Reception

Hey everyone! It's my turn (Felicia) to update this blog! ;)

What I'm about to update is on the reception aspect of Haematology.
You may think that the reception does not really play an important role in the entire process of Haematology. In that case, THINK AGAIN!

The reception is one the sub-sections of the Haematology lab and it plays an important role in receiving and processing samples for all the sections in the laboratory. It also handles telephone enquiries from customers for test results. 2 clerks are stationed at the counter. Operating hours for the reception are from 8am to 6pm from Monday to Friday and 8am to 1pm on Saturday.

From 8am to 4pm, each request form received by the counter is clocked-in to initial sample's receiving date and time.

For samples that require the FBC, clerks or technologists manning the counter should check ;

1. That the particulars on the request form tally with the information appearing on the sample label.
2. That the volume of sample is correct and
3. that the tube used is correct.

Once everything is in order, a lab number in ascending order is assigned for FBC samples and written down clearing on the bottom of the left of request form and on the samples tube. The staff who labelled the tube would initial beside the number on the request form. For additional tests, markings are made on the cap of the sample tube so that the technologist is reminded of these tests.

1. O for ESR
2. R for reitculocytes (Retics)
3. MP for blood film malaria (MP)
4. T for HbH Thalassaemia Screening Stage 1

The request forms are logged into the computer using the number assigned. After logging in the request into the computer, the forms together with the samples are brought into the routine lab for processing.

So you see, the reception plays a crutial role in the initial stage of haematological processing! If any data is being logged incorrectly, it may lead to many confusions when being dispatched into the different departments for the required tests.


Felicia
0703345I

Hi all! Qingling here! I apologise for the late post yeah!

This entry will be on Urine Dipstix!

The urine samples are first collected from the reception by the Health Care Attendant.
Afterwhich, they will tally the name and IC number on the container against the request form. After it is done, he/she will assign a lab number, open up the bottle cap and place them on a tray. 2 rows of 5 bottles each. The request form will be placed under the tray. The med tech will check the request forms to ensure the test ordered is correct. Patients with renal failure or request forms from the Renal Dept has to be tested using the dipsticks. Remove one strip from the dipstick bottle and replace the cap. Completely immerse all the reagent areas of the strip in the urine and remove immediately. While removing it, run the edge of the entire length of the strip against the rim of the urine container to remove excess urine. Then, compare the results with the corresponding color charts on the bottle label.

The intended use of the urine dipstick test is to provide tests for glucose, bilirubin, ketone, specific gravity, blood, pH, protein, urobilinogen, nitrite and leukocytes in urine.

The tips of the dipstick are impregnated with chemicals which react with abnormal substances in the urine to produce coloured end products. In some of the tests, the depth of the color produced is related to the concentration of the abnormal substances in urine.

Results should be reported in this manner :

For pH, the glomerulur filtrate of blood plasma is usually acidified by renal tubules and collecting ducts from a pH of 7.4 to about 6.0 in the final urine. Both normal and abnormal range is from 5 to 9.

For specific gravity, it measures the urine density. Random urine may vary from 1.001 - 1.035. Normal adults' urine with normal diet and fluid intake will have SG of 1.016 - 1.3022. Urine pH above 1.035 is either contaminated or have high glucose level.

For protein, normal protein excretion does not usually exceed 150mg/24hours or 10mg/100mL in any single specimen. Normally, no protein is detectable in urine. Color matching greater than Trace indicates proteinuria.

For glucose, dipsticks employing the glucose oxidation reaction for screening are specific for glucose but can miss other reducing sugars such as galactose and fructose.

For ketones, it should be negative in normal urine specimens. Detectable level of ketone may occur in urine during physiological stress such as fasting, pregnancy and vigorous exercise. In ketoacidosis, starvation or with other abnormalities of carbohydrate or lipid metabolism, ketones may appear in large amount before serum ketone concentration are elevated.

For blood, the significance may vary among patients. Blood is often but not always found in urine of menstruating females. It is highly sensitive to haemoglobin and thus complements the microscopic examination.

For bilirubin, there should be no bilirubin detected in normal individual. Trace amount are sufficiently abnormal to require further investigations. Thus colours that are unlike the negative or positive colour may indicate that bilirubin-derived bile pigments are present in urine sample and may be masking the bilirubin reaction.

For urobilinogen, it will detect the urobilinogen in concentration as low as 3umol/L in urine. A result of 33umol/L represents the transition from normal to abnormal.

For nitrite, it should not be detected in normal individual. Proportion of positive nitrite tests in cases of significant infection depends on how long the urine specimens were retained in the bladder prior collection.

For leukocytes, normal urine usually have negative result. Positive results are clinically significant and may be found in random specimens from female due to contamination of specimen by vaginal discharge.

Here is what i've drawn in my own notebook. This are pictures of how cells look like under microscope! Its not very bright. Sorry!

Thats basically all! Feel free to ask if you have any doubts! :D

MTS assay

CellTiter 96® AQueous One Solution Cell Proliferation assay (MTS assay)
It is a colorimetric method for determining the number of viable cells in proliferation or cytotoxicity assays.

