HOSPITAL
SELAYANG PATHOLOGY DEPARTMENT
Microbiology Unit
Microbiology unit is divided into
7 benches. All benches have different role and was manage by one medical lab
technologist. The benches are Urine stool and respiratory bench, pus, genital
and body fluid bench, blood and cerebrospinal fluid bench, sterility and
antimicrobial bench, immunology bench, virology bench and clinical bench. Most
of test that been run in this unit is done manually except in virology and
dengue bench where some of the test was carried out using machine.
CLINICAL SECTION
Clinical test that been run in
this section are:
- Urine full examination Miditron Junior
- Urine microscopic examination SYSMEX UF100
- Stool Occult Blood
- Stool full examination and microscopic examination
- Rapid malaria test
a) Urine Full Examination Miditron Junior
Purpose: This test is
an automatically fully automated urine cell analyzer which is used to do the full examination
Method:
- Press start on the Miditron Junior machine
- Beep’ sounds and the ‘prepare strip’ display on screen.
- Remove a test strip from its container.
- After 4 seconds, see the ‘dip strip display on screen. Briefly dip the test strip sample when the LED flashes green
- With dray if and drawing the edge of the strip along the top of container to remove excess urine.
- Insert strip to the insertion area
- Placing it to the right of the test strip alignment guide (broken line) on the strip receiving tray.
- Scan patient specimen barcode
- The strip will be transported to the measuring position after 20 second
- When measurement is finish, the result is automatically printed
- Enter result manually into hospital computer system
Result
Test strip
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test
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Value
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Specific gravity
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pH
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Leukocyte
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Nitrit(e)
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Protein
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Glucose
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Ketone
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Urobilinogen
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Bilirubin
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Blood/Hb
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Ca5-10
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Principle behind each test
Specific gravity
Indicate the concentration of
urine ion have a good correlation with refractometric method. In the presence
of cation, complex agent will babaskan proton and change bromotymol blue
indicator from greenish blue to yellow
Leukocyte
Show the presence if granulocyte
esterase. Esterase will separate Indoxyl ester from indoxyl that react with
adiazonium salt and formed violet dye
Nitrate
Is based on the Griess’s test and
it is specific. A positive result will indicate the presence of nitrit and not
directly the presence of bacteria producing nitrit. The presence of slight red
still show a significant presence of bacteria
pH
test strip consist of Methyl red
and bromothymol blue indicator. Combination of both indicator will give
different color from orange to green to blue in the range of pH 5 to 9. pH <
7 indicate that urine is acidic and pH > 7 indicate urine is alkaline. Fresh
urine usually has pH range between 4.5 to 8.5 but more frequently in range of 6
or 7. Alkaline urine may indicate urinary tract infection while acidic urine
may indicate diabetes, dehydration or starvation.
Protein
This test strip is very sensitive
to detect presence of albumin, quinine, quinidine, chloroquine, tobutamide and
high pH (pH9) will not disturbed the test result. Protein reaction with the
test strip will change the color of test strip from green to light green.
Positive results indicate proteinuria and it is not a specific sign of renal disease.
Test strip reagent is more sensitive to albumin and the negative result will
not show the dispresence of other protein such as Bence Jones protein.
Glucose
Based on the specific action of
glucose oxidase or peroxidase. The result is based on the change of color of
strip from yellow to green. Normally glucose is not present in urine. The
presence of glucose in urine may caused by high intake of glucose or decrease
reabsorption in renal. Glikosurea is the first indication of diabetes mellitus.
Apart from that, it also present in condition such as pressure, akromegaly,
Cushing syndrome, acute pancreatitis, thyrotoxicosis, and patient with low
glucose tolerate.
Keton
Based on the principe Oral
Legal’s test that is more sensitive to acetoacetic acid from acetone. Ketone
was found in urine in high metabolism of body fat condition. This condition can
be found iin diabetes, low carbohydrate intake in the starvation condition,
fever, diarrhea, and vomiting. Test strip will react to acetoacetic acid more compare
to acetone and no reaction to β-hydroxybutyrat.
Urobilinogen
Stable diazonium salt will react
with urobilinogen and change the azo dye to red. Urobilinogen usually present
in urine but the elevation of it may caused by liver pathology or the excessive
disruption or red blood cell as in hemolytic anemia. With the bilirubin test,
this test will differentiate jaundice diagnosis.
Bilirubin.
Based on the action of coupling
bilirubin and diazonium salt..The presence of bilirubin in urine indicate liver
disease, biliary disruption or acute hemolysis. It may presence in urine before
other other sign and symptom appear. With the urobilinogen test, this test will
differentiate jaundice diagnosis.
Blood
Hemoglobin and myoglobin will
catalyse the oxygen peroxide indicator in the tast paper. Different scale of
color was used for erythrocyte and hemoglobin.
Erythrocyte – green dots on the
test strip indicate presence of normal erythrocyte.
