Long-awaited answers!

....

Despite my despairing pleas, everyone didn't heed them and -still- posed tough questions for me! sigh.. and here goes,



Phui Yuen: hahaha yeah countless PBFs done, but there's still room for improvement! regarding your qns 'under what disease/clinical presentation is ESR done? or that ESR is just a general routine test done?', ESR isn't considered a general routine test but a miscellaneous(single) test ordered separately by the consultant himself/herself. ESR, as stated, is a nonspecific screening test whose results do not confirm a diagnosis of diseases. for eg, a patient can have a normal ESR readings and still have a problem. so yeah, basically it's up to the consultant to decide if he/she wants the test done to aid in diagnosis but that will be more towards clinical aspect.



Azhar: 'Since you said that the erythrocyte sedimentation process can be affected by a number of factors, is there any special equipment that is used to minimise these factors?'

hm actually there isn't any special equipment. perhaps the special and most important one is the ESR stand to support the tube in a vertical position for a more reliable and accurate reading. if you had noticed in the factors that i've stated, most of them would largely lean towards human variation(errors). also, the ESR stand is secured at the middle of the table and not near the ends where the alignment may not be equal and certainly not near any centrifuges.



Eugene & Nisha: hahaha. 'what's hairy cells?' they are cells with 'hairs'. ok lame :P the image is taken from a previous control slide but the presence of hairy cells in the blood basically shows that the patient is suffering from hairy cell leukemia(hcl), and hcl is classified under chronic lymphoid leukemia and a b-cell disease. the abnormal b-cell will have hairlike cytoplasmic projections on its surface. i dare not go into details for i'm not too sure myself!



Doreen: yeah my lab uses hematek2000 stainer but occasionally, manual staining using leishman stain. that's during time constraints. as for FBC report reflecting low platelet count, the follow-up actions will be to check for fibrin clot in the sample using wooden applicator sticks, any presence of giant platelets or platelet clumps in the blood film diagnosis which will be screened by the senior med techs and after which, they can proceed by doing manual differential count when necessary and report significant RBC and platelet findings.



Yeng Ting: to your first qns 'Rouleaux formation is the stacking of erythrocytes? Is the settling of erythrocytes equal to rouleaux formation?' yes, rouleaux formation is the stacking of RBCs atop one another. in ESR, the basic principle of the test is for the RBCs to form rouleaux and as the complex gets 'heavier', it generally settles down into what we call the packed cell volume. to your second qns 'In what ways can the ESR results be affected?' let me put this simply with a patient with sickle cell anemia as an example, sickle cells unlike normal RBCs are shaped like crescents. these sickle cells will still settle down but unable to form a typical rouleaux like normal RBCs probably with 'gaps' between them. so, going back to the principle of ESR, results will be affected by the structural variations of cells and in this case, give a decreased value.



Ying Ying: hahaha. i didn't see this coming. 'Why perpendicular and not vertical?' define perpendicular and it has the meaning of being vertical and upright in the sense that the 90-degree angle is created by the table surface and the ESR tube. so, simply put it this way, perpendicular in this case equals vertical!



Eunice: !!! 'Why are there 2 reference ranges for females?' the reference ranges listed were obtained locally based on results of healthy individuals. there being 2 ranges for females divided at about 50 years are probably due to normal physiology of females like menopause etc. there are significant changes of the mean result of females at <50>51 years during the tabulation of data and so the reference ranges were divided as so for females.



Lizzie: really? your place received over a thousand samples for ESR?! wow. hahaha.

ESR here are done manually. whether it is done before or after FBC totally depends on the amount of blood sample received. ideally, it would be done before FBC due to the waiting time of an hour but if there aren't enough blood in the sample to run both FBC and ESR, running FBC will be the priority.



