Human ELISA kit
Frequently Asked Questions
How to ensure that the ELISA kit will not be damaged during transportation.
We will use air transportation to ensure that the test kits are delivered to you within one week. During this period, we used EPS foam boxes to store the ELISA kits and used dry ice to ensure the temperature was below 20°C.
Could you possibly offer a trial pack?
If you need antibodies, we can offer a 10-microliter trial pack for you, but you will be responsible for the shipping cost. We do not provide the ELISA kit packaging, but we can offer you an ELISA kit at a price much lower than the market rate for your use.
What Payment Methods Do You Support?
Currently, we support credit card payment, bank transfer, and third-party payment platforms (such as Alipay,Paypal.WeChat Pay, etc. International business will be adjusted according to relevant regulations).
Could you offer ELISA testing service for me?
Yes.If you purchase our test kits, we will offer a free ELISA testing service. If you provide the test kits yourself, we will charge a testing fee of $50.
Could you offer the service of customizing ELISA kits?
Yes, we offer custom ELISA kit services. Both the test factors and the detection sensitivity of the ELISA kits can be customized.
Why is your product so cheap?
We are the original manufacturer and this is our first attempt to enter the international market. We hope to establish trust with you as quickly as possible. Believe me, choosing to trust us will be the best decision for you.
Collection Methods of Blood Samples for ELISA Experiments
In China, we provide thousands of sets of enzyme-linked immunosorbent assay (ELISA) test kits to researchers every year. If the test factors are difficult to extract, we will offer testing services to the researchers. Due to the presence of numerous interfering factors in plasma, when we conducted tests using the same ELISA kits as the client’s samples, we found that all the test components could be detected. Therefore, collecting plasma samples is quite challenging. Here are the experiences we have gathered during the ELISA experiment process for collecting plasma samples. We hope they will be helpful to you.
Blood samples are among the most common specimens used in enzyme-linked immunosorbent assay (ELISA) experiments. Whether you are measuring cytokines, hormones, or disease biomarkers, the quality of your results depends heavily on how blood is collected, processed, and stored.
Based on collection conditions, whole blood can be divided into two categories: non-anticoagulated (for serum) and anticoagulated (for plasma). Serum is the yellowish liquid obtained after blood clotting, while plasma is collected by adding anticoagulants to prevent clotting. This guide details the proper methods for collecting both serum and plasma samples to ensure accurate and reproducible ELISA data.
Plasma Collection (Anticoagulated)
Plasma is obtained by mixing whole blood with an anticoagulant immediately after collection, then centrifuging to remove cells. The choice of anticoagulant depends on the target analyte and downstream application.
1. Heparin Anticoagulation
Mechanism: Heparin (a sulfated glycosaminoglycan) enhances antithrombin III activity, inhibiting thrombin and preventing clot formation.
Concentration: Typically 15–30 IU/mL blood (heparin:blood ratio ~1:30). It causes minimal dilution.
Advantages: Ideal for electrolyte testing (except sodium if using heparin sodium), biochemistry, and blood rheology. It does not interfere with most enzyme assays.
Precautions: Not suitable for white blood cell counts or differentials (heparin can aggregate leukocytes). For sodium measurement, use lithium heparin instead of sodium heparin.
2. EDTA Anticoagulation
Mechanism: EDTA (ethylenediaminetetraacetic acid) chelates calcium ions, blocking coagulation cascades.
Forms: K₂EDTA, K₃EDTA, or Na₂EDTA are common. K₂EDTA is recommended by the Clinical and Laboratory Standards Institute (CLSI) for hematology.
Concentration: 1.5–2.2 mg/mL blood.
Advantages: Preserves cell morphology; excellent for complete blood counts (CBC), blood smears, and flow cytometry.
Disadvantages: Not suitable for coagulation studies, trace element analysis (due to metal chelation), or PCR assays (may inhibit polymerases). Also, some metal-dependent enzymes (e.g., metalloproteases) may lose activity.
3. Citrate Anticoagulation
Mechanism: Sodium citrate binds calcium, preventing coagulation.
Concentration: 3.2% or 3.8% sodium citrate solution, mixed at a 1:9 ratio (anticoagulant:blood) .
