SPECIMEN COLLECTION AND PREPARATION
The D-dimer Rapid Test Cassette (Whole Blood/ Plasma) can be performed using whole blood (from venipuncture or fingerstick) or plasma.
To collect Fingerstick Whole Blood specimens:
Wash the patient’s hand with soap and warm water or clean with an alcohol swab. Allow to dry.
Massage the hand without touching the puncture site by rubbing down the hand towards the fingertip of the middle or ring finger.
Puncture the skin with a sterile lancet. Wipe away the first sign of blood.
Gently rub the hand from wrist to palm to finger to form a rounded drop of blood over the puncture site.
Add the Fingerstick Whole Blood specimen to the test by using a capillary tube:
Touch the end of the capillary tube to the blood until filled to approximately 25uL. Avoid air bubbles.
Place the bulb onto the top end of the capillary tube, then squeeze the bulb to dispense the whole blood to the specimen area of the test cassette.
To collect Whole Blood from venipuncture:
Collect blood from venipuncture with the anticoagulants tube (EDTA, Heparin, Citrate and Oxalate) and use it directly for the test.
Separate plasma from blood as soon as possible to avoid hemolysis. Use only clear non-hemolyzed specimens.
Testing should be performed immediately after the specimens have been collected. Do not leave the specimens at room temperature for prolonged periods. Plasma specimens may be stored at 2-8°C for up to half-day, for long term storage, specimens should be kept below -20°C. Whole blood collected by venipuncture should be stored at 2-8°C if the test is to be run within half day of collection. Do not freeze whole blood specimens. Whole blood collected by fingerstick should be tested immediately.
Bring specimens to room temperature prior to testing. Frozen specimens must be completely thawed and mixed well prior to testing. Specimens should not be frozen and thawed repeatedly.
If specimens are to be shipped, they should be packed in compliance with local regulations covering the transportation of etiologic agents.
DIRECTIONS FOR USE
Allow the test, specimen, buffer and/or controls to reach room temperature (15-30°C) prior to testing.
1. Exact QR Code from the QR code card for specific information of the test. Use only QR code card provided inside the test kits.
2. Bring the pouch to room temperature before opening it. Remove the test cassette from the sealed pouch and use it within one hour.
3. Place the cassette on a clean and level surface.
For Plasma specimen:
Hold the dropper vertically and transfer 1 drop of plasma (approximately 25uL) to the specimen well, then add 2 drops of buffer (approximately 80uL), and start the timer.
For Venipuncture Whole Blood specimen:
Hold the dropper vertically and transfer 1 drop of whole blood (approximately 25uL) to the specimen well, then add 2 drops of buffer (approximately 80 uL), and start the timer.
For Fingerstick Whole Blood specimen:
To use a capillary tube: Fill the capillary tube and transfer approximately 25 uL of fingerstick whole blood specimen to the specimen well of test cassette, then add 2 drops of buffer (approximately 80 uL) and start the timer. See illustration below.
4. Wait for the colored line is appeared. The result should be read with the LF Reader
at 10 minutes.
5. Do not interpret test results visually.
6. For the LF Reader installation, start up and complete instructions refer to the LF Reader User Manual. Operator must consult the LF Reader User Manual prior to use and become familiar with the processes and quality control procedures.
Note: It is suggested not to use the buffer, beyond 6 months after opening the vial.
A procedural control is included in the test. A colored line appearing in the control line region(C) is considered an internal procedural control. It confirms sufficient specimen volume, adequate membrane wicking and correct procedural technique.
Control standards are not supplied with this kit; however, it is recommended that positive and negative controls be tested as a good laboratory practice to confirm the test procedure and to verify proper test performance.
Sensitivity and Specificity
421 clinical specimens with known status of D-dimer above or below cut-off value of 500ng/mL collected from local hospitals were tested with D-dimer Rapid Test Cassette (Whole Blood/Plasma) in house. Results indicated relative sensitivity was 97.2%, relative specificity was 94.0%, and the overall accuracy was 96.4% compared with ITM.