Author Archive: Guanliyuan

Guidelines to Avoid Cross-Contamination of Blood Samples

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Guidelines to avoid blood sample cross-contamination are critical for ensuring accurate test results in clinical, forensic, and research settings. Cross-contamination—transfer of foreign material between samples—renders data unreliable, so these protocols focus on sterile practices and strict workflow controls.

Core Guidelines

  • Sterile Tool Use: Employ single-use, pre-sterilized采血工具 (needles, vacutainers, lancets); discard after each sample.
  • Hand & PPE Protocols: Wash hands between samples; wear fresh gloves, masks, and gowns to prevent skin contact transfer.
  • Sample Isolation: Use separate workspaces for each sample; seal containers immediately after collection to avoid spillage.
  • Decontamination: Clean benchtops, equipment, and surfaces with disinfectant (e.g., 70% ethanol) between samples.
  • Proper Labeling: Tag samples with unique IDs before collection; never reuse labels or mix sample containers.

Key Features

  • Preventive Focus: Stops contamination at every workflow stage, not just post-event.
  • User-Friendly: Simple, actionable steps for personnel with basic training.
  • Result Reliability: Eliminates false positives/negatives from external material transfer.
  • Compliance-Aligned: Meets standards like CLIA, ISO 15189 for lab accreditation.

Scope & Applications

  • Clinical Diagnostics: Ensures accurate patient blood tests (CBC, chemistry panels) for treatment decisions.
  • Forensic Science: Preserves blood evidence integrity for DNA profiling and legal admissibility.
  • Research Labs: Maintains purity of blood samples for experimental consistency.
  • Blood Banking: Prevents donor blood contamination during collection and storage.

Sample Information Recording and Management Techniques

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Sample information recording and management techniques ensure traceability, integrity, and accessibility of sample data across research, clinical, and forensic fields. These methods combine standardized documentation and digital tools to track samples from collection to analysis, mitigating errors and supporting compliance.

Core Techniques

  • Standardized Labeling: Use unique identifiers (barcodes/QR codes) with key info (ID, date, type, collector) for consistent sample tagging.
  • Digital Databases: Cloud-based or local systems (LIMS) store sample metadata, enabling search, update, and audit trails.
  • Chain-of-Custody Logs: Document every sample transfer with timestamps, personnel signatures, and location details.
  • Automated Tracking: RFID tags or barcode scanners streamline data entry, reducing manual errors and saving time.

Key Features

  • Traceability: Full visibility of sample lifecycle for accountability and reproducibility.
  • Error Reduction: Standardized forms and automation minimize data entry mistakes.
  • Compliance: Aligns with regulatory standards (FDA, GDPR) for audit readiness.
  • Accessibility: Authorized users access real-time data remotely, supporting collaboration.

Scope & Applications

  • Clinical Labs: Manage patient samples for diagnostics and treatment monitoring.
  • Research: Track experimental samples in biotech, environmental, and pharmaceutical studies.
  • Forensics: Maintain evidence sample integrity for legal proceedings.
  • Biobanking: Organize large-scale sample collections for long-term research use.

Field Blood Collection & Submission

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Field blood sample collection and submission require standardized protocols to ensure sample integrity, safety, and compliance—critical for remote research, forensics, and public health. These procedures address challenges like limited resources, environmental variability, and transport delays, guiding personnel from collection to lab handoff.

Core Standard Procedures

  1. Preparation: Gather sterile single-use tools (vacutainers/lancets), PPE, preservatives, and labeling materials. Check tool expiry and calibrate if needed.
  2. Collection: Disinfect the site, draw blood using proper technique (venipuncture/capillary), and add preservatives (EDTA/ethanol) per sample type. Mix gently to avoid clotting.
  3. Labeling: Mark samples with unique ID, date, time, collector, and sample type. Attach labels securely to containers.
  4. Preservation/Transport: Store at 2–8°C (coolers with ice packs) or use dried blood spot cards for room-temperature transport. Avoid extreme temps.
  5. Submission: Complete chain-of-custody forms, package samples in biohazard containers, and ship to lab with tracking—document all transfers.

