Hey. I am Siti Shahimah from TGO1 and I am posted in clinical chemistry lab. Firstly, I am going to talk about the urine phase contrast microscopy (UPCM). This technique helps to examine urinary constituents. These constituents are red blood cells (isomorphic and dysmorphic), white blood cells, casts, crystals, microorganism, and other (e.g. yeast cells and spermatozoa). The difference between iso/dysmorphic red cells are their appearance. Isomorphic red cells appear bright under microscope whereas dysmorphic appear dark and sometimes has a hole-like in the middle of the cell. In UPCM, Med-Fuchs Rosenthal Counting Chamber is used. This is different from the one that we used in school. This chamber consist of 9 big squares with 16 small squares in each big squares.
This is the summarised steps in performing UPCM.
1) Mix urine sample well.
2) Pour 10ml of urine sample into centrifuge tube.
3) Centrifuge the tube at 2000rpm for 10 minutes.
4) Discard supernatant.
5) Vortexed the remaining volume of urine.
6) Load the sample into Med-Fuchs Rosenthal Counting Chamber.
7) Examine under microscope (40x).
I have also performed urine and serum osmolality. In this lab, I used two osmometers and they are called Vapor Pressure osmometer. These osmometers are different from what we have in school. In school, we used the freezing point depression osmometer. Vapor Pressure osmometers help to measure osmolality by using thermocouple found in the chamber of osmometer. These osmometers are very sensitive and produce quite accurate results.There are two osmometers so that we can tally to see if the results are consistent with each other or not.
The difference in the osmometer results must not be more than 10 mOsm/kg. There was once when one of the osmometers result showed more than 10
mOsm/kg difference and the staff had to recalibrate both of the machines by using three different levels of standard. Level 1 is 290 mOsm/kg, level 2 is 1000 mOsm/kg and level 3 is the 100 mOsm/kg. After recalibration/ switch the machine off and do test for QC materials, the osmometer result is acceptable.
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Why the machince has to be switched off after calibration before performing the control? Is it necessary?
ReplyDeleteOther than the morphological differences of isomorphic and dysmorphic RBCs, what about their indications to the patient's condition?
ReplyDeleteEriko
Hi I'm Jia Hui (joey),
ReplyDeletea question to ask:
For Med-Fuchs Rosenthal Counting Chamber, is there any other additional differences between the haemocytometer that we used in school? Are the techniques used similar, such as there is the use of coverslips and are the principles similar to that of the haemocytometer used in school?
Jia Hui,
01st July 2009; 22:18PM
To Ms Chew,
ReplyDeleteIt is not necessary to switch off the machines before we perform the controls. This same goes to performing recalibration. Switching off the machines is just to cool down the machines as our lab run 24 hours. So, sometimes it is not necessary to switch off the machine for recalibration.
Siti
To Eriko,
ReplyDeleteUrine Phase Microscope mainly checks for isomorphic and dysmorphic red blood cells. Predominant isomorphic red cells indicate that the disease is due to non-glomerular source of bleeding (e.g. bladder, ureter) whereas predominant dysmorphic red cells indicate glomerular bleeding.
Siti
To Jia hui,
ReplyDeleteYes, there is a different between those two counting chambers.For Mod-Fuchs Rosenthal Counting Chamber, the central square has 16 small squares whereas the haemocytometer in our school ( Neubauer), the central square has 16 small squares and each square is subdivided into 25 smaller squares. In addition, the microscope used is different.Mod-Fuchs Rosenthal Counting Chamber utilizes Olympus BX40 microscope whereas Neubauer utilizes Olympus BH-2 microscope.The techniques and principles are the same as our school haemocytometer.
Siti
ps: By the way, it is no Med-Fuchs Rosenthal Counting Chamber, it is Mod-Fuchs Rosenthal Counting Chamber. The 'e' change to 'o'. Sorry:)
Siti!
ReplyDeleteI was attached to urinalysis section this week. However, i didn't get the chance to conduct UPCM.
Is there a diffrence in what you see under the microscope for UPCM compared to the usual urine microscopy? If so, what are the differences?
Liyana
0703827F
Hi Siti.
ReplyDeleteThanks, I understand the differences. Hope you have fun at work (:
Jia Hui (:
04th July 2009
1715PM
Hey Siti!
ReplyDeleteHakim here! I was wondering, if the results of the osmometer exceeds 10mOsm/kg and you have to recalibrate and do a QC test, do you have to repeat the tests for those samples that were put in the machine even before the osmometer read 10mOsm/kg?
Or is it just that the osmometer's reading would be inaccurate only after its measurements exceed 10mOsm/kg?
Thanks! Happy SIPing!
Hakim
0703555C
Hey Liyaannaa!!
ReplyDeleteBasically, for UPCM, we are mostly interested in distinguishing isomorphic and dysmorphic red blood cells in urine.These different type of red cells indicate different source of bleeding( see the my reply to eriko's qn). I think that there is not much difference between a normal urine microscope and phase contrast microscope. However, phase contrast microscope is useful as it enhances the detection of casts and mucus in urine as well as the red blood cells!
siti :)
Heelloo Hakim!!
ReplyDeleteNo, we don't have to repeat the samples before the osmometer reading is 10mOsm/kg. And yes, we only test the samples again when the osmometer reading exceeds the 10mOsm/kg difference as it is already out of the range.
Siti :)
Happy SIP-ing to you too!
Hi Siti, i would like to know how the different cause of bleeding (glomerular and non-glomerular) result in the appearance of the red cells ( bright or dark and sometimes hole-like)respectively. Thanks!
ReplyDeleteZi shuang :)
0703383J
hey zi shuang.
ReplyDeleteThe red blood cells sometimes appear bright or dark is due to the haemoglobin (Hb) content. Usually, isomorphic cells will have normal Hb content, thus result in bright appearance. On the other hand, dysmorphic cells have no or lesser Hb content as the Hb has degraded. in additon, dysmorphic cells are caused by osmotic change of the red cells membraneduring passage through distal tubules.
siti :)