Urine examination

Urine Examination

Presented by

Rubab Malik &

Laraib Ayesha

Defination of urine

• Urine (from Latin Urina, ae, f.) is a typically sterile liquid by-product of the body secreted by the kidneys through a process called urination and excreted through the urethra.

Possible pathogens

• BACTERIAGram positive Gram negative

Staphylococcus saprophyticus Escherichia coli

Hemolytic streptococci Pseudomonas aeruginosa

Klebsiella strains

Salmonella typhi

Salmonella paratyphi

Neisseria gonorrhoeae

Parasites

(a) wuchereria bancrofti

(b) schistosoma hematobium

(c) trichomonas viginalis

(d) enterobius vermicularis

COMMENSALS • Bladder and urinary tract are normally sterile.• Urethra and perineum has wide variety of

gram positive and negative organisms.

(a) (b)

(c) (d)

Collection of urine specimen

• The first voided morning urine (most concentrated) - qualitative

• Random urine (routine)• 24hrs sample- quantitative• Mid-stream clean catch (most suitable for

urine culture)• Post prandial sample.

ATTENTION• Need to be examined within 1 hour.

Collection and transport

• IN A HOSPITAL WITH MICROBIOLOGY LAB.• Give patient sterile,dry,wide necked leak proof container and request

10-20 ml specimen.(clean catch specimen)• Female patients• Cleanse the area around urethral opening with clean water,dry the

area and collect urine with labia held apart.• Male patients• Wash hands before collecting specimen

(middle of urine flow)• Label container with date & name.• Number of patient & time of collection.• As soon as possible, deliver specimen

with request form to laboratory.

Collection and transport• IN A HEALTH CENTRE FOR DISPATCH TO A

LABORATORY.• Give patient a sterile,dry,leak proof container with

instructions how to collect a clean catch MSU.(mid stream urine)

• Add measured amount of boric acid powder (0.1g/10ml of urine) to preserve a specimen.

• Label container and send urine

with request form to reach

microbiology laboratory within

48 hours.

Laboratory examination of urine

• Appearance of specimenAppearance Possible cause

Cloudy (urine has unpleasent smell and contains WBCs)

Bacterial urinary infection

Red &cloudy (due to red cells) Urinary schistosomiasisBacterial infection

Brown &cloudy (due to hemoglobin) Black water feverIntravascular hemolysis

Yellow brown or green brown(due to bilirubin)

Acute viral hepatitisObstructive jaundice

Yellow orange(due to urobillin)

HaemolysisHepatocellular jaundice

Milky white(due to chyle)

Bancroftian filariasis

Colour and turbidity in urine specimens

Microscopical examination of Urine

• WBCS(PUS CELLS)• Round,10-15 um in diameter.• Report• Few upto 10 wbcs/HPF• Moderate:11-40/HPF• Many:more than 40

WBCs/HPF.

• RBCS• Definite outline and no

granules.• Reported as

few,moderate,many in number /HPF (high power field)

Microscopical examination of Urine

• CASTS(a) A hyaline cast with a 'fluffy'

appearance due to the fibrillary

substructure of Tamm–Horsfall

glycoprotein .

(b) A hyaline–granular cast.

(c) A finely granular cast.

(d) A waxy cast

Microscopical examination of Urine

YEAST CELLS• Oval shape and some yeast• Show single budding• Yeast are reported as

few,moderate or many / HPF(higher power field)

CRYSTALS (a) Uric acid crystals (b)calcium oxalate crystals. (c) calcium phosphate (d) Triple phosphate crystals.

Biochemical test for urine

• Biochemical tests which are helpful in investigating UTI (Urinary tract infection )

include

• Protein• Nitrite • Leucocyte esterase• Dipstick method is mostly

used in chemistry labs.

CULTURE THE SPECIMEN: Culture is required when the urine contains

bacteria(as indicated by Gram smear),cells,casts,proteins and nitrite.

ESTIMATING THE BACTERIAL NUMBER:

• Normal specimens may be contain small amount of organisms(less than 10,000/ml of urine)

• In untreated acute infections the number of bacteria will be more than 100,000/ml.

METHODS OF ESTIMATING BACTERIAL NUMBERS

1:CALIBRATED LOOP METHOD

1. Using quarter plates of culture media

2. Inexpensive

3. Simple to perform

4. Provides individual colonies

2:FILTER PAPER METHOD

(SINGLE COLONY REPRESENT ONE ORGANISM)

CYSTINE LACTOSE ELECTROLYTE DEFICIENT

(CLED)

• Allows the growth of both gram negative and gram positive pathogens

• Electrolyte deficient to prevent swarming of Proteus species

• Bromothymol blue indicator• Lactose fermenting colonies

appears yellow

• Mix the urine by rotating the container• Using a sterile wire loop,inoculate a loopful

of urine on plate of CLED ager• Incubate at 35-37°C overnight

CULTURE IDENTIFICATION

• EXAMINE AND REPORT THE CULTURES:

(CLED agar culture)• look for colonies that could be:• Escherichia coli• Proteus species• Pseudomonas aeruginosa• Klebsiella strains• Staphylococcus aureus• Staphylococcus saprophyticus• Enterococcus faecalis

APPEARANCE OF URINARY PATHOGENS ON CLED AGAR

E.coli: yellow (lactose fermenting) opaque

Klebsiella species: large mucoid yellow

Proteus species: transluscent blue gray

Pseudomonas aeruginosa: green

Enterococcus faecalis: small yellow

Staphylococcus aureus: deep yellow(uniform colour)

Coagulase negative staphylococci: yellow to white

CONTAMINATION SHOWS MIXED GROWTH

REPORTING BACTERIAL NUMBERS

• Estimate the number of bacteria,i.e colony forming units(CFU) per ml of urine

• Report the bacterial count as: Less than 10,000 organisms/ml not significant

10,000-100,000/ml doubtful significant

More than 100,000/ml significant bacteriuria

INTERPRETATION OF BACTERIAL COUNTS

• Interpret culture count in relation to clinical conditions.

• 105 organisms/ml or more => urinary infections• 104 – 105 /ml => infection or contamination (repeat

specimen)• Less than 104 /ml => contamination

• UTIs with low counts in urinary obstruction.

ANTIMICROBIAL SUSCEPTIBILITY TESTING

• On urines with significant bacteriuria, particularly in recurring UTI (Urinary tract infection).

TESTING URINE FOR HCG(PREGNANCY TESTING)

• First morning specimen.• Based on detection of rapidly rising levels of

hCG in urine or serum.• Investigation of suspected ectopic pregnancy,

threatened abortion or trophoblastic tumor.• IC (immuno chromatographic) card and strip

tests are able to detect 50mlU/ml of hCG.