Coagulation

Hey everyone. With only a few weeks down to the end of SIP, I bet everyone's been working hard on their MP. Anyway, for my turn in blogging, I'll touch on what I've learnt in the Coagulation section of the lab, which deals with blood samples that have been placed in 3.2% sodium citrate tubes. (shown above)

In this entry I'll highlight a particular test that is the most highly requested test for my section.
And that would be the test for Prothrombin Time (PT).

Prothrombin time is a test used to evaluate the extrinsic coagulation of the system. It can screen for congenital deficiencies of factors II, V, VII and X. PT can also monitor anticoagulant therapy (eg. warfarin medication), which is usually given on a long-term basis to patients who suffer from recurrent inappropriate blood clotting. The measurement of PT can aid in the control of the dosage of the drugs. PT is normally measured in seconds and the INR (Intl Normalized Ratio)

INR = (patient's results / normal patient average)

The ref range for patients on warfarin should be between 2.0-3.0. Those with high risk of clotting have a ref range of 2.5-3.5.

PT is usually evaluated with the results of Activated Partial Thromboplastin Time (aPTT) to assess the coagulation system better.

To run the test, my lab uses the Sysmex Ca-1500. We first check the tubes for clot then spin the sodium citrate tubes at 6000rpm for 3minutes. We then load the samples into racks and place them on the machine.The caps need not be removed as the machine has a probe that can pierce through the cap.

It works by using the Coagulation Reaction Detection Method (Scattered Light Detection Method)
It irradiates red light at 660nm onto a mixture of blood plasma with added reagent (Dade Innovin) and it will read a change in turbidity as the fibrin clots are formed. This measures the coagulation time.

It also uses the Coagulation Point Detection Method (Percentage Detection Method) to calculate the coagulation time. This is considered as the time taken to achieve the amount of scattered light that is set for the coagulation detection point, susing the amount of scattered light that is present just after the start of detection as 0% and the amount of light scattered that is present at the completion of coagulation as 100%.

Antibiotics, aspirin, and cimetidine can increase the PT/INR. Barbiturates, oral contraceptives and hormone-replacement therapy (HRT), and vitamin K - either in a multivitamin or liquid nutrition supplement - can decrease PT. Certain foods (such as beef, green tea, broccoli, chickpeas, kale, turnip greens, and soybean products) contain large amounts of vitamin K and can alter PT results.

Albumin

Hey everyone. I've been attached to the Biochemistry section of the lab for the about 2 weeks. And it's one of the busiest sections here in the lab as many tests are done in this section. Examples would be Glucose test, Liver Function tests, etc.

Here in the lab where I work in we use the Beckman Coulter Synchron LX 20. It is a fantastic analyser that can run multiple tests at any one time in closed tube samples.

Retrieved 16 August 2008 from http://www.beckmancoulter.com/products/instrument/genchem/images/LX20_PRO.jpg

Of all the tests that is done in the Biochemistry section, I'm gonna highlight the Albumin test, which is one of the tests in the liver panel. In acute hyperalbuminaemia, there will be a low oncotic pressure and this will cause the blood capillaries to be permeable to water. Hence, this will result in edema.

What is albumin?

Retrieved 16 August 2008 from https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCmnBjCtCgTBDU-u-6fqJhQNd24WBjTUdyghTQs_Bfy2gmiG4NiAgJYRrmVa6O4aivvVVI2Ilb0KnYxw069T1V62tZkm8CaZ9AQFIZF63tzEX8qWZjT33NrflJ5zmNDcB3uJguAN428HxF/s240/Human+Serum+Albumin+Image.jpg

It is a carbohydrate-free protein that makes up 55-65% of the total protein and has a molecular weight of 69,000. It helps to maintain oncotic plasma pressure and is also involved in transporting and storing of ligands. It is also a carrier of unconjugated bilirubin.

Conditions related to albumin


Hypoalbuminaemia
This occurs when albumin levels are lower than the reference range.
However, hypoalbuminaemia can be related to multiple causes.
They can be related to:

liver failure/disease
tissue damage (during burns)
Crohn's disease (malabsorption of amino acids)
nephrotic syndrome (proteinuria)
neoplastic disease (protein loss from the stools)

The most common cause is of course, liver failure.

When there is liver damage, the hepatocytes fail to produce albumin. this then leads to a drop in serum albumin levels. However, albumin levels are not a good indicator of liver failure in the early stages as it has a long half-life, which is about 20days.

Now I shall share with you how the LX 20 machine measures the serum levels of albumin in a sample.

We use a Bromcresol Purple reagent, otherwise known as BCP (we can also use Bromcresol Green, but most labs use BCP, and Bromcresol Green is good when testing animal serum) 5 microliters of the sample serum (from plain tube that has been centrifuged at 3250rpm for 5minutes) is injected into 570 microlitres of the reagent. They will then react and combine to form bromcresol purple albumin complex.

Albumin + BCP -----> Albumin-BCP Complex

The LX 20 then measures the change in absorbance at 600nm. This will be directly proportional to the concentration of albumin in the sample.

The reference range for albumin is 37-51g/L.

