Sample Storage PCB: Compliant Design for Medical Sample Integrity and Traceability

technologySeptember 29, 2025 12 min read

Sample Storage PCBBlood Gas Analyzer PCBDigital Microscope PCBSpectrophotometer PCBLiquid Handling PCBHematology Analyzer PCB

In modern clinical diagnostics and life science research, sample integrity is the cornerstone of the accuracy of all subsequent analyses and diagnostic results. As the core control unit of automated sample storage systems, the reliability and compliance of Sample Storage PCB design and manufacturing directly relate to patient safety and the effectiveness of diagnosis. It is not just a circuit board; it is crucial for ensuring the stable preservation of biological samples (such as blood, tissue, DNA) under specified conditions (e.g., ultra-low temperature, constant humidity) and for achieving accurate data traceability. From a regulatory perspective, any minor design flaw could lead to sample invalidation, data loss, or even erroneous clinical decisions, with unimaginable consequences. Therefore, we must examine and develop Sample Storage PCB to the highest standards of medical devices.

This article, from the perspective of a medical device regulatory expert, will delve into the core regulatory requirements, risk management strategies, and technical implementation paths that Sample Storage PCB must follow during its design, development, and verification process, ensuring its compliance with the stringent standards of IEC 60601, ISO 13485, and FDA/CE/NMPA.

Core Functions and Regulatory Classification of Sample Storage PCB

The primary responsibility of Sample Storage PCB is to precisely control and monitor the sample storage environment and record all relevant data. Its core functions typically include:

Environmental Control: Precisely maintaining set temperature and humidity by driving refrigeration compressors, heating elements, and humidity controllers.
Status Monitoring: Real-time monitoring of environmental parameters within the storage chamber using high-precision sensors (e.g., platinum resistance thermometers, thermocouples).
Data Recording and Traceability: Continuously recording historical temperature and humidity data, door open events, and alarm logs, ensuring data immutability and compliance with Data Integrity requirements.
Alarm System: Issuing alarms via sound, light, network, etc., when environmental parameters deviate from the preset range, power is interrupted, or hardware fails.
User Interface and Communication: Communicating with a host computer or central monitoring system to upload data and receive commands.

Based on its intended use and potential risks, medical sample storage devices equipped with Sample Storage PCB are typically classified as Class II medical devices (FDA Class II) or Class IIa/IIb medical devices (CE MDR Class IIa/IIb). This means their design and manufacturing must be conducted under a strict quality management system and require corresponding pre-market approval or certification. For instance, storage systems used for long-term preservation of transplant organs or critical samples for in vitro diagnostics (IVD) would have a higher risk level.

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Design Control and Documentation in Accordance with ISO 13485

ISO 13485:2016 is the gold standard for Quality Management Systems (QMS) in the medical device industry. For the development of Sample Storage PCB, Design Controls are central to the entire process. It requires manufacturers to establish a systematic process to ensure that every stage of the product, from concept to mass production, is thoroughly verified and validated. Design control processes apply not only to final devices but also entirely to critical components like the Sample Storage PCB. Every design decision, from the selection of the microcontroller to the layout of the power circuit, must be documented and form a complete “Design History File” (DHF). This is equally critical for devices with extremely high real-time requirements, such as the Blood Gas Analyzer PCB, where design documentation must be impeccable.

Design Control Gates

According to ISO 13485, the development of the Sample Storage PCB must undergo a series of strict phased reviews to ensure design quality and compliance.

Phase	Core Task	Key Output Documents
Design Input (Input)	Define user requirements, performance metrics, regulatory standards (e.g., temperature range, accuracy, alarm response time, IEC 60601-1 requirements).	Design and Development Plan, User Requirements Specification (URS), Product Requirements Specification (PRS).
Design Output (Output)	Translate inputs into specific design solutions. Includes schematics, PCB layout, Bill of Materials (BOM), software source code.	Schematics, Gerber files, BOM, Firmware code.

