urinalysis 1.5

clean all spills with

10% bleach or approved disinfectant

reagent labeling requirements

• received date, opened date, expiration date

• parallel check the lot number

reagent QC requirements and storage

QC each shift, at least 1x per day

oldest reagent should be used first

how often does proficiency testing happen (external QC)

3x per year

refractometer QC

daily

do cleaning and documentation

semiannual correlation with dipstick specific gravity method

how often should instrument QC be?

every shift/day/week/month/year

when are specimens processed?

ASAP

QC Centrifuge

• check RPM and record 2x each year

• check timer 2x each year

QC room temp and humidity

measured daily

take corrective action if outside of acceptable range

QC refrigerator/freezer

record temps daily and in specified ranges

how long is reporting/documentation saved?

at least 2 yrs unless electronic

anisotropic definition

directional dependent

• light, wood, metal, etc.

birefringent definition (pos/neg)

ability to bend light

Positive: rotates plane of light clockwise

negative: rotates plane of light counterclockwise

how does a polarizing microscope compensator work?

allows differentiation of

Ca pyrophosphate (+)

monosodium urate (=)

how does polarized light work?

it vibrates in only 1 direction/plane. substances that aren’t optically active allow light to pass through unchanged.

type I, II, III water

purified, reagent grade, distilled

polarizing filter used for what

allows light vibrating in east-west direction perpendicular to light path to pass to specimen

analyzer filter which light vibirates

only N-S direction can pass through

2 different QC materials (=,+)

=: can’t use distilled water

+: good QC has minimum RBC, WBC, etc

CLIA standard for QC material

test QC 1x per day

with new lot of QC, what to do with it?

parallel test each, recording lot #, expiration date, DAT, etc

QC how stable for how long?

little stability, 3-5 days

where is QC stored?

brown bottle because of bilirubin

if there are 2 instruments/methods, they must be corrected how often?

1x every 6 months to make sure both analyzers give the same/similar results

collection technique for random void

24-32 oz water 2 hrs before, random “clean catch”

usually need daily collection for 3-5 days

may not be accurate

midstream clean catch technique and purpose

clean external genitals, void at first and then collect the middle of the pee

purpose: eliminate contamination

catheterized urine technique

inserted into urethra and in bladder, gather in sterile bag, may causei infection

suprapubic aspiration technique

collect directly from the bladder with needle + syringe for bacterial cultures

pediatric urine collection technique

“wee bag,” check every 15 min

timed collection technique

used for quantitative assays, usually 12 or 24 hr gap due to exercise, circadian rhythm, hormones, proteins, GFR

urine kept in fridge/ice

benefits of first morning urine specimen

Immediately after sleep, urine is collected for metabolic analysis

• optimal detection (nitrites, proteins)

• RBC/WBC/Casts stable in urine

• cytology studies: usually more epithelial cells

• cell components and casts due to high osmotic environemnt

timed urine 9 collection errors

1. improper timing

2. 2 first morning urine specimen

3. filled to the brim

4. discarded part of specimen

5. improper measurement

6. transcription error in volume

7. mixing up specimens

8. inadequate preservative

9. discarded all of urine

most common urine preservatives (when you don’t measure right away)

refrigeration 4-6°C

boric acid preservatives in urine tubes

***organic things in urine

Hyaline Cast (Tamm Horsfall), Creatinine, Urea

****inorganic things in urine

some ions? maybe some sodium

***components present in urine and blood

RBCs, albumin, creatinine, glucose, hemoglobin, myoglobin, protein?

yellow (colorless, straw, yellow, dark yellow, amber)

normal urine color

abnormal urine clarity

hazy, cloudy, turbid

should be well-mixed and uncentrifuged to view

yellow color of urine from

• urochrome

• urobillin

• uroerythrin

epithelial cells, mucus, and fecal material can ____ normal urine if not collected properly

Cloud

cloudy specimens may contain what?

• crystals, amorphous urates/phosphates

• phosphates and carbonates

• acidic urines (amorphous urates

• RBC, WBC, bacteria

• Fat- milky

• Sperm

• infection (bacteria/yeast/trichomonas)

what abnormal things can urine have?

glucose, protein, ketones, lysed cells

bacterial infection with WBC and [casts/no casts]

casts: upper UTI (kidney)

no casts: lower UTI (bladder/urethra)

normal urine smells like

faintly aromatic

ammoniacal odor of urine happens because

urea sits too long and breaks down ammonia

Pus, protein decay, bacteria

fruity urine smell

diabetes (ketones)

“mousy” urine smell

asparagus

foul urine smell

infection

bleach urine smell

FAKE specimen

what happens if you shake a urine specimen containing bilirubin or albumin protein?

bili: yellow foam forms, it dissipates when standing

albumin: white foam forms, not dissipating

cloudy red urine vs clear red urine

cloudy: Acidic urines - amorphous urates (uroerythrin on urates)

clear: blood in urine

what happens if phenazopyridine (AKA____) is in a specimen?

pyridium, azo dyes, azo gantrisin, axo, gantanol

turns a specimen orange, causing false positives

black/brown urine caused by

disease/drugs/diet

bilirubin, hematin, methemoglobin, melanin, homogentisic acid (tyrosine metabolite

amorphous phosphates vs urates

urates: pink precipitate, acidic

phosphates: white precipitate

***how to test amorphous phosphates and urates

test within 2 hrs, crystals precipitate out in the cold temps

osmolality determines what?