Key Features

  • Field-Adaptable: Works with limited equipment and variable environments.
  • Integrity-Focused: Minimizes contamination, hemolysis, and degradation.
  • Compliant: Aligns with global standards (ISO, CLIA) for lab acceptance.
  • Safe: Emphasizes PPE and biohazard handling to prevent pathogen transmission.

Scope & Applications

  • Epidemiology: Remote disease surveillance and outbreak response.
  • Forensics: Crime scene blood evidence collection in rural/remote areas.
  • Wildlife Research: Blood sampling for animal conservation and health monitoring.
  • Global Health: Blood testing in resource-poor regions for public health initiatives.

Long-Term Preservation and Microbial Protection of DNA Samples

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Long-term DNA sample preservation requires balancing stability against degradation and microbial contamination, critical for biobanking, research, and forensic archives. Microbes (bacteria, fungi) secrete nucleases that break down DNA, while environmental factors like moisture and temperature accelerate decay. Effective strategies combine physical storage conditions, chemical protectants, and contamination-control protocols to maintain DNA integrity for years to decades.

Core Preservation & Protection Methods

  • Cryopreservation: Storing samples at -80°C (freezers) or -196°C (liquid nitrogen) halts microbial growth and enzymatic activity. Ideal for high-value samples but requires specialized equipment.
  • Dry Preservation: Using desiccants (silica gel) or matrices like FTA cards to remove moisture, inhibiting microbial proliferation. Enables room-temperature storage for dried blood/spit samples.
  • Chemical Protectants: Adding EDTA (nuclease inhibitor), ethanol, or commercial preservatives to liquid samples to suppress microbes and prevent hydrolysis.
  • Sterile Handling: Aseptic techniques (gloves, sterile tools) during collection/processing reduce initial microbial load, preventing contamination before storage.

Key Features

  • Microbial Inactivation: Methods target microbe growth and nuclease activity to avoid DNA breakdown.
  • Environment Control: Regulates temperature/moisture to slow chemical degradation pathways.
  • Cost-Efficiency: Dry preservation offers low-cost, low-maintenance storage vs. cryopreservation.
  • Sample Versatility: Works for liquid (blood, saliva), solid (tissue), and environmental DNA samples.

Scope & Applications

  • Biobanking: Long-term storage of human/animal DNA for clinical research and personalized medicine.
  • Forensics: Archiving crime scene DNA evidence for cold case investigations and legal proceedings.
  • Environmental Science: Preserving eDNA samples from soil/water for biodiversity monitoring over time.
  • Agriculture: Storing crop/livestock DNA for breeding programs and pathogen resistance research.

Sterile Single-Use Blood Collectors

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One-time use sampling tools have become the gold standard for safe and standardized blood collection across clinical, forensic, and research settings. Designed to eliminate cross-contamination risks and ensure consistent sample quality, these single-use devices replace reusable equipment (e.g., glass syringes, metal lancets) that requires rigorous cleaning and sterilization—processes prone to human error. From needles and vacutainers to lancets and collection tubes, each tool is pre-sterilized, calibrated, and engineered for a specific function, adhering to global standards (e.g., ISO 13485, FDA regulations) to guarantee reliability. Their adoption has significantly reduced the transmission of bloodborne pathogens (e.g., HIV, hepatitis B/C) and improved the reproducibility of blood-based tests, making them indispensable for modern healthcare and scientific practice.

