IVD 仪器的安全与 EMC 考察点

结论：不接触患者，但样本是生物危害，测量准确性是核心

体外诊断仪器与其他医用电气设备的一个基本差别是：它不直接接触患者。 所以与患者相关的漏电流、应用部分分型这些要求，多数不适用。

但它有自己的特点：

处理的是生物样本。 血液、体液、组织，这些是潜在的生物危害，仪器的设计要防止操作者暴露和环境污染。

操作者是实验室人员。 使用环境是实验室而非临床，操作者是经过培训的技术人员，这影响某些安全要求的判定。

核心功能是测量。 测量结果的准确性是仪器的基本性能，而不是「设备能运转」。

所以适用的要求以实验室设备的安全要求为主，加上与测量准确性相关的性能考察。

适用要求的差异

「操作者防护」在 IVD 仪器上是重点，因为实验室人员每天接触大量样本，暴露风险来自样本而非设备本身。

机械安全的考察

IVD 仪器通常有较多的运动部件——机械臂、传送带、旋转盘、加样针。

运动部件的防护。 防止操作者接触运动部件，通常通过外壳、联锁门实现。

联锁的可靠性。 打开门时运动应当停止，联锁不应易被旁路。

夹持与挤压。 运动部件之间的间隙评价。

锐利部分。 加样针等锐器的防护。

稳定性。 仪器在台面或地面上的稳定性，特别是有运动部件时的振动。

搬运。 重型仪器的搬运安全。

「联锁不应易被旁路」值得注意。 实际中操作者为了观察或排故可能旁路联锁，设计上应当增加旁路的难度，或者在旁路状态下限制运动速度。

生物安全的考察

气溶胶的防护。 加样、混匀、离心过程可能产生气溶胶。

样本溢出的处理。 溢出后的收集和清洁。

废液与废料。 收集、容器、更换时的防护。

表面的可消毒性。 外表面和易污染部位的材料耐消毒。

内部污染的清洁。 液路和内部空间的清洁可及性。

交叉污染的防止。 样本之间的交叉污染，影响结果准确性也涉及生物安全。

「交叉污染」在 IVD 仪器上既是生物安全问题也是性能问题，因为携带污染会导致假阳性结果。这一项应当专门验证。

电气安全的考察

基本项目。 漏电流（对地、对外壳）、耐压、接地、温升、单一故障。

液体环境。 仪器内部有液路，液体泄漏到电气部分的风险要考虑。防护设计和泄漏检测。

高温部件。 反应模块的加热、干燥单元的发热。

紫外光源。 某些仪器含紫外光源，涉及辐射防护。

激光。 含激光的仪器涉及激光安全。

「液体泄漏到电气部分」是 IVD 仪器的特有风险，因为液路和电路在同一机箱内。应当验证液体泄漏时的安全，以及是否有泄漏检测。

电磁兼容的关注点

发射。 与一般设备类似，但 IVD 仪器功率可能较大（加热、离心）。

抗扰度的判定。 关键在基本性能的定义。

基本性能。 对 IVD 仪器，测量结果的准确性是基本性能的核心。

干扰下的失效模式。 仪器可能不停机但测量结果已经偏移，这是最危险的失效模式，因为使用者拿到的是错误但看起来正常的结果。

监测方法。 抗扰度测试中如何判断测量准确性——通常需要在施加干扰的同时进行标准品的测量。

「不停机但结果偏移」是 IVD 仪器抗扰度测试的重点。 判定准则应当明确：干扰期间测量值的允许偏差是多少，超过就是失效。

基本性能的定义

建议包含：

测量结果的准确性。 在干扰下测量值与真值的偏差不超过规定范围。

结果的可靠标识。 如果结果不可靠，仪器应当标识或拒绝报告，而不是给出看似正常的结果。

样本与结果的对应。 不发生样本混淆。

数据完整性。 结果不被破坏或丢失。

安全功能。 联锁、急停的有效性。

「结果不可靠时的标识」是有价值的设计。 仪器如果能检测到异常并标记结果，比静默给出偏移的结果安全得多。

送检准备的建议

提供配套试剂与标准品。 抗扰度测试中需要实际测量。

说明测量原理与关键参数。 便于确定监测方法。

提供基本性能定义与允许偏差。

说明样本处理流程。 涉及生物安全的评价。

准备样本模拟物。 测试中不宜用真实生物样本。

说明废液与废料的处理。

「样本模拟物」应当能代表实际样本的物理特性（粘度、表面张力），这样加样精度和流路的测试才有代表性。

软件与数据

IVD 仪器的软件承担关键功能，相关考察包括：

结果计算。 从原始信号到报告结果的计算逻辑。

校准与质控。 校准曲线的建立、质控规则的实现。

样本追踪。 样本标识与结果的对应，防止混淆。

数据管理。 结果的存储、查询、导出、与信息系统的对接。

权限管理。 不同角色的操作权限。

审计追踪。 关键操作和数据修改的记录。

「样本追踪」是安全相关的功能，样本混淆意味着患者拿到别人的结果，后果严重。这一项应当在验证中专门覆盖。

使用与维护

资料中应当包含：安装与环境要求；日常操作流程；校准与质控的要求与频次；日常维护与清洁；生物安全相关的操作规程；废液废料的处理；以及故障处理。

「生物安全操作规程」应当具体，包括溅洒处理、废液更换、以及个人防护的要求。

我们的做法

承接 IVD 仪器委托时，我们会先与委托方确认基本性能的定义和允许偏差，因为抗扰度测试的判定完全依赖这一条。 如果只定义为「仪器正常运转」，测量结果偏移就无法判定为失效。