solutes present in water volume, shown as specific gravity/osmolality

osmolality gives more information

proper storage of reagent strips

once opened, expiration date changes

keep out of sun

write received and opened date on container, monitor contamination comparing colors

DON”T MIX STRIPS from different containers

no bleach

reagent strip technique

• horizontal position

• timing

• adequate light

• hold strip close to container chart

preventing reagent strip discrepancy

read at correct time, don’t touch test areas, do confirmatory tests

premature reagent strip deterioration caused by

protect against heat, light, moisture

reagent strip image

purpose of confirmation tests

they’re more sensitive than the dipstick test for whatever you’re trying to get more info from

specific gravity vs refractive index

SG: includes all the solutes, both ionic and nonionic

reagent strip: only measures SGionic

Refractive index: shows everything

how to calibrate a refractometer

use water to calibrate at 1.000

Refractometer correction Glucose

Corrected specific gravity = SG – (0.004)(glucose g/dL)

Refractometer correction Protein

Corrected SG = SG – (0.003) (protein g/dL)

osmolality formula

isothenuria urine specific gravity

1.010

you lost the ability to concentrate

what 3 things can cause wrong results for pH?

1. improper storage with bacterial growth

2. container contamination

3. improper technique

what can cause a false positive SG?

moderate protein and ketones

what can cause a false = SG?

buffered alkaline urine

non-ionizable substances (comparing to refractometer)

what can cause false + nitrites

in vitro conversion: bacterial contamination, bad storage, delayed testing

medication: phenazopyridine/azo dyes

what causes false + leukocyte esterase

• substances that color urine: nitrofurantoin, bilirubin, phenazopyridine

• vaginal contamination

• strong oxidizing agents

elevated glucose (>3 g/dL)

high specific gravity

oxalic acid

high albumin/protein (>500 mg/dL)

antibiotics: cephalexin, cephalothin, tetracycline, gentamicin

ascorbic acid

CAUSES what??

what causes false = leukocyte esterase

menstrual/hemorrhoidal contamination

strong oxidizing agents (sodium hypochlorite, H2O2)

soaps and detergents

microbial peroxidases

CAUSES what??

what causes false + blood

high SG

high glucose/protein

antibiotics

unmixed specimen

high nitrites

ascorbic acid

CAUSES what?

what causes false = blood

what causes false + protein

buffered/alkaline urine

phenazopyridine, bleach

what causes false = protein

non-albumin protein

what causes false + ketone

free sulfhydral group (amino acid cystine, mecaptoethane sulfonic acid used in cancers, N-acetyl-cysteine used for acetaminophen overdose)

high pigmented urine

ketone false =

improper handling of urine

heat, moisture, light

what can cause hypostenuria (low SG) readings?

<1.010

diabetes insipidus causes impaired antidiuretic hromone (ADH) function

can’t concentrate urine

high water intake

what can cause hyperstenuria (high SG) readings?

>1.010

adrenal gland insufficiency

hepatic disease

CHF

why measure urine pH?

to modify diet/manage disease

emphysema/respiratory disease

diabetes mellitus

starvation

dehydration

diarrhea

acid-producing bacteria

high protein diet

cranberry juice

medication (methionine)

CAUSES what?

acidic urine can reveal what?

hyperventilation

vomiting

renal tubular acidosis

urease-producing bacteria

vegetarian diet

old specimen

CAUSES what?

alkaline urine can cause

what’s alkaline tide?

after eating a meal, urine is more alkaline

pH urine strip reaction

Methyl red and bromthymol blue double-indicator system

Methyl red: pH 4.4-6.2. -red-> yellow

Bromthymol blue: pH 6-7.6 -yellow-> blue

what’s paradoxical aciduria?

metabolic alkalosis where the distal tubule secretes potassium in exchange for sodium

pH confirmatory test

pH meter if needed

SG reagent reaction

pKa of polyelectrode decreases proportionally to urine ionic concentration

SG confirmatory test

refractometer

nitrite reaction

Lower urinary tract infection

Fecal contamination from intestinal bacteria E. coli

G+ enteric pathogens causing UTI have this.

nitrite confirmatory test

urine culture

Leukocyte Esterase reaction

reacts with neutrophils responding to bacterial infections (Trichomonas, Chlamydia, yeast)

Esterases catalyze hydrolysis of derivatized pyrrole amino acid ester to liberate 3-hydroxy-5-phenyl pyrrole (5-member ring)

Pyrrole + diazonium salt= purple product

leukocyte esterase confirmatory test

Microscopic analysis of sediment

Gram stain

Urine culture

bilirubin reagent reaction

Diazonium salt coupling in the reagent pad with bilirubin in an acid medium

Forms azo dye azobilirubin

Light tan → beige/pink

(0.5 mg/dL)

protein reagent reaction

Tetrabromphenol blue changes to blue-green if a proten is present

Reagent pad has a buffer to keep pad at pH 3.0

protein confirmatory tests

Electrophoresis, IFX, nephelometry, turbidimetry, radial immunodiffusion

blood reagent reaction

Tetramethylbenzidine and a peroxide in the strip. Peroxide is reduced, and the chromogen is oxidized to test the heme pseudoperoxidase activity

Yellow -> green dots from RBC

blood confirmatory test

Correlate with macroscopic, plasma color

80% ammonium sulfate

- Hgb precipitates OUT, = for blood

- Myoglobin soluble, still + for blood