Core Tool Types & Components

These tools are modular and tailored to different blood collection needs, ensuring versatility without compromising safety:
  • Vacutainer Systems: The most widely used tools, consisting of a pre-sterilized needle, a plastic holder, and vacuum-sealed collection tubes. Tubes are available with different additives (EDTA for hematology, citrate for coagulation, serum separators for chemistry tests) to preserve sample integrity for specific analyses. The vacuum ensures precise blood volume draw, reducing overfilling or underfilling errors.
  • Lancet Devices: Used for capillary blood collection (e.g., fingersticks for glucose testing or pediatric samples). These spring-loaded, single-use devices feature a sharp, sterile needle that penetrates the skin to a controlled depth (0.3–2.0mm), minimizing pain and reducing the risk of injury compared to reusable lancets. Post-use, the needle retracts into the device for safe disposal.
  • Blood Collection Bags: For large-volume blood draws (e.g., blood donations), these sterile, plastic bags contain anticoagulants (e.g., CPDA-1) and are equipped with needle protectors and ports for sample aliquoting. They are designed to prevent leakage and ensure compatibility with blood banking equipment.
  • Accessory Tools: Pre-sterilized alcohol swabs for skin disinfection, gauze pads for hemostasis, adhesive bandages, and biohazard disposal containers. These accessories complement the primary tools, supporting a complete, standardized collection workflow.

Key Features Ensuring Safety & Standardization

  • Pre-Sterilization: All tools undergo ethylene oxide (EtO) or gamma radiation sterilization, with sterility indicators (e.g., color-changing labels) to confirm effectiveness—eliminating cross-contamination from previous use.
  • Fixed Calibration: Needle gauges (18–25G for vacutainers, 28–33G for lancets) and vacuum levels are factory-set to ensure consistent blood draw volume and minimize hemolysis (red blood cell damage) that can skew test results.
  • Sharps Injury Prevention: Many tools (e.g., retractable lancets, safety needles) feature built-in mechanisms that cover or retract the needle after use, reducing the risk of needlestick injuries to healthcare workers by up to 80%.
  • Traceability: Each tool is labeled with a lot number and expiry date, enabling batch tracking and recall if quality issues arise—supporting regulatory compliance.

Scope & Applications

  • Clinical Healthcare: Routine blood tests (CBC, chemistry panels), blood donations, and point-of-care testing (POCT) in hospitals, clinics, and physician offices.
  • Forensic Science: Collection of blood evidence from crime scenes or suspects for DNA profiling, with single-use tools ensuring sample integrity and avoiding cross-contamination of evidence.
  • Public Health & Epidemiology: Large-scale blood screening campaigns (e.g., hepatitis B surveys, COVID-19 antibody testing) in remote or resource-limited regions, where standardized tools ensure reliable data.
  • Veterinary Medicine: Blood collection from animals for diagnostic testing, with species-specific lancet depths and tube additives to accommodate different blood volumes and properties.

Enhanced Double-Hole Blood Sample Collection Card Kit Overview

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The Enhanced Double-Hole Blood Sample Collection Card Kit is an advanced solution designed to streamline and improve the efficiency of blood sample collection, preservation, and downstream analysis. Building on the foundational benefits of traditional dried blood spot (DBS) cards, this enhanced kit features a dual-hole design that enables simultaneous collection of two independent blood samples on a single card—addressing the need for duplicate testing, multi-assay compatibility, or backup samples in clinical, forensic, and research settings. Integrated with upgraded preservation reagents and user-centric accessories, the kit ensures long-term DNA/biomarker stability while simplifying workflow for field and lab personnel alike.

Kit Composition & Design Features

The kit is thoughtfully engineered with components that prioritize sample integrity, operational ease, and versatility:
  • Double-Hole Collection Card: A cellulose-based card with two distinct, labeled sample wells (5–8mm diameter each) separated by a hydrophobic barrier. This prevents cross-contamination between samples while allowing side-by-side collection. The card is impregnated with enhanced preservation reagents—including chaotropic salts, EDTA, and antimicrobial agents—that lyse cells, inactivate nucleases, and inhibit microbial growth to preserve DNA and proteins for up to 8 years at room temperature.
  • Sample Application Tools: Sterile capillary tubes (10μL/20μL) for precise blood volume measurement, disposable transfer pipettes, and a calibrated dropper to ensure consistent sample loading into each hole. The tools reduce human error and ensure uniform sample spreading within each well.
  • Preservation & Storage Accessories: Moisture-resistant foil pouches with pre-loaded silica gel desiccants to maintain card dryness during storage/transport, tamper-evident seals for chain-of-custody tracking, and a waterproof storage box to protect cards from environmental damage.
  • Documentation & Safety Supplies: Printed labels for sample identification (patient ID, date, time), chain-of-custody forms, disposable nitrile gloves, and absorbent pads for spill cleanup—supporting compliance and user safety.