测试方法上，我们建议在施加干扰的同时进行标准品测量，这样能直接判断测量准确性是否受影响，而不是只看仪器有没有报错。

如果你有 IVD 仪器需要安排检测，想先理清项目和基本性能的定义，可以把产品资料发过来一起讨论，或者直接联系：132 4819 8029。能力范围见服务介绍，送检要求见送检要求，流程见检测流程。

English version

Conclusion. In vitro diagnostic instruments differ fundamentally from other medical electrical equipment in one respect: they do not contact the patient. Patient leakage current and applied part classification therefore mostly do not apply. They have their own characteristics, however. They handle biological samples, whether blood, body fluids or tissue, which are potential biohazards, so the design must prevent operator exposure and environmental contamination. Their operators are laboratory staff, working in a laboratory rather than a clinical setting, which affects how certain safety requirements are judged. And their core function is measurement, so accuracy of results is the essential performance rather than simply that the instrument runs. Applicable requirements therefore centre on laboratory equipment safety, plus performance examination relating to measurement accuracy.

Differences in applicable requirements. Patient leakage current applies to general medical electrical equipment and usually not to diagnostic instruments. Applied part classification is required for the former and usually absent in the latter. Biological safety depends on the product for the former and is a principal requirement for the latter. Mechanical safety applies to both, with diagnostic instruments having many moving parts. Operator protection is a general requirement for the former and a principal one for the latter. And essential performance relates to therapy and monitoring for the former and to measurement accuracy for the latter. Operator protection is a focus for diagnostic instruments because laboratory staff handle large numbers of samples daily and the exposure risk comes from the samples rather than the instrument.

Mechanical safety. Diagnostic instruments typically contain many moving parts: robotic arms, conveyors, rotating carousels and sampling probes. Guarding must prevent operator contact with moving parts, usually through enclosures and interlocked doors. Interlock reliability requires that movement stops when a door opens and that the interlock cannot easily be defeated. Entrapment and crushing require gap assessment between moving parts. Sharps such as sampling probes require protection. Stability covers the instrument on bench or floor, particularly against vibration from moving parts. And handling covers safe movement of heavy instruments. Interlock defeat deserves attention: operators may bypass interlocks to observe or troubleshoot, and the design should make bypassing difficult or limit movement speed when bypassed.

Biological safety. Aerosol protection addresses aerosols generated by pipetting, mixing and centrifugation. Spill handling covers containment and cleaning. Waste liquid and solid waste cover collection, containers and protection during replacement. Surface disinfectability covers material tolerance on external surfaces and contamination-prone areas. Internal cleaning covers accessibility of fluid paths and internal spaces. And cross-contamination prevention addresses carryover between samples, which affects both accuracy and biological safety. Cross-contamination is both a safety and a performance matter for diagnostic instruments, since carryover produces false positive results, and it warrants specific verification.

Electrical safety. Basic items cover leakage current to earth and enclosure, dielectric strength, earthing, temperature rise and single fault conditions. The liquid environment matters, since fluid paths run inside and leakage onto electrical sections is a risk requiring protective design and leak detection. Hot components include reaction module heating and drying units. Ultraviolet sources in some instruments raise radiation protection questions. And lasers in some instruments raise laser safety questions. Fluid leakage onto electrical sections is the risk specific to diagnostic instruments, since fluid paths and circuits share an enclosure. Verify safety under leakage and whether leak detection exists.

Electromagnetic compatibility. Emissions resemble general equipment, though diagnostic instruments may draw substantial power for heating and centrifugation. Immunity judgement depends critically on the essential performance definition. Essential performance for a diagnostic instrument centres on measurement accuracy. The failure mode under disturbance matters: the instrument may continue running while its results have already shifted, which is the most dangerous mode because the user receives a wrong result that appears normal. And monitoring methods must establish how accuracy is judged during immunity testing, which usually requires measuring standards while disturbance is applied. Running without stopping while results shift is the focus of immunity testing for these instruments, and the acceptance criteria must state the permitted deviation during disturbance, beyond which it is a failure.

Defining essential performance. It should include measurement accuracy, with deviation from true values under disturbance within a stated range; reliable flagging of results, so that unreliable results are flagged or withheld rather than reported as apparently normal; correspondence between sample and result, with no sample mix-up; data integrity, with results neither corrupted nor lost; and safety functions, with interlocks and emergency stop effective. Flagging unreliable results is a valuable design feature: an instrument able to detect an abnormality and mark the result is considerably safer than one silently reporting a shifted value.

Preparing for submission. Provide the accompanying reagents and standards, since immunity testing requires actual measurement. Describe the measurement principle and key parameters to establish monitoring methods. Provide the essential performance definition and permitted deviation. Describe the sample handling workflow for biological safety assessment. Prepare sample simulants, since real biological samples should not be used in testing. And describe waste liquid and solid waste handling. Sample simulants should represent the physical characteristics of real samples in viscosity and surface tension, so that pipetting accuracy and fluid path testing are representative.

How we handle it. For diagnostic instruments we agree the essential performance definition and permitted deviation with the client first, since immunity judgement depends entirely on it. Defined merely as the instrument operating normally, a shift in measured results cannot be judged a failure. On method we suggest measuring standards while disturbance is applied, which judges measurement accuracy directly rather than relying on whether the instrument reports an error.

Send us the product documentation and we will work through the items and the essential performance definition. Phone or WeChat: +86 132 4819 8029.