Design Verification (Verification) Confirm that the design output meets the design input requirements. "Did we build the product correctly?" Unit test reports, code review records, electrical performance test reports, EMC pre-test reports. Design Validation (Validation) Test on the final product or equivalent to confirm that the product meets user needs and intended use. "Did we build the correct product?" System-level test reports, environmental test reports, usability evaluation reports. Design Transfer (Transfer) Seamlessly transfer the verified design solution to the manufacturing process. Standard Operating Procedures (SOP), Standard Inspection Procedures (SIP), Equipment Maintenance Plan.

IEC 60601-1 Electrical Safety: Protecting Operators and Samples

Although sample storage devices typically do not directly contact patients, as electrical equipment used in a medical environment, their Sample Storage PCB must strictly comply with the IEC 60601-1 standard to ensure the safety of operators (doctors, nurses, technicians).

Key considerations include:

Means of Operator Protection (MOOP): The power supply section on the PCB must provide adequate insulation protection. This includes the insulation class of transformers, the selection of optocouplers, and compliant design for creepage distances and electrical clearances. Typically, 2 x MOOP requirements need to be met.
Leakage Current: Enclosure leakage current and earth leakage current must be strictly controlled under normal and single fault conditions to prevent electric shock risk to operators.
Fire and Overheating Protection: PCB design must consider component power consumption and heat dissipation. For high-power devices, such as compressor drive circuits, multilayer PCB design is required, along with heatsinks or fans. Additionally, overcurrent protection (fuses, PTC) and overtemperature protection mechanisms must be in place.

IEC 60601-1 Key Electrical Safety Requirements Checklist

For the Sample Storage PCB design, the following safety requirements must be checked item by item:

✓ Insulation Coordination: Do creepage distances and air clearances comply with operating voltage and pollution degree requirements?
✓ Dielectric Strength Test: Can the isolation barrier on the PCB withstand the specified high-voltage test?
✓ Protective Earth: Is the impedance of the earth path sufficiently low (typically < 0.1Ω)?
✓ Component Selection: Do all critical components (e.g., power supplies, fuses, connectors) have the corresponding safety certifications?
✓ Temperature Rise Test: Are the temperatures of all components and PCB traces within safe limits under maximum load?

ISO 14971 Risk Management: Eliminating Hazards from the Design Source

Risk management is the core soul of medical device development. For the Sample Storage PCB, we must systematically identify, evaluate, and control all foreseeable risks. ISO 14971 provides a complete framework for carrying out this process.

Key risk sources include:

Temperature control failure: May be caused by sensor failure, MCU crash, or damage to the drive circuit. The consequence is the total or partial invalidation of samples, causing immeasurable scientific research or clinical losses.
Data logging interruption or error: May be caused by damaged storage chips, firmware bugs, or power fluctuations. The consequence is the inability to trace sample history, failing to comply with GxP (Good Practice) requirements.
Alarm system failure: Fails to notify users in time when an anomaly occurs, delaying remedial measures.
Electrical hazards: As mentioned earlier, may cause operator electric shock or equipment fire.

For these risks, control measures must be taken at the design stage. For example, to address temperature control failure, redundant temperature sensors, watchdog circuits to monitor MCU status, and independent hardware over-temperature protection circuits can be used. These complex control logics are also common in precise Digital Microscope PCB designs to ensure the stability of image acquisition.

ISO 14971 Risk Management Process

A closed-loop risk management process to ensure risks are reduced to an acceptable level (ALARP) throughout the product's entire lifecycle.

1. Risk Analysis
(Hazard identification, Risk assessment)

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2. Risk Evaluation
(Is the risk acceptable?)

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3. Risk Control
(Inherently safe design, Protective measures, Safety information)

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4. Evaluation of Overall Residual Risk
(Is the overall risk acceptable?)

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5. Risk Management Report
(Record all activities)

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6. Post-Production Information
(Continuous monitoring)

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IEC 62304 Software Life Cycle: Ensuring Data Integrity and Cybersecurity

Firmware on the Sample Storage PCB is considered medical device software. Therefore, its development must follow the IEC 62304 standard. This standard categorizes software into three safety classes: A, B, and C, based on the severity of harm that software failure might cause. For sample storage devices, the software is typically classified as Class B (potentially leading to non-serious injury) or Class C (potentially leading to death or serious injury), as data loss or errors could lead to incorrect diagnoses.