MTS tetrazolium compound i.e. (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) is bioreduced by cells intro a coloured formazan product, which is soluble in tissue culture medium – decreasing toxicity to cells seen with an insoluble product (MTT assay). This conversion is accomplished by NADPH or NADH produced by dehydrogenase enzymes in metabolically active cells
Phenazine methosulfate (PMS), an electron-coupling reagent, is combined with MTS reagent to form a stable solution due to PMS’s enhanced stability.
The quantitiy of formazan product is directly proportional to the number of viable cells in the culture as measured by the absorbance at 490nm.

For the MTS assay, 5 x 103 cells per well were cultured in 96-well plates and treated with cytotoxic compounds (What I am studying) for 48 and 72 hours respectively. After incubation for specified times at 37°C in a humidified incubator, 25µL of MTS reagent was added to each well and further incubated for 2-4 hours. Absorbance was measured at 490 nm on a micro plate reader.

Advantages
• Fast – Eliminates solubilization of formazan crystals before absorbance reading and MTS is more efficiently bioreduced compared to MTT
• Safe – Requires no volatile (easily evaporated at normal temperatures) solvent to solubilize formazan product

Li Yinliang Alex 0704894E
TG02 Group 8
6 September 2009

Histology - Microtomy

HELLOS.

been experiencing some problems with blogger.. can’t make my postings. but anyway, i’m back to histopathalogy routine lab.. after a month at cytology and a month at processing area of histo lab.. so far what have been shared by the others on histology is staining, processing/trimming, embedding.. i shall touch on microtomy then~ =)

Microtomy, otherwise also known as sectioning, is as we all know from HTECH, the sectioning of tissue blocks using a microtome. After tissues are processed and embedded into paraffin blocks, it is then sent to the microtomy section for sectioning. Each tissue section produced can range from 2-25 microns.

Tissue blocks are first shaved/rough-cut, before it is being sectioned for microscopic viewing. Rough-cutting/Shaving is done at 20 microns per rotation/slice, until the entire surface of the tissue has been exposed. With rough-cutting/shaving, dense and hard tissues which may cause nicks and blunts to the microtome blade can be easily identified, as well as sutures and staples. If tissues are dense and hard, it is will then be pre-treated with RDO (decalcifier) and sectioned last (after all the other tissue blocks have been sectioned), as they might still cause nicks and blunts to the blade. Sutures and staples will be removed if identified. Nicks and blunts on the blade will cause score lines and poor sectioning of the tissue block, which may affect the diagnosis when evaluated by the pathologists.

After blocks are being shaved, it is then placed in 10% fabric softener solution for 5 minutes, and washed in water before placing them on cryoplate for chilling. Chilling of blocks is actually to facilitate fast sectioning, and renders tissue blocks hard for thin sections (normally 3-4 microns) to be produced.

The microtomes are those rotary microtomes, whereby the rotary movement is converted into up and down movement for sectioning, and a forward movement to advance the block for continuous sectioning.

Tissue blocks which are chilled, will be clamped onto the microtome, whereby thickness of the sectioning will be set at 3-4 microns, and section into even thickness and long ribbon of sections. These tissue sections will then be transferred onto the illuminated floatation warm water bath (set at 48 degree Celsius +/- 4 degree Celsius). Tissue sections can also be placed into 1% alcohol floatation bath before transferring to the warm water bath, which serves as an alternative when folds on the tissues are difficult to get rid of. Alcohol have a low vapour pressure which will increase surface tension of the sections, thus aid in the spreading of the tissue sections, so that it can be transferred flat, monolayer onto the microscopic glass slides.

Transferring of the tissue sections onto microscopic glass slides is done by ‘fishing’, whereby the desired sections will be ‘fished’ out of the floatation bath using the glass slides, and subsequently labelled with technican’s (who sectioned the block) initial, accession number (of the specimen), batch number, and block number.

Slides will then be placed on the hot plate (with tissue section facing upwards) for 3 minutes to ensure that the sections will not float off during staining. After which, it will be sent for staining (either H&E by the autostainer, or special stains such as PAS, GMS etc.)

Common faults which may be encountered during sectioning:

1. Ribbons fail to form, which can be due to

• paraffin wax too hard
• blade too blunt
• tilt/angle of blade is too great.

2. Sections compresed, wrinkled or jammed, which can be due to

• Blade too blunt
• Tissue block is still warm
• tile of blade and block is too slight

3. Split ribbon or scratches (score lines) in ribbons, which can be due to

• nicks in the blade
• tilt/angle of blade is too great.
• tissue is too hard
• blade edge is blunt (dull/rounded)

4. Sections full of folds, which can be due to

• floatation bath is too cold/warm
• tissue block is still warm

           Automated Microtome which we use in the lab!

               Controller for the automated microtome (close up)

Cryoplate

Illuminated floatation water bath

Manual Microtome(similar to the one we have in sch!)

Pictures Credit to Lab, taken with permission.

Cheers,

Ang Yu Hui Jacelyn
0702632A