# Whole Blood Sample Processing for Lateral Flow Immunoassays
## Abstract
Direct whole blood analysis on lateral flow strips presents significant challenges due to matrix effects, hemolysis, and non-specific binding. This application note outlines sample processing strategies for POCT manufacturers developing lateral flow immunoassays that accept untreated whole blood specimens.
## Introduction
Whole blood is the preferred specimen type for point-of-care testing due to minimal sample preparation requirements. However, red blood cells, hemoglobin, and other blood components interfere with lateral flow strip performance, causing false positives, reduced sensitivity, and inconsistent flow rates.
Due Bio, established in 1987, has developed proprietary blood treatment buffers and membrane technologies that enable reliable whole blood testing on lateral flow strips. Our solutions are available for IVD Reagents OEM/ODM partners globally.
## Materials Required
– Whole blood collection tubes (EDTA or heparin)
– Blood treatment buffer (Due Bio Cat# BTB-01)
– Lateral flow strips with sample pad treatment
– Micropipettes (10-100 μL range)
– Timer
– Positive and negative control samples
## Step-by-Step Protocol
1. **Blood Collection**: Collect 100 μL whole blood into EDTA or heparin tube. Mix gently by inversion (3-5 times). Process within 4 hours of collection.
2. **Sample Treatment**: Add 100 μL blood to 200 μL blood treatment buffer (1:2 ratio). Mix by pipetting up and down (5 times). Incubate at room temperature for 2 minutes.
3. **Application**: Apply 80 μL treated sample to the sample pad of the lateral flow strip. Ensure complete absorption before proceeding.
4. **Incubation**: Allow strip to develop at room temperature (15-30°C) for 15 minutes. Do not read before or after the specified time window.
5. **Result Interpretation**: Read visually or with dedicated reader. Test line intensity correlates with analyte concentration. Control line must appear for valid results.
## Troubleshooting
**Q: Test line appears weak or absent?**
A: Check blood treatment buffer expiration date. Ensure proper 1:2 dilution ratio. Verify sample volume (80 μL). High analyte concentrations may cause hook effect—dilute sample 1:10 and retest.
**Q: Background staining on membrane?**
A: Hemolysis during sample collection. Avoid vigorous mixing. Ensure blood treatment buffer is at room temperature before use. Check strip storage conditions (4-30°C, dry).
**Q: Inconsistent flow rate?**
A: High hematocrit (>55%) slows flow. For extreme hematocrit values, increase blood treatment buffer ratio to 1:3. Store strips horizontally to prevent membrane compression.
## Conclusion & OEM/ODM Services
Reliable whole blood testing on lateral flow strips requires optimized sample treatment and membrane chemistry. Due Bio has been supporting POCT manufacturers since 1987 with blood-compatible reagents, lateral flow strips, and complete assay development services.
For IVD Reagents OEM/ODM inquiries, contact: **medtiger@foxmail.com**
Visit: www.duebio.com