Key Functional Advantages

  • Dual-Sample Efficiency: Eliminates the need for multiple single-hole cards by enabling two independent samples per card, reducing kit costs and storage space by up to 50%.
  • Cross-Contamination Prevention: Hydrophobic barriers between holes and sterile application tools ensure no sample mixing, critical for duplicate testing or multi-analyte workflows (e.g., DNA genotyping and infectious disease screening).
  • Enhanced Biomarker Stability: Upgraded reagents improve preservation of both DNA and proteins, expanding compatibility with downstream applications like PCR, ELISA, and next-generation sequencing (NGS).
  • Field-Friendly Workflow: No refrigeration required, lightweight packaging (150–200g per kit), and clear, pictorial instructions make it suitable for remote or resource-limited settings.

Scope & Applications

  • Clinical Diagnostics: Pediatric or geriatric blood sampling for duplicate genetic testing (e.g., newborn screening, rare disease diagnostics) or simultaneous infectious disease and biomarker analysis.
  • Forensic Science: Collection of blood evidence from crime scenes for parallel DNA profiling (one sample for analysis, one for backup) while maintaining chain-of-custody integrity.
  • Epidemiological Research: Large-scale surveys in remote regions, where dual samples support both immediate testing and long-term biobanking for future studies.
  • Animal Health & Veterinary Science: Collection of small blood volumes from livestock or wildlife for concurrent pathogen detection and genetic diversity analysis.

Usage Best Practices

To maximize performance: Apply 10–20μL of blood to each hole (avoid overloading to prevent barrier breach); air-dry the card horizontally for 60–90 minutes before sealing in desiccated pouches; store at 15–25°C away from direct sunlight; and use a sterile punch tool to extract sample discs from each hole for downstream analysis.

FTA Cards for Blood Sample Preservation and DNA Analysis

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FTA cards (short for “Fixative, Transport, and Analysis cards”) are specialized cellulose-based matrices designed for the long-term preservation of blood samples and subsequent DNA analysis. Developed to address the challenges of traditional liquid blood storage—such as refrigeration requirements, microbial growth, and sample degradation—FTA cards integrate chemical reagents (e.g., chaotropic salts, chelating agents, and antimicrobial compounds) that immediately fix blood cells, inactivate nucleases, and prevent microbial contamination. This technology has revolutionized field-based blood collection, enabling samples to be stored and transported at room temperature for years while maintaining high-quality DNA suitable for PCR, genotyping, and sequencing. From clinical diagnostics to forensic investigations and epidemiological surveys, FTA cards have become a staple tool for reliable, cost-effective blood DNA preservation.

Working Principle & Operation Steps

FTA cards rely on a multi-step chemical process to preserve blood samples and stabilize DNA, with a straightforward workflow suitable for field or lab use:
  1. Sample Application: A small volume of whole blood (50–100μL, approximately 1–2 drops) is spotted directly onto the labeled circles of the FTA card. For dried blood spots (DBS), the card is held horizontally to ensure uniform spreading without pooling.
  2. Fixation & Preservation: The card’s reagents immediately lyse blood cells, release DNA, and denature proteins (including nucleases that degrade DNA). Chaotropic salts disrupt cell membranes, while chelating agents (e.g., EDTA) bind metal ions required for nuclease activity, and antimicrobials prevent bacterial/fungal growth.
  3. Drying: The card is air-dried at room temperature for 1–2 hours (or 30 minutes in a fume hood). Drying is critical—moisture残留 can lead to sample degradation or cross-contamination. The card is then stored in a sealed plastic bag with a desiccant to absorb ambient moisture.
  4. DNA Extraction for Analysis: A small punch (2–3mm diameter) is taken from the blood-spotted area using a sterile punch tool. The punch is washed 2–3 times with FTA purification buffer (or TE buffer) to remove reagents and residual hemoglobin, then dried. The purified punch is directly added to PCR reactions, as the DNA remains bound to the card matrix and is released during PCR thermal cycling.

