Each batch of reagent undergoes rigorous quality

control at various stages of manufacture for its sensitivity

and performance.

Storage and Stability

a. Store the reagent at 2-8°C. Do not freeze.

b. The shelf-life of the reagent is as per the expiry date

mentioned on the reagent vial label.

c. The reconstituted Lyoplastin reagent can be used

for 10 days when stored at 2–8°C provided it is not

contaminated.

d. It is strongly recommended that enough reconstituted

reagent should be retrieved for the days use and the

unused reagent should be immediately replaced to

2–8°C.

Principle

Tissue thromboplastin in the presence of calcium activates

the extrinsic pathway of human blood coagulation

mechanism. When Lyoplastin reagent is added to normal

citrated plasma, the clotting mechanism is initiated,

forming a solid gel clot within a specified period of time. The

time required for clot formation would be prolonged if there

is acquired or congenital deficiency of factors/factor activity

in the extrinsic pathway of the coagulation mechanism or

reduction in the activity of vitamin K dependent clotting

factors during oral anticoagulant therapy.

Note

1. In vitro diagnostic reagent for laboratory and

professional use only. Not for medicinal use.

2. Lyoplastin reagent is not from human source, hence

contamination due to HBsAg and HIV is practically

excluded.

3. It is very important that scrupulously clean and dry

micropipette tips be used to aspirate/dispense the

reagent.

4. Avoid exposure of the Lyoplastin® reagent to elevated

temperatures, contamination and undue stress

due to high and low temperature exposure cycles.

Immediately replace reagent cap after use and store

at recommended temperatures only.

Additional Material Required

12 × 75 mm test tubes (plastic tubes are preferred),

0.1 mL and 0.2 mL precision pipettes, 1 mL precision

pipette, distilled water, stop watch, water bath or heating

block at 37°C, fresh normal plasmas for establishing MNPT.

Reagent Preparation

Bring the lyoplastin® reagent to room temperature

(25–30°C) prior to reconstitution. Lyoplastin® reagent

is reconstituted with 3 mL de-ionized, distilled water as

follows: (a) Add accurately 3 mL of distilled water to the

lyophilized Lyoplastin® reagent, (b) Gently mix to dissolve,

(c) Keep for 10 minutes and mix again gently ensuring

complete resuspension of the lyophilized reagent. Avoid

froth formation, (d) Thorough mixing should be ensured

before withdrawing material every time for test purposes.

Sample Collection and Preparation of PPP

Though no special preparation of the patient is required

prior to sample collection by approved techniques, it is

preferable that patients are not heavily exercised before

blood collection. Fasting or only light non-fatty meals prior

to blood collection provide samples with a desirable lower

opacity. Withdraw blood without undue venous stasis or

frothing into a plastic syringe fitted with a short needle of 19

to 20 SWG. The venipuncture must be a ‘clean’ one and, if

there is any difficulty, take a new syringe and needle and try

another vein. Transfer the blood into anticoagulated tubes,

after detaching the needle from the syringe. Do not delay

mixing blood with anticoagulant. Avoid foam formation

during mixing.

Mix exactly nine parts of freshly collected blood

with one part of Trisodium citrate (0.11 mol/L, 3.2%) or

Profact available from Tulip. For occasional patients

with hematocrit less than 20% or greater than 55%,

this ratio must be readjusted to ensure valid results.

Centrifuge immediately for 15 minutes at 1500–2000 rpm

(approximately 1500 g) on a laboratory centrifuge and

transfer the plasma into a clean test tube. It should be

ensured that the plasma is free from platelets (PPP). Cap

the test tubes to prevent deterioration of samples. Plasma

must be tested preferably immediately. However, if the

Clinical Hematology: Bleeding Disorders 289

specimen are held at 22–24°C then they may be tested

within 2 hours and if the specimen is held at 2–4°C then

they may be tested within 3 hours.

Test Procedure