Therefore, to further diagnose liver failure, we have to run other tests as well as part of the liver function test and that includes testing levels of ALT, ALP, etc. For patients who are already diagnosed with liver failure, monitoring albumin levels allow us to see if their condition is worsening, and whether the medication prescribed has been effective. For example, if a liver failure patient's albumin levels continues to decrease over time, it probably indicates that more and more hepatocytes are continue to malfunction and have stopped synthesizing albumin.
Nevertheless, it is important that we run other tests as well to confrim before coming to any conclusion.

Week 4

Okay, so now here I am with my post for Week 4 of this 20-week process.
For the past 5weeks I've been under the Processing area of the hospital that I've been attached to.Now, when I say Processing, it does not refer to the Processing of tissues that we learn in Histo Tech. It refers to Processing samples in general.

Here in Processing, it is very admin-like. My section is the first section that ALL samples and specimens have to go through before they are sent out to the respective labs like Blood Bank, Micro lab, Immuno lab, etc.

We have a pneumatic tube system that allows us to receive samples from the Wards and Specialist Clinics, ICUs, etc. The samples are placed in cannisters which are attached with a microchip and are sent down to the lab. This saves time for the porters and health attendants to send them down. This is because not every room has samples to be sent down each time, and it will be a waste of time to send down just one sample every now and then.

The same principle goes for the sending back of results or rejected specimens (which have been mislabelled, or sent in the wrong type of tubes, etc). Results which are for outpatients and prisoners (yes, we have a prison ward here in this hospital and we do testing of their samples as well), or those which are confidential will be placed in an envelope and will be sent back to the respective wards/clinics via the pneumatic system too. At the same time, the results will also be faxed to the respective places. However in super urgent cases, there will be porters that send down samples.

The samples which are from the operating theatres, A&E department, Specialist Clinics, or those specifically marked as 'URGENT' will be given priority. The same goes for blood gas samples, which have to be tested within an hour. I do not know why such a short time limit though, for I've not been attached to the Routine section yet. For the prioritzed samples, we will scan the time and put them ahead regardless of how many samples that are already in the queue. However, for samples which are to be tested in the Micro lab and the Histo lab, we will put in their respective separate trays and will be brought to the separate labs.

The other specimens are then keyed into the LIS, and a barcode will be auto generated This is done by first scanning in the patient's information label and then keying in the tests that have been ordered by the doctor. There is a code for every test that is run here in the lab. But before confirming the test, it is our duty to verify that all the samples are labelled correctly, the amount of specimen is enough, and that the right type of specimen is sent (e.g. EDTA tube used for FBC and not plain tube). If any of this conditions are not met, we will have to call the nurse/doctor in-charge of the patient and notify them. We will then either discard or send back the rejected sample.

For the accepted samples and specimens, after keying in the tests ordered, a barcode will then be generated for every test. We will then have to paste the barcodes onto the various test tubes carefully. We must ensure that the name on the barcode matches the name of the patient. We must then paste accordingly to the test. This is by looking at the number on the barcode. For samples that will have to be processed at haematology section, the number will begin with "21" e.g. 2164552 and for Biochemistry, "10" e.g. 1045189
Sometimes, one tube may be shared for various tests, therefore we must only label the test tube with one barcode, which is from the main section. For example, biochemistry tests like tsting of Troponin T will be given priority over an immunoassay test, for example the testing of Theophylline. Therefore, we only paste the Biochem barcode onto the test tube and staple the Immunology barcode on to the request form. Since there is only one request form sent from the ward for many tests sometimes, we issue separate 'tickets' for the different sections should there be a request for multiple tests from multiple sites. Eg. Test for Blood Gases and Full Blood Count are done at different sites. Once labeling has been done, we send it out to the different sections. Our lab is small, so each section is just a few steps away from my site. From the LIS, we then do billing for the tests ordered, but I'm not sure how this is done as I cannot learn billing.

I must stress the importance of checking patient's details as a wrong results may be generated, and it may result in the wrong diagnosis and medication given which may be life threatening.

I also forgot to mention that not every single test are done here in my hospital. Certain tests are done at other hospitals like SGH. This is for the tests that are not always requested for.

Anyway, I hope this hasn't been too wordy, but I've tried my best to describe the major details that I think needs to be highlighted and brought across in order for you to comprehend my routine duties at work.

Do clarify your doubts with me should there be a need to. (:

PS, I miss the food from ITAS.

Elyana
TG01
0606676E

ISO 15189

1. Examination procedures :

* Procedure for carrying out the test ¹

* important requirement and must be reviewed regularly

* may be in the form of textbook instructions, journal article

2. Assuring the quality of examination procedures :

* have an IQC program to verify quality of patient test results¹(e.g. regular testing of QC materials and records¹ etc),

* participating in EQA programs

3. Post-examination process

* review of results before being reported

* used samples disposed in an environmentally and human-safe manner

4. Reporting of results

* used only approved forms

* results must be retained for a minimum period

* relevant information (e.g. reference range) must be included

5. Alteration and amendments of reports

* must be recorded and verified

(104 words excluding citations)

Reference

Cooper, Greg (2004). Preparing Your Laboratory to Certify or Accredit Under ISO 15189. Bio-Rad Laboratories. Retrieved June 16 2008 from http://www.sacb.org.sg/documents/PreparinglabforISO15189-GCooper.pdf