NK VUE Information for Medical Professionals


Blood Collection Procedure

Because NK Vue Tube is a function assay, the sample collection requires some additional steps and precautions in comparison to most blood tests.

  1. Remove the NK VUE Tube from the refrigerator just before use for blood collection. Write patient’s name, date, and collection time on the space provided on the tube’s label.

  2. Insert needle into arm, angling it towards the floor as much as possible to facilitate blood flow. Take NK Vue tube, holding by the cap, and plug into the needle collection system. (Try to hold the tube barrel as little as possible to avoid warming the contents of the NK Vue tube. Blood flow will be slower than expected since only 1 mL is being collected. Before unplugging the NK Vue tube from the needle, wait 3-4 seconds after you note that the blood has stopped flowing into the tube.)

  3. Unplug the NK Vue tube from the needle holder without removing the needle from the arm, and verify that the collected volume is correct by holding the tube vertically. If the blood is not within the black bar, immediately collect another 1 mL sample using a new NK Vue tube.

  4. Volume collected may be influenced by patient vein being used or patient blood pressure. Adjust blood draw technique accordingly. If after the second try, the blood level is still not within the black bar, see Tips and Tricks below and use a second venipuncture point to draw blood.

  5. Mix the contents by gently rolling and inverting the tube 10-15 times, ensuring that tube walls have been entirely soaked in blood and contents is thoroughly mixed and homogeneous. DO NOT shake tubes nor use a tube roller for the mixing step.

  6. Start incubation at 37°C as soon as possible (within 15 min), placing the tube UPRIGHT within the incubator.

Tips and Tricks

If for any reason a direct needle blood collection system cannot be used, the following instructions must be considered: If a syringe is used, briefly spin NK VUE tube beforehand to collect contents at its bottom, and remove NK VUE tube cap/stopper assembly. Then, slowly transfer 1 mL blood into the NK VUE Tube, as to avoid damaging cells during transfer, and re-cap tube firmly.

If a butterfly needle needs to be used, it is important to first purge the tubing by collecting some blood into a heparinized blood collection tube (4–5 drops) (do not use any other type of blood collection tube, like citrate or EDTA, etc., for this pre-draw). Immediately following the pre-draw, switch to the NK VUE Tube. This process will ensure collection of the proper volume into the NK VUE Tube, calibrated to draw 1 mL of whole blood.

Here is a video for this step, which can also be viewed in our resource section.



The Plasma sample can either be prepared at the clinic or at the Lab.

The next day, after incubating the NK VUE tube with blood for 20-24hs at 37°C, the plasma sample needs to be prepared to be sent to a clinical laboratory for analysis.

  1. Refrigerate NK Vue tube and ship to lab at cool temperature (2-8°C) within 3days

  2. Carefully remove clear supernatant and place into a 1.5 mL microcentrifuge tube.

  3. Optional (for a cleaner sample): Spin in a microcentrifuge for 1 minute at 11,500g. Transfer clear supernatant into a new microcentrifuge tube. Do not collect insoluble material. Cap tubes well.

  4. Freeze at -20°C or below for longer storage.

Here is a video for this step, which can also be viewed in our resource section.


You can view our cheat sheet containing the different tips and precautions for the blood collection, which can be also be downloaded in our resources section.

Consult our NK Vue Tubes product insert for a detailed explanation, which can be also be downloaded in our resources section.