprotein excreted in multiple myeloma (Proliferativedisorder of plasma cells)

Consistsof monoclonal immunoglobinlight chains•Proteincoagulates between 40°C and 60°C•Itdissolves at 100°C (other proteins remain coagulated)•Multiplemyeloma diagnosed via SPE

Why will routinetesting with reagent strips will usually NOTdetect pre-renal proteinuria?

Because the reagent strips mainly measure albumin (False negative result)

How much protein will be in the urine when the glomerulus is damaged? how bout when the tubules are?

damage ~ 4g/day 

damage: produce low levels of protein

Glomerulardamage ~ 4g/day

Tubulardamage: produce low levels of protein

Causes of glomerular (RENAL) proteinuria?

material (Amyloidosis)  


complexes: lupus
and streptococcal glomerulonephritis

High BP

Amyloidmaterial (Amyloidosis)


Immunecomplexes: lupusand streptococcal glomerulonephritis

High BP

What substance in the urine indicatespre-eclampticstate?

Protein.. glomerular (renal) proteinuria

Protein.. glomerular (renal) proteinuria

Tubular (renal) proteinuria is due to: ...


Dueto inability of tubules to reabsorb albumin& LMW proteins

Toxicsubstances (Ethyleneglycol, antifungal agents, aminoglycoside antibiotics, radiographic dye) Hemoglobin& myoglobin•Heavymetals•Severeviral infections•Fanconisyndrome (Inheriteddisease affects proximal tubule)

What is FunctionalProteinuria?

Having protein in the urine with no pathology

Benign causes:strenuous exercise, high fever,dehydration and exposure to cold.

What is orthostatic proteinuria?

Due to increased pressure on the renal vein

(associated with young adults) 

position = ↑ protein  

Due to increased pressure on the renal vein

Benign(associated with young adults)

Verticalposition = ↑ protein


Causes of POST-renal proteinuria:

Bacterial & fungal infections and inflammations produce exudates containing protein from interstitial fluid

Blood, spermatozoa, prostatic fluid in urine can be a source of protein

What are two additional tests for protein?

1. SulfosalicylicAcid (SSA) Precipitation test (not as common). Cold precipitation test on centrifuged specimen

2. Microalbumin: Immunochemical (micral-test, Immuno dip) and dye-binding assays

What are sources of false negative in the SSA test?

Any substance precipitated by acid = false turbidity

Radiographicdyes (IDby looking at high SG)

Diabetesmellitus med (tolbutamide)

Antimicrobials– penicillin, sulfonamides

Microalbuminuriareagent strip test principle:

Albumin normal range:

microalbumin range:

clinical albuminuria:

Albuminbinds to dye, dye is specific/sensitive to albumin. Canmeasure 20-200mg/L (standard strips only measure >300mg/L)

albumin normal range: <20mg/L

microalbuminuria: 20-200 mg/L

clinical albuminuria: >200 mg/L

Albumin: Creatinine ratio



Clinical albuminuria:

A:Cnormal = <30mg A : 1 g C

Microalbuminuria= 30-300mg A : 1 g C

Clinicalalbuminuria: >300mg A : 1 g C

Why does microalbuminuria testing measure both albumin AND creatinine?

creatinine has a relatively stable output albumin can be compared to it

What is the renal threshold for glucose?

•Renal Threshold for glucose is 160-180 mg/dL

Which urine specimens give the best results for glucose testing?

Best results are obtained after a controlled intake of glucose and/or a fasting specimen

Reasons for glycosuria not of diabetic origin?

After a meal, hormonal function (Breakdownof glycogen to glucose: glycogenolysis(opposite of insulin), Pancreatitis,pancreatic cancer, acromegaly, cushing syndrome, hyperthyroidism•Increasesin: glucagon, epinephrine, cortisol, thyroxine•Resultin increased levels of circulating glucose) Renal glycosuria (glucose in the absence of hyperglycemia, tubules can't reabsorb glucose), Gestational diabetes,

What is the principle of glucoseoxidase method of reagent strip testing for glucose (2 step)?

step 1 – glucose oxidase catalyzes a reaction between glucose and air to produce gluconic acid and hydrogen peroxide.

step 2 – peroxidase catalyzes the reaction between hydrogen peroxide and a chromogen to form an oxidized colored compound.

