A complete analysis of the working principle of blood collection cards | Correct usage, storage techniques and experimental applications

1. What is a blood collection card?

A blood collection card (also known as a dried blood spot collection card, Dried Blood Spot, DBS) is a paper or cellulose-based card specially used for collecting, storing and transporting trace blood samples. It forms a dried blood spot by absorbing a small amount of blood (usually 50-100μL) and drying it naturally in the air, which is convenient for long-term storage and subsequent laboratory testing.

Main components
Filter paper substrate: high adsorption, no heavy metal pollution
Marking area: clear blood collection location (circle with a diameter of about 1cm)
Anti-fouling layer: prevent cross-contamination
Tearable design: convenient for laboratory sampling
II. Working principle of blood collection card

1. Blood adsorption and drying
   Collect blood by fingertip or heel puncture
   Blood drops on the marked area of ​​the card, naturally penetrate and spread
   Dry at room temperature for 2-4 hours (avoid direct sunlight)
2. Blood spot stabilization
   Hemoglobin, DNA, protein and other components are fixed in the fiber matrix
   Some collection cards contain chemical stabilizers (such as EDTA) to prevent degradation
3. Laboratory testing process
   Punching sampling: use a punch to take a blood spot of fixed diameter (3-6mm)
   Elution extraction: dissolve the target (such as DNA, antibodies, metabolites) with buffer
   Analysis and detection: PCR, ELISA, mass spectrometry, etc.
   III. Core advantages of blood collection card
   ✔ Micro-sampling: only 50-100μL (traditional blood collection tubes require 1-5mL)
   ✔ Strong stability: can be stored at room temperature for weeks to months (some tests up to 1 year)
   ✔ Convenient transportation: no cold chain required, reducing logistics costs
   ✔ Wide applicability: can be used for DNA, RNA, antibodies, metabolite detection
   ✔ Non-invasive/minimally invasive: especially suitable for newborns and field surveys

IV. Application areas of blood collection cards

1. Neonatal screening
   Phenylketonuria (PKU)

Congenital hypothyroidism

Genetic metabolic disease detection

2. Disease monitoring and epidemiological research
   HIV, hepatitis B, malaria antibody detection

New coronavirus serological survey

3. Genetic and molecular testing
   Parenthood testing

Pharmacogenomic analysis

4. Drug monitoring
   Detection of therapeutic drug concentration (such as anti-epileptic drugs)

Drug abuse screening

V. Steps for correct use of blood collection cards
Preparation before blood collection

Disinfect the blood collection site (fingertips/heels) with alcohol

Use a disposable blood collection needle

Blood dripping operation

Let the blood flow out naturally and touch the card marking area

Avoid repeated application to prevent hemolysis

Drying and storage

Place horizontally and air dry naturally (2-4 hours)

Put in a moisture-proof bag and add a desiccant

Transportation requirements

Avoid high temperature and humidity

It is recommended to use a sealed bag + shockproof packaging for long-distance transportation

VI. Common problems and solutions
❌ Problem 1: Uneven spread of blood spots
✅ Solution: Control the blood volume (do not exceed the circle range) and avoid repeated dripping

❌ Problem 2: Low detection sensitivity
✅ Solution: Ensure sufficient drying and avoid high temperature and high humidity environment

❌ Problem 3: Sample mildew
✅ Solution: Add mildew inhibitor or store at low temperature as soon as possible

VII. Product features of Huachenyang blood collection card
✔ Medical grade filter paper: meets WHO standards
✔ Pre-packaged desiccant: ready to use
✔ Multiple specifications:

Standard type (5-6 blood spots/card)

Newborn card (optimized design for heel blood sampling)

Anti-pollution type (with antibacterial coating)