Chaur Lee: yeah there certainly will be interference of results after 60 minutes as RBCs will still continue to settle down beyond the time frame resulting in false high readings. here, the count-down timer is a med tech's best friend. the reading is taken plus/minus 1 minute of the 60 minutes when the alarm sounds, so there is virtually a remote possibility that these results are not used. however, it's human to err so you wouldn't want to discount human errors if it happens? and yup, variations in RBC affect ESR results but in this case, ESR being a miscellaneous test is ordered by the consultant so maybe it's fair to say that we do our jobs by performing the test and report the results. :P



Wing Fat: 'What is platelet satellitism?' i must admit this is a new term to me when i saw the control slide and took a pic to share with you guys! how could you do this to me.. but yeah after some research(thanks ah), platelet satellitism is characterized by platelets forming around polymorphonuclear leucocytes(neutrophils) and are seen in blood films stained by Wright's stain prepared from EDTA-anticoagulated blood samples and not seen in other anticoagulants like sodium citrate, heparin etc. wouldn't go into details as this is only what i've learnt! thanks ah wing fat.



Jiaxin: hahaha. i suppose if the company is paying for your living, it is a must to learn to do everything. us as interns, if the supervisor deems you fit as to run patient samples, you are being treated like one of them and will be good to help around to your abilities and learn at the same time. so, the answer to your question is DO EVERYTHING!



Juexiu: for panic alarms such as excessively abnormal levels of platelets, haemoglobin and total white, we have to inform the wards immediately. while for general abnormal results from tests, we report the results and include comments with it.



Ci Liang: yeah, variations in RBC sizes affect the ESR results. i asked a senior med tech and she told me ESR for children were done mostly done in the western countries and it had been done here in the past, but not at present. but i've also found a reference range for children of 0-10mm/hr developed at Baptist Memorial Health Care Corporation, Memphis, Tennessee. hopefully it helps. :D



Peishan: this question got me thinking for quite a while, and i actually set up an experiment today just for you! it is definitely important to mix the ESR tube thoroughly before setting the test up to achieve a state of homogeneity between the components of blood. if blood is not mixed well, RBCs will settle at the bottom and form 2 clear distinct layers of plasma and RBCs. from what i've observed from my experiment, setting up the ESR test on blood that was not mixed(tube 1) will therefore allow the plasma region to be catapulted right to the top of the tube in place of homogenized blood from the control(normal ESR/tube 2). from the start, in tube 1, it can be observed that it isn't a fair test due to the segregation of plasma and RBC layer giving a reading of about 8mm following by the RBC layer that is unevenly spread while in tube 2, the reading is at the zero mark. after 60 minutes, the readings which i recorded were 85mm/hr and 32mm/hr in tubes 1 and 2 respectively. this clearly shows that the tube without mixing gives a false high result. after discussing on the findings with a senior med tech, it can be said that in the tube 1, some areas of the red cell layer had already settled down which MAY had formed rouleaux. with this uneven distribution of weight in the vertical ESR tube, say at the centre, it may force the RBCs further down along with gravitational pull which will give a high reading come the end of 60 minutes. these are of course, based on my observations and discussion, i really hope you did understand what i'm trying to bring. perhaps mr alvin poh[if he does read] can explain why?



Joan: both primary and secondary controls are commercial controls, given by the manufacturer of the automation. in the morning, the 3 levels of control (low/medium/high) is run in the machine before running patient samples to ensure that results fall within the manufacturer's given reference ranges. running secondary control also utilises the commercial controls but the difference is that only 1 of the 3 levels are used at the given time intervals. this is part of internal quality control and it also functions to keep patients' results in check within the reference ranges and that results are quality-assured.



Sharifah: hahaha in the lab, the ESR station is secluded in the middle of a single table. only materials involved in ESR are placed there, namely ESR stand, ESR tubes, timer, record book etc. the station is usually left alone after setting the ESR tests and no other materials known to cause vibrations are placed there. the only vibrations then, can only be due to people treating the table like a drum! but trust me, why play at the station? it's no fun! :P

AHHHHHHHHH! and trust me, answering questions are no fun! but of course, end of the day, i hope i did help in easing those lingering doubts that you once had and learnt something from my experience!

case closed! *wide grins :D* till my next post.. have fun everyone!