What is the sensitivity of the glucose oxidase test?

Sources of false positives/negatives:

Sensitivity ~100 mg/dL

False positive: contamination w/peroxide or strong oxidizing substances (detergents)

False negative: contains enzymatic rxn or reducing substance interference (ascorbic acid); high specific gravity, low temperature; bacteria (2hr rule)

Glucose - Copper reduction test (Clinitest) principle:

Glucose - Copper reduction test (Clinitest) principle:

Glucose and other reducing agents reduce copper sulfate to cuprous oxide in the presence of alkaline conditions and heat

A color change occurs from a negative blue (CuSO4), through green, yellow, and orange/red (CU2O)

Which glucose test is not specific for glucose

Clinitest measures reducing substances and is not specific for glucose (glucose oxidase is specific for glucose).

Sensitivity for glucose ~ 200-250 mg/dL– (glucose oxidase method is around 100 mg/dL).

The Clinitest detects which sugar(s)?






and glucose, duh

Why is the Clinitest performed on ALL urine samples from kids under 2 yr old?

In newborn (or young child) “galactosemia

-Major problem is the lack of galactose-1-phosphate uridyl transferase (an enzyme). The lack of this enzyme prevents the breakdown of ingested galactose into glucose– resulting in failure to thrive

Name the three ketone bodies appearing in urineand identify which one is measured by the ketone reagent strip test

1. Acetone- 2%

2. Acetoacetic Acid- 20%

3. Beta-hydroxybutyric Acid (BHBA) – 78%

** Acetoacetic acid beaks down intoacetone and BHBA

Acetoacetic Acid- 20% is the one measured by the reagent strip method - sodium nitroprusside (nitroferricyanide)

Why monitor ketones?

DiabetesMellitus (type 1)•Indicatesdeficiency of insulin•Needto regulate dosage

Accumulationof ketones•Electrolyteimbalance, •Dehydrations•Acidosis-diabetic coma

What specimen can be used with the Acetest for ketones?

•This method can be used on serum (and other body fluids).

What is the clinical significance for blood in the urine

5 RBC/mL

Needto perform chemical test, Confirmwith microscope

List sources of false positives and false negatives in the reagent strip method for blood testing

False positives: Strong oxidizing detergents–Vegetable peroxidases–Bacterial peroxidases

False negatives: High levels of ascorbic acid (vitamin C)-Other substances such as formalin, an unmixed specimen, etc.


Major pathological causes:


Major pathological causes:•Renalcalculi•Glomerulardisease•Tumors•Trauma•Pyelonephritis•Toxicsubstances•Anticoagulanttherapy

Non-pathological causes:•Strenuousexercise•Menstruation•

If hemoglobinuria is due to the lysis of RBC in the urinary tract what will the urine be like?/

dilute and alkaline

whats hemosiderin

what stain makes it visible

denatured ferritin

Prussian blue

denatured ferritin

Prussian blue

what the heck does rhabdomyolysis mean?

muscledestruction that releases myoglobin in blood

Diagnosis of myoglobinuria

–based on patient’s history

–elevated serum levels of creatinine kinase and lactic dehydrogenase

Color of urine and plasma in:





-myoglobinuria = red/clear urine, clear plasma

-hemogloburia = red/clear urine, red/pink plasma

A precipitation test can be used to test for the presence of myoglobin in urine

Ammonium sulfate is added andurine is centrifuged. Where are myoglobin and hemoglobin found after centrifugation?

Hgb bindsto (NH4)2SO4, forminga heavy complex (at bottom of tube)

Myoglobin remains in supernatant

The appearance of bilirubin in the urine is indicative of what disease?

liver disease– liver damage, bile duct obstruction

Bilirubin is a degradation product of what?

