LIVER FUNCTION TEST (LFT)
The liver function test is carried out using the Reflotron. The machine determines the concentration of particular enzyme and proteins in the liver by the use of strips. Liver function test comprises of the Total Billirubin, glutamate oxaloacetate transaminase (GOT), Glutamate pyruvate transaminase (GPT), and Alkaline phosphate (ALP).
ALKALINE PHOSPHATASE (ALP) IN LIVER FUNCTION TEST
Alkaline phosphatase (ALP) is present in various human tissues e.g liver, bone, intestine and placenta. The most frequent causes of elevated total ALP activity in serum are diseases of the liver and biliary tract. When measured together with other enzymes such as GOT, GPT, ALP permits the differential-diagnostic identification of cholestatic disorders.
Elevated levels of ALP are found in various types of bone disease and disorders of bone metabolism; e.g paget’s disease, osteomalacia, rickets hyperparathyroidism. Elevated ALP levels in malignant disorders may be due either to the presence of tumour phosphatises or to elevation of hepatic and bone ALP.
Increased osteoblastic activity such as that occurring in the skeletal growth phases of childhood and adolescence is associated with ALP levels that are elevated but fall again following puberty. Elevated levels of alkaline phosphatase observed during the third trimester of pregnancy are produced particularly by the placental isoenzyme
After application to the test strip, the sample flows into the reaction zone, in the case of blood after separation of the erythrocytes from the plasma. ALP hydrolyzes o-cresol-phthalein and transfers the phosphate group to the acceptor molecule methylglucamine.
The coloured hydrolysis product o-cresol-phthalein that is produced per unit of time under alkaline conditions is directly proportional to alkaline phosphatase activity:
o-crestolphthalein phosphate + methylglucamine o-cresolphathlein + methylglucamine phosphate.
Dye formation is determined kinetically at 370c as a measure of the enzyme activity of ALP. The result is displayed after approximately 135 seconds in U/l.
Sample collection for LFT
Blood sample is collected into the lithium heparin tube or Ethylene diamine tetra acetic tube.
Testing procedure for LFT (GOT, GPT, ALP)
Additional material required (not supplied): Reflotron instrument; Reflotron pipette and pipette tips or capillary pipette, controls, usual laboratory equipment for collecting blood.
- Switch on the instrument.
- When the display shows “READY”, remove a rest strip from the container.
- Unwrap the strip, taking care not to bend it.
- Using the reflotron pipette, for example, draw sample material into the pipette (avoiding bubbles) and apply as drop to the centre of the red application zone, taking care not to touch the application zone with the pipette tip. Required volume of specimen for application 30nl
- With the sliding cover or flap open, place the test strip on the guide within 15 seconds and slide forward horizontally until it locks intro place
- Close the sliding cover or flap.
- The instrument displays “ALP” to confirm that it has correctly read in the test-n specific magnetic code. The display shows the number of seconds left before the result is displayed.
- ALP activity is calculated automatically from the readings taken using function and conversion factors that are entered in the instrument via the magnetic strip on the underside of each test strip. The enzyme activity is shown in U/l
- Remove the used test strip from the reflotron and dispose of it according to your laboratory’s procedure.
Below is the reference range for male and female;
|Glutamate pyruvate transaminase(GPT)||Up to 41||Up to 32|
|Alkaline Phosphate(ALP)||Up to 270||Up to 240|