Key Features

  • Room-Temperature Stability: Preserves DNA for up to 10+ years at 15–25°C, eliminating the need for refrigeration or freezers during storage/transport.
  • Microbial & Nuclease Inactivation: Integrated reagents prevent microbial growth and nuclease activity, ensuring DNA integrity even in warm or humid conditions.
  • Minimal Sample Volume: Requires only small blood volumes, making it ideal for pediatric samples, wildlife studies, or resource-limited settings.
  • Cost-Effective & Portable: Lightweight, compact, and cheaper than liquid storage tubes, reducing shipping costs and logistical burdens for fieldwork.

Scope & Applications

  • Clinical Diagnostics: Storage of patient blood samples for genetic disease testing (e.g., sickle cell anemia), infectious disease surveillance (e.g., HIV, malaria), and pharmacogenomics.
  • Forensic Science: Preservation of blood evidence from crime scenes (e.g., dried blood stains) for DNA profiling, with long-term stability supporting cold case investigations.
  • Epidemiological Research: Large-scale blood collection in remote or resource-poor regions to study disease prevalence, genetic diversity, or population health trends.
  • Wildlife Conservation: Collection of small blood samples from endangered species for genetic monitoring, parentage analysis, or disease screening without requiring immediate lab access.

DNA Collection Card for Blood Samples

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The Standard DNA Blood Sample Collection Card Kit is designed for efficient and reliable collection of blood samples for DNA analysis. The kit includes a specially treated collection card, which absorbs and stabilizes blood samples, ensuring DNA integrity during storage and transport. It is ideal for forensic investigations, genetic testing, and medical diagnostics. The blood is collected directly onto the card, eliminating the need for liquid sample containers, and reducing the risk of contamination. This kit supports PCR, sequencing, and genotyping, making it a vital tool for accurate DNA profiling.

Key Features:

  • Specially treated collection cards for blood absorption

  • Prevents contamination and preserves DNA integrity

  • Supports PCR, sequencing, and genotyping

  • Convenient, portable, and easy to use

Application Scope:

  • Forensic blood sample collection

  • Genetic testing and medical diagnostics

  • Criminal justice and legal use

  • DNA transport and storage

Tube Technology for Preventing Sample Decay and Mold

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Tube technology designed to prevent sample decay and mold growth is critical for preserving the integrity of biological evidence. These tubes are equipped with moisture-resistant seals and anti-mold additives that inhibit microbial growth, ensuring that DNA samples remain viable for long-term storage. They are ideal for storing blood, saliva, and touch DNA collected at crime scenes or during medical investigations. With optimal ventilation and desiccant features, these tubes safeguard against contamination, preserving high-purity DNA for PCR, sequencing, and genotyping, even from degraded samples.

Key Features:

  • Moisture-resistant seals to prevent decay

  • Anti-mold additives for long-term preservation

  • Suitable for PCR, sequencing, and genotyping

  • Effective for storing degraded or minimal DNA samples

Application Scope:

  • Forensic evidence collection and storage

  • Long-term biological sample preservation

  • Crime scene and medical sample transport

  • DNA analysis and genetic research

Techniques to Improve Trace Sample Extraction Efficiency

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Improving trace sample extraction efficiency is crucial in forensic and DNA analysis, especially when dealing with minimal or degraded samples. Techniques such as enhanced swabbing methods, optimized buffer solutions, and specialized collection tools maximize DNA recovery from trace evidence like blood, saliva, or touch DNA. Advanced filtration and elution methods increase the yield of DNA, ensuring high-purity samples for PCR, sequencing, and genotyping. These techniques are especially useful in cold-case investigations and crime scene processing, providing reliable results even from low-concentration evidence.

Key Features:

  • Enhanced swabbing and buffer solutions for better recovery

  • Optimized filtration and elution methods

  • High-purity DNA for PCR, sequencing, and genotyping

  • Effective for minimal or degraded samples

Application Scope:

  • Forensic crime scene analysis

  • Cold-case investigations and DNA recovery

  • Laboratory research and genetic profiling

  • Clinical diagnostics