Hgb (NOT due to RBC lysis)

How long do RBC live

120 d

120 d

Outline the steps in thedegradation of hemoglobin..

HGB broken down into PROTOPORPHYRIN (and other stuff) which is converted to unconjugated (indirect) BILIRUBIN (in the RES) which is insoluble in water so it is conjugated with glucuronic acid making DIRECT bili. DIRECT bili goes into liver then the bile duct and finally the intestine where it's reduced to UROBILINOGEN. In the feces, the urobillinogen (stercobilinogen) gets converted to UROBILIN makin' yo poop brown.

How do ya get conjugated bilirubin in the urine?

•Obstructionof bile duct

•Liverdamage (Cirrhosis•Hepatitis)

..Early indicator of liverdisease/obstruction

The Reagent strip test -Diazo reaction measures what?

What's the test principle?

BILIRUBIN. Bilirubin combines with a chemical in an acid environment to produce an azodye

Bilirubin Test (Diazo rxn)

False positives:

False negatives:

False positives:-Phenazopyridine, indican-urine pigments (medications, etc.)

False negatives:-exposure to light-Ascorbicacid

What confirmatory test is used when the bilirubin is positive on the reagent strip?

whats the sensitivity?


(0.05- 0.10 mg/dL)      


(0.05- 0.10 mg/dL)

The absence of urobilinogen in the urine (and feces) is clinically significant... why?

What does the feces look like when theres no urobilinogen?

It usually represents an obstruction of the bile duct (prevents bilirubin entering the intestine).

Palefeces because urobilinogen is colorless

Identify the reagent usedfor testing urobilinogen in the reagent strip test


Ehrlich’sreagent (P-dimethylaminobenzaldehyde). positive =red/pink color

MeasuresANY substance that react with, Testnot specific for urobilinogen

The presence of porphobilinogen in the urine is indicative of what?

Presence in urine = blockage in heme pathway

What test is used to differentiate btwn urobilinogen, porphoblinogen and Ehrlich-reactive compounds?




Which compound(s) is soluble in chloroform?

How about butanol?

Chloroform: UROBILINOGEN, in tube 1 the red layer will be on the bottom.

Butanol: UROBILINOGEN AND Ehrlich-reactive compounds. In tube 2, the red layer will be on top.

Porphobilinogen will not be extracted in either.

A rapid screening test for urinary porphobilinogen:

Hoesch Screening Test

Hoesch reagent: Ehrlich’s reagent dissolved in 6M HCl

In the Hosch Screening Test, what color will the tube be porphobilinogen is present?

How bout urobilinogen?

Red: porphobilinogen

Yellow: Urobilinogen (inhibited due to highly acidic pH)

Red: porphobilinogen

Yellow: Urobilinogen (inhibited due to highly acidic pH)

The nitrite test is based on the ability of certain bacteria to.....

Bacteria reduce nitrate (normally found in urine) to nitrite (not normally found in urine).

Nitrate test is used as a rapid screening test for the presence of urinary tract infections (UTI)

Cystitis is...

untreated cystitis can lead to..

bacterial bladder infection

pyelonephritis (inflammatory process of thekidney) can be a complication of untreated cystitis

Nitrite - False Negatives:

Nitrite - False Positives:

Nitrite - False Negatives: bacteria that don't have a nitrate reducing enzymes OR the bacteria further reduced nitrite into gas, antibiotics, Vit. C

Nitrite - False Positives: old sample (bacterial overgrowth), color interference

Leukocyte Esterase test detects what?

What is its biggest advantage?

This test detects the presence of esterase in the granulocytic WBCs (neutrophils, eosinophils, basophils, and monocytes)

Its biggest advantage is that it will detect lysed leukocytes (microscope will not detect lysed wbcs)

Leukocyte Esterase false pos and false negs?

False pos: Formalin or substances that act as dyes

False negs: High concentrations of protein, glucose, ascorbic acid (vitamin C)