Key requirements of IEC 62304 include:

Software Development Plan: Before coding, the entire development process, resources, and methods must be planned.
Software Requirements Analysis: Clearly define all functions, performance, and interfaces that the software needs to implement.
Software Architecture Design: Design a modular software architecture that is easy to test and maintain. This is especially crucial for complex systems, such as the Liquid Handling PCB, where motion control and sensor fusion software must have a clear architecture.
Software Unit Verification and Integration Testing: Independently test each software module, then perform integration testing to ensure normal collaboration between modules.
Software System Testing: Verify that the software meets all requirements on the final hardware.
Software Risk Management: Identify software-related risks (e.g., logical errors, memory overflow, timing issues) and implement mitigation measures.

Furthermore, with the networking of medical devices, cybersecurity has become an indispensable aspect. The Sample Storage PCB must be protected from unauthorized access, ensuring data confidentiality and integrity during transmission and storage.

Electromagnetic Compatibility (EMC) and Verification & Validation (V&V) Testing

The medical environment is filled with various electronic devices, and electromagnetic interference is ubiquitous. The Sample Storage PCB must comply with the IEC 60601-1-2 standard, ensuring its stable operation in complex electromagnetic environments without interfering with other devices (such as the adjacent Hematology Analyzer PCB).

Key EMC design points include:

Power Supply Filtering: Design effective EMI filters at the power input.
PCB Layout: Reasonable layout and routing, such as separating digital and analog grounds, shielding sensitive signal lines, terminating clock signals, etc. Adopting High-Density Interconnect (HDI) PCB technology can better control signal integrity and EMC performance.
Enclosure Shielding: Uses a metal enclosure to provide good electromagnetic shielding.

After completing the design, comprehensive Verification and Validation (V&V) testing is the only way to prove product safety, effectiveness, and compliance. This is not just functional testing, but a systematic engineering activity.

Sample Storage PCB Verification and Validation (V&V) Test Plan

The V&V plan is a critical component of the Design History File (DHF), defining how to demonstrate that the product meets all requirements.

Test Category	Example Test Items	Standard/Document Reference
Electrical Safety Tests	- Dielectric Strength (Hipot) - Leakage Current Test - Ground Continuity	IEC 60601-1
EMC Tests	- Radiated Emissions (RE) - Conducted Emissions (CE) - Electrostatic Discharge (ESD) Immunity - Radio Frequency (RF) Immunity	IEC 60601-1-2
Performance and Functional Tests		- Temperature control accuracy and uniformity - Alarm function verification - Data logging and recovery test	Product Requirements Specification (PRS)
Environmental and Reliability Testing	- High/low temperature cycling/storage - Damp heat test - Vibration and shock testing - Highly Accelerated Life Test (HALT)	IEC 60068 Series
Software Verification	- Unit/Integration/System Testing - Static/Dynamic Code Analysis - Boundary condition and exception handling testing	IEC 62304

Choosing an experienced one-stop PCBA service provider can greatly simplify the V&V process, as they can provide comprehensive support from manufacturing to testing.

Conclusion

In summary, the design and development of Sample Storage PCB is a highly complex system engineering task, requiring engineers to possess not only profound knowledge of electronic technology but also a comprehensive and deep understanding of medical device regulations. From initial requirements definition to final product launch, patient safety and regulatory compliance must be prioritized at every stage. By strictly adhering to ISO 13485 design control processes, implementing ISO 14971 risk management, meeting IEC 60601-1 electrical safety requirements, and following IEC 62304 software development guidelines, we can create a truly reliable, safe, and compliant Sample Storage PCB. Whether for sample preparation in Spectrophotometer PCB or for calibration material storage in Blood Gas Analyzer PCB, a high-quality Sample Storage PCB is a crucial guarantee for ensuring the accuracy of the entire diagnostic process.