Hemoglobin – Equal green color on
test strip indicate the presence of myoglobin or lyse red blood cell. The presence
of blood in urine indicate serious renal disease or urinary tract infection.
b) Urine microscopic examination SYSMEX UF100
Purpose:
This test is automatically fully
automated urine cell analyzer which are used to do the full examination and
microscopic examination
Picture of SYSMEC UF100
Sysmex UF-100
The Sysmex UF100 is designed to
bring efficiency and quality to routine urine microscopic analysis. It combines
the superior technology of fluorescent flow cytometry with fully automated
urine sample analysis. Continuous sampling or batch processing are easily
accommodated by the rack-based autosamplers, streamlining sample processing in
high volume laboratories. Flourescent flow cytometry and cluster analysis
provide automatic classification and identification of ten types of formed
elements. Unattended operation and superior formed element identification and
enumeration bring new levels of efficiency and standardization to the clinical
laboratory.
c) Stool Occult Blood
Purpose: this test is an
immunochromatographic test for fecal occult blood
Principle:
Based on the immunological
detection of human HbAo in feces. Ab to human Hb is used in imunochromatographic
reaction. The methodology increase the specificity to human Hb, therefore there
is no requirement for dietary reaction. Conventional fecal occult blood test is
based on the guaiac test, which is the peroxidase like ability of Hb to oxidize
a chromogenic material in the presence of hydrogen peroxidase. This test is not
specific for human Hb and Hb form various dietary regiment will cause a
positive reaction.
In the using of ON-LIGHT the
fecal sample is first diluted with buffer to stabilize the Hb and then this
buffered is reacted with Ab on strip. In the presence of Hb, the blue line will
be formed on the strip
Methodology
- Set up sampling bottle, putting the green cap down.
- Remove the white cone nozzle
- Insert the strip into the sampling bottle from the dip side
- Read test result. Presence of blue line the lower and upper center of the strip at 5 minutes
Interpretation
- Positive: Presence of blue line at the lower and upper center of strip may be condensed positive
- Negative: Presence of blue line only at the upper center of strip is negative
- Equivocal: No blue line in both lower and upper center of the strip or at lower center of the strip should be considered equivocal. Such sample should be retest by changing test strip
d) Stool Full Examination And Microscopic Examination
Purpose:
To identify
- E. hystolitica (amoeba)
- Giardia intestinalis, Entamoeba hystolitica cyst and Cryptosporidium
- Egg parasite under possible pathogen list
Method:
There are 2 ways of
determination:
Macroscopically
- Presence of blood or mucus
- Round worm, thread worm or tapeworm proglotid
- Color and smell of stool
Microscopically
e) Rapid malaria test
Purpose: Detection of an
infection by Plasmodium species in blood sample indicating
- The presence or absence of Plasmodium species
- Differential diagnosis of plasmodium sp.
- + Plasmodium falciparum (responsible agent for fetal causes of malaria)
- + Plasmodium vivax, Plasmodium malariae, Plasmodium ovale
Method:
- Take dipstick and label patient ID
- Place 1 conjugate well and 1 wash well in holder
- Dispense one drop (approximately 20µl) buffer into conjugate well and 4 drop (approximately 80µl) into wash well. Allow to stand for one minute.
- Put blood sample into conjugate well using pipette (approximately 10µl)
- Mix gentelly using applicator or the end of the pipette. Allow to stand for one minute.
- Place dip stick vertically into conjugate well and leave it in well for 10 minutes.
- Transfer into wash well and leave for 10 to 15 minutes
- Remove from well and read the reaction
Interpretation
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f) Urine Pregnancy Test
Purpose: Rapid chromatographic
immunoassay for the qualitative detection of human chorionic gonadotropin in
urine to aid in the early detection of pregnancy
Principle
Urine pregnancy test are designed
to detect the presence of Human Chorionic Gonadotropin (HCG) in urine. It is detectable
in urine of a pregnant women 26-36 days after the first day of last menstrual
period or 8-10 days after conception. The reagent strip test can be used to
detect the presence of HCG’ which signifies pregnancy. A negative test result
indicates the absence of HCG which signifies either a nonpregnant condition or
a clinically undetectable level of HCG because the test was done too early in
pregnancy
Procedure
- Specimen received from Central Specimen Receiving(CSR) unit
- Specimen was log in the system
- Allow the test strip, control to reach room temperature (15 minutes prior to testing)
- Bring the pouch to room temperature before opening it. Remove the strip from the sealed pouch and use it as son as possible
- With arrow pointing towards the urine specimen, immerse the test urine strip vertically in the urine specimen for at least 10 to 15 seconds.
- Place the test strip on a non-absorbable flat surface and wait for red line to appear.
- The result should be read at 3 minute
- Enter the result in computer system
Interpretation
- Positive result: Two distinct red lines appear. One line should be in control region and the other line should be in test line region
- Negative result: One red line appear in he control region
- Invalid result: Control line fails to appear. Such sample should be retest by changing test strip
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