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Vitamin D Test

Quantitative vitamin D measurement you can rely on.

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Only for Professional Use
The Welleo Vitamin D test measures 25‑hydroxyvitamin D levels from blood samples. Digital reading provides clear data to assess vitamin D status and support bone and metabolic health insights.
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Technical product

Vitamin D Test

Description

Vitamin D is a fat-soluble secosteroid that exists mainly as vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol), obtained from dietary sources, supplementation, and cutaneous synthesis after sunlight exposure. In the liver, vitamin D is hydroxylated to 25-hydroxyvitamin D [25(OH)D], the major circulating form and the biomarker most commonly used to evaluate vitamin D status. It can then be converted primarily in the kidney to 1,25-dihydroxyvitamin D, the biologically active form.

Vitamin D contributes to calcium and phosphorus homeostasis and supports bone mineralization, neuromuscular function, and overall skeletal metabolism. Quantitative measurement of 25(OH)D in blood is clinically useful for assessing vitamin D status, identifying low or excessive vitamin D levels, and monitoring response to supplementation or interventions related to bone and mineral metabolism.

Notice: Individual reference range and interpretation criteria are suggested to be established by each laboratory or clinical setting according to its population and applicable guidelines.

Intended use

The Welleo Vitamin D rapid test kit is intended for in vitro quantitative determination of 25-OH-VD in human serum, plasma, whole blood and peripheral blood samples. This test may help understand the metabolic changes of bone.

Principle

This kit utilizes the sandwich principle and fluorescence immunochromatography analysis technology to quantitatively detect the concentration of Vitamin D in human whole blood/plasma/serum samples.

The conjugate pad includes fluorescence particle-labeled anti-VD and goat anti-chicken IgY. The test line and control line on the nitrocellulose membrane are coated with anti-(Vitamin D antibody-antigen complex) and chicken IgY, respectively.

During testing, the Vitamin D antigen in the sample binds with the fluorescence nanoparticle-labeled anti-Vitamin D in the conjugate pad, forming the ""Vitamin D antibody-antigen"" immune complex.

This immune complex flows along the nitrocellulose membrane through chromatography to the absorbent paper pad at the end. On the test line, the pre-coated anti-(Vitamin D antibody-antigen complex) captures the immune complex, creating the double-antibody sandwich structure of antibody-antigen-antibody, and then generate fluorescence signal on the test line. The more Vitamin D present in the sample, the fluorescence intensity on the test line increase. The concentration of Vitamin D in the sample correlates positively with the fluorescence intensity on the test line. The concentration of Vitamin D in the sample is determined through testing and analysis by the Welleo Rapid Test Reader.

