Download When one wee is not enough

LabUpdate
March 2009
When one wee is not enough...
Dr Marek Havlat MBBS, BMedSci, FRPCA, FRCPath, FFPathRCPI, FASCP, FIAC.
Associate Professor Histopathologist and Cytopathologist St John of God Pathology and University of Notre Dame
The body invests much energy
generating variable volumes of highly
specialised fluid, urine, which then bathes
the entire urothelial mucosal surface of
the urinary tract prior to excretion.
Urine is easily examined to provide
information about disease:
• The chemical content can yield data
disclosing renal and metabolic
dysfunction.
• The microbial content can be
identified to diagnose urinary tract
infection.
• The cellular components assessed
microscopically for
* red cell morphology to determine
the likely source of haematuria.
** isomorphic cells = urinary
tract bleeding.
** dysmorphic cells = glomerular
bleeding.
* epithelial cell morphology to
diagnose and follow urothelial
neoplasia.
In addressing these three major
pathological parameters, attention to
detail with respect to urine collection is
extremely important.
Unfortunately, one urine specimen alone
cannot be used to investigate all three
parameters simultaneously.
Microbial Analysis
A mid stream urine sample should
be collected into a sterile yellow-top
container, at any time of the day.
• If chlamydial or gonorrhoeal
infection is suspected, a first void
•
•
urine sample is required. This must
be collected at least one hour after
the last micturition.
If urinary tract tuberculosis is
suspected, the first morning urine is
the best, as the bladder will
concentrate the sparse microbial
detritus overnight. The specimen is
collected in a sterile 500ml
container.
Cytological Analysis
Specimen collection
Cells do not survive long in urine and
rapidly undergo degenerative changes.
These degenerative cell changes hamper
pathological interpretation.
Therefore, the urine:
• Should be as fresh as possible
• Must be transported to the
laboratory without delay. Acceptable
delay from collection to processing
is <4 hours.
* For cytology, a post ambulatory
random voided urine without
prehydration is best.
* The early morning urine should be
discarded owing to advanced
degeneration of the exfoliated cell
content.
* While one fresh urine specimen
may help ascertain the source of
urinary tract bleeding, at least 3
specimens collected over a 2-week
period should aid in the detection
of most urothelial neoplasms.
Specimen preservation
If any delay is anticipated in the delivery
of a urinary specimen, methods for
specimen preservation should be
employed.
•
Simple refrigeration for up to
48 hours before processing
can be used without
significant loss of diagnostic
material.
•
Addition of alcohol can also
be performed.
•
Urine should never be frozen
or transported over dry ice.
Summary
The method of urine collection varies according to the clinical problem and one
urine specimen may not be enough to get
the right diagnosis.
Our Pathologists are available for
consultation any time about specimen
collection and result interpretation.
Call the Histology/Cytology Hotline
number for results & advice:
9213 2173
Dr Marek Havlat
St John of God Health Care is a leading provider of Catholic hospitals,
diagnostic and outreach services, basing its care on the values of
Hospitality, Compassion, Respect, Justice and Excellence.
Enquiries 1300 367 674
Domicilliary Bookings 9442 7691 Couriers 9442 7694