Applications: Coagulation tests (PT, APTT, TT, fibrinogen). It is the CLSI-recommended anticoagulant for hemostasis testing.
Important: Tubes must be filled to the indicated volume to maintain the correct blood-to-anticoagulant ratio. After collection, invert gently 5–8 times.
Not for: Routine chemistry or immunoassays (citrate may interfere).
Serum Collection (Non-Anticoagulated)
Serum is obtained by allowing whole blood to clot naturally. The clot is then removed by centrifugation, yielding the liquid fraction. Below are three common collection tube types.
1. Plain Tubes (No Additives)
Description: These tubes have a silicone coating on the inner wall to prevent cell adhesion. Blood is collected and allowed to clot at room temperature for 30–60 minutes. After clot formation, centrifuge at 1000–2000 × g for 10–15 minutes and collect the supernatant (serum).
Applications: Serum biochemistry (liver/kidney function, myocardial enzymes, amylase), electrolytes (K⁺, Na⁺, Cl⁻, Ca²⁺, P³⁻), thyroid function, therapeutic drug monitoring, HIV testing, tumor markers, and serological immunoassays.
Alternative: Clean microcentrifuge tubes (e.g., EP tubes) can also be used; let blood clot naturally, then centrifuge.
2. Tubes with Clot Activator
Description: These tubes contain silica particles or other clot activators that accelerate coagulation by activating the intrinsic pathway. Blood clots typically within 30 minutes.
Benefits: Faster processing, ideal for emergency tests. Centrifuge as above to separate serum.
Applications: Routine and emergency clinical chemistry.
3. Tubes with Separator Gel and Clot Activator
Description: The inner wall is siliconized and coated with clot activator. Additionally, a thixotropic gel forms a physical barrier between serum and cells during centrifugation, ensuring complete separation without hemolysis.
Centrifugation: After clotting, centrifuge at 1000–2000 × g for 10 minutes; the gel migrates to form a stable barrier.
Applications: Same as plain tubes, but with improved serum stability and longer storage (up to 48 hours at 2–8°C).
Critical Considerations for Sample Quality
Centrifugation Speed and Time:
Serum/plasma should be separated within 2 hours of collection to avoid hemolysis and analyte degradation.
Use a refrigerated centrifuge at 4°C if possible, especially for labile analytes.
Storage Temperature:
Short-term (≤1 month): –20°C.
Long-term (≤6 months): –80°C.
Avoid repeated freeze-thaw cycles; aliquot samples before freezing.
Hemolysis, Icterus, and Lipemia:
Hemolyzed samples (visible red tint) can falsely elevate or suppress signals. If hemolysis is severe, recollect.
Icteric (yellow) and lipemic (milky) samples also interfere; use appropriate controls or purify if necessary.
Data on Stability:
A study showed that after 3 freeze-thaw cycles, IL-6 levels in serum decreased by 15–20% (compared to fresh samples). Always aliquot and use fresh aliquots for each assay.
Why Choose Yanda Bio for Your ELISA Needs?
At Yanda Bio, we understand that reliable results start with high-quality samples and equally high-quality reagents. Our ELISA kits, made in China, have been rigorously validated in the Chinese market and are now available to researchers in India and worldwide.
Extensive Menu: Over 6,000 detection targets covering immunology, oncology, neuroscience, metabolism, infectious diseases, and more.
Custom Sensitivity: Need higher sensitivity? We can adjust detection limits—like our Parathyroid Hormone 1‑34 kit, optimized from 3000 pg/mL to 60 pg/mL.
Affordable Pricing: Standard kits from just $120. Bulk orders welcome—contact us for competitive quotes.
Free Testing Service: Purchase our kits and send us your samples; we perform the ELISA for you.
Fast Delivery: Orders placed before 3:30 PM ship the same day; others ship next business day.
Summary
Proper blood sample collection is the foundation of accurate ELISA results. Whether you need serum or plasma, choose the right tube, follow recommended procedures, and store samples correctly.
When you’re ready to run your assay, trust Yanda Bio ELISA kits—manufactured in China with the quality and affordability that today’s research demands.