Technical dossier

Laboratory and clinical details

Materials provided
  • Main components (ref. SF150255, SF150256, SF150257):
  • The product is mainly composed of the following items:
  • Test cartridge | 15 tests | Detector Buffer | 15 units | Whole blood sampler | 15 units | Lancet | 15 units | Alcohol pad | 15 units | Biohazard bag 15 units | Instructions for use | 1 unit |
  • Note: The components of the different batches of kits are not interchangeable.
Materials needed but not provided
  • - Welleo Lateral Flow Reader (ref. Q1A-DUO-USB)
  • - Centrifuge (for Plasma/Serum only)
  • - Transfer pipette set (100 μL size)
  • - Specimen Collection Containers
Sample collection and preparation
  1. The test can be performed using serum, plasma, whole blood, or peripheral blood specimens.
  2. Whole Blood Collected by Venipuncture
  3. - Collect a whole blood specimen via venipuncture using standard phlebotomy procedures. Use a blood collection tube containing a suitable anticoagulant (EDTA is recommended).
  4. - It is recommended to test specimens immediately after collection. Do not leave specimens at room temperature for extended periods. If immediate testing is not possible, specimens may be stored at 2°C to 8°C.
  5. - Whole blood specimens stored at 2°C to 8°C for more than 2 days are not suitable for testing.
  6. Serum and Plasma
  7. - Separate serum or plasma from the blood as soon as possible to avoid hemolysis.
  8. - Testing should be performed immediately after specimen collection. Do not leave specimens at room temperature for extended periods.
  9. - Specimens may be stored at 2°C to 8°C for up to 7 days. For long-term storage, specimens should be kept at below –20°C.
  10. Peripheral Blood
  11. - Clean the fingertip with an alcohol pad. Remove the lancet cap and press to puncture the skin. Gently squeeze the finger to obtain an adequate drop of blood, then collect the sample into the blood collection tube.
  12. - Peripheral blood specimens may be stored at 2°C to 8°C for up to 7 days. For long-term storage, specimens should be kept at below –20°C.
Storage and stability
  • - Store the detector buffer at 2~30℃. The buffer is stable up to 24 months.
  • - Store test kit at 2~30℃, shelf life is up to 24 months.
  • - Test Cartridge should be used within 60 minutes after opening the pack.
Test procedure
  1. Download the app from the Google Play Store or Apple Store and sign in with your credentials. If sign up is needed, please contact your distributor. For specific operation of the instrument, follow the instructions on the reader.
  2. Step 1: Preparation
  3. The test and blood sample should be balanced at room temperature before the test. Open the foil bag, take out the test card, and place it on a table.
  4. Press on “+” button to start a new test, scan the QR code located in the test and follow the procedure. Select Patient ID, Sample ID, and sample type (if applicable).
  5. Step 2: Sampling
  6. Draw 10 μL of serum, plasma or whole blood with a transfer pipette and add it to the buffer tube. If using whole blood sampler open the diluent tube by peeling off the foil at the top and insert the blood collector completely into the diluent liquid.
  7. Step 3: Mixing
  8. Mix well the specimen with buffer for 10 seconds by tapping or inverting the tube.
  9. Step 4: Loading
  10. Take 80 μL of sample mixture and load it onto the sample well of the Test Cartridge. If using the whole blood sampler, place 3 drops in the sample well.
  11. Step 5: Testing
  12. Press Start Timer button and wait for the 15 minutes reaction time. A timer will be displayed on screen. The Welleo shall be connected to the Mobile App before this timer has expired.
  13. Insert the test into the Welleo. Once inserted, the animation on the Welleo App will change and you will be requested to extract the test at a constant speed. After some seconds, the test result will be displayed. If asked to repeat the reading, follow the feedback warning for proper action. If the test is not processed within 1 minute after the countdown concludes, the test will be considered invalid, and a new test must be used for retesting.
Quality control
  • This product used in conjunction with the Welleo Lateral Flow Reader contains internal control for routine quality control requirements. This internal control is carried out every time a patient sample is analyzed. This check indicates whether the test cartridge was inserted and read correctly using the Lateral Flow Reader. An invalid internal control result causes an error message in the analyzer indicating that the test should be repeated.
Performance characteristics
  • Blank detection limit
  • The blank detection limit ≤ 5.0 ng/mL
  • Accuracy
  • The relative deviation (Bias) is within ±15.0%.
  • Linear range
  • The linear range of determination is between 5.0 ng/mL and 100 ng/mL, and the linear correlation coefficient (R) is ≥ 0.98.
  • Repeatability
  • The coefficient of variation within batch≤ 15.0%.
  • The coefficient of variation between batches ≤ 20.0%.
Precautions
- This kit is for in vitro diagnostic use only.
- Do not mix components from different kit lots.
- Do not use test kit beyond the expiration date.
- This product should be applied by professionally trained staff working in certified laboratories at some remove from the patient and clinic at which the sample(s) is taken by qualified medical personnel.
- The test cartridge should remain in its original sealed pouch until ready to use.
- Do not use the test cartridge if the pouch is punctured or not well sealed, Discard after single use.
- Do not smoke, eat, or drink in areas in which specimens or kit reagents are handled.
- Blood specimens, used test cartridges, blood collectors and detector buffer vials are potentially infectious. Proper laboratory safety techniques, handing and disposal methods should be followed in accordance with standard procedures and relevant regulations observed by microbiological hazard materials.
- The results should be interpreted by the physician along with clinical findings and other laboratory test results.
- The test will be applied on a routine basis and not in emergency situations.
Limitations
- This test has been developed for testing human serum, plasma and whole blood specimen only.
- The results of this product should be evaluated with all clinical and laboratory data available. If 25-OH-VD test results do not agree with the clinical evaluation, additional tests should be performed.
- The false positive results may come from cross-reactions with some similar antibodies in blood; and similar epitopes from non-specific components in blood capturing fluorescent labeled antibodies.
- The false negative results may from some unknown substance blocking epitope adhering antibodies, unstable or degenerated 25-OH-VD that cannot be identified due to prolonged time and temperature and storage condition of sample and reagent.
- Other factors may interfere with this product and may cause erroneous results. These include technical or procedural errors, as well as additional substances in blood specimens.

How to use the Welleo tests