Comparing SPII vs PHI and PII: A Sensitive Information Guide

Sensitive information has never been more vulnerable, or more misunderstood. As data moves across clouds, SaaS platforms, and now into GenAI assistants like Copilot and ChatGPT, organizations are realizing that not all “personal data” is created equal.

You’ve probably heard terms like PII, PHI, and SPII, and maybe you’ve used them interchangeably. However, they relate to very different categories of information, and confusing them could lead to compliance problems, misclassified data, and sensitive data being leaked to GenAI.

This guide breaks down each category, shows where they overlap, and explains why understanding those differences matters for protecting your company’s most sensitive assets.

Why These Definitions Matter More Than Ever

A decade ago, these data categories mostly resided in compliance manuals: PII under the GDPR and CCPA, PHI under HIPAA, and so on. But with the explosion of GenAI, sensitive data isn’t sitting quietly and motionless in databases anymore. It’s being pasted into prompts, summarized by assistants, and stored in logs that security teams rarely see.

That shift means data classification is no longer a checkbox exercise, but an active, ongoing defense strategy. CISOs and compliance teams need to know exactly what type of sensitive data is being used, where it’s stored, and who (or what GenAI tool) has access to it.

Modern data security governance platforms can automate this process. They utilize context-aware intelligence to classify SPII, PHI, and PII across all repositories and GenAI interactions, enabling you to detect risks well before data leaves your control.

Defining PII, PHI, and SPII

Once upon a time, sensitive data fit neatly into categories. PII meant personal info, PHI meant health data, and SPII meant the really private stuff. However, with GenAI assistants now handling emails, reports, and code, those lines have begun to blur. 

Let’s break down what each type actually means and why keeping them straight has never been more important.

What is PII (Personally Identifiable Information)?

PII refers to any data that can identify an individual, directly or indirectly. Think names, email addresses, phone numbers, IP addresses, or government IDs. PII is governed by privacy laws like GDPR, CCPA, and LGPD.

While most organizations have policies around PII, GenAI tools are remixing the risk landscape. When employees upload reports or prompt Copilot to “summarize all client files,” those files often contain PII that may be exposed to AI model memory or logs.

The takeaway is this: PII might seem harmless on its own, but when combined with other data points or shared through GenAI workflows, it can easily cross into SPII or PHI territory.

What is PHI (Protected Health Information)?

PHI is any health-related data tied to an identifiable person. Under HIPAA, this includes medical histories, laboratory results, insurance claims, and appointment records.

Today’s risk is that healthcare teams and HR departments are increasingly relying on GenAI to generate summaries, track wellness programs, or process claims. If that GenAI assistant has access to PHI—especially outside HIPAA-compliant systems—the organization faces regulatory and reputational exposure.

Example: A GenAI tool summarizing a spreadsheet of patient test results might store that information in its history. Without oversight, that data can resurface in unrelated queries.

What is SPII (Sensitive Personally Identifiable Information)?

SPII takes PII a step further. It includes information that could cause serious harm if disclosed, such as Social Security numbers, passport details, financial account numbers, or biometric data.

This category is recognized by frameworks like NIST SP 800-122 and U.S. federal privacy laws. Breaches involving SPII often trigger strict notification requirements and carry the heaviest penalties.

When it comes to GenAI, SPII can be exposed in subtle ways. In one example, an employee may paste a payroll record into ChatGPT or share tax information through a GenAI-driven workflow.

In short, SPII = PII, which can do real damage if mishandled.

SPII vs PHI vs PII: A Quick Comparison

Where PII, PHI and SPII Overlap

PII, PHI, and SPII aren’t isolated boxes, as they do overlap. Every piece of PHI, for example, is also PII. And much of SPII, like a driver’s license number, can qualify as PII (or even PHI) if used in a medical record.

Here’s where things get messy in practice:

• HR teams may store vaccination records (PHI) in employee files (PII).
• Finance departments process payroll forms that contain both Social Security numbers (SPII) and addresses (PII).
• Marketing teams utilize GenAI to craft personalized outreach, often combining multiple data types without being aware of it.

Without precise (and context-aware) classification and continuous monitoring, those overlaps make it easy for sensitive information to spread unnoticed across SaaS tools and GenAI integrations.

How GenAI Changes the Risk Equation

Traditional DLP tools look for patterns such as credit card numbers, SSNs, or regular expression (regex) matches. But GenAI rewrites that script with a huge red marker.

GenAI tools not only process data, but they also understand it, remember it, and can accidentally reuse it.

For example:

• A Copilot instance trained on shared drives might inadvertently learn sensitive customer data.
• A ChatGPT Enterprise account could summarize internal documents containing PHI, and parts of that data could reappear in later prompts.
• GenAI-generated drafts can embed fragments of SPII or PHI that evade legacy scanners.

This is why classification alone isn’t enough. You need context: what the data means, where it lives, and how it’s being used.

That’s where Concentric AI shines: identifying sensitive content through semantic understanding, automatically applying risk policies, and preventing accidental exposure in GenAI environments.

How Concentric AI Protects SPII, PHI, and PII

Concentric AI’s Semantic Intelligence™ platform discovers, classifies, and protects sensitive data wherever it lives across the enterprise—structured or unstructured, cloud or on-prem.

Semantic Intelligence’s key capabilities include:

• Classification with context: Automatically identifies PII, PHI, and SPII—even in unstructured documents, chat logs, and GenAI-generated files.
• GenAI-Aware risk detection: Flags sensitive data embedded in prompts, training datasets, or AI summaries.
• Access governance: Detects oversharing, misconfigured permissions, and GenAI integrations that increase exposure.
• Automated remediation: Supports deletion, archiving, masking, or blocking data to meet regulatory and organizational standards.

Concentric AI’s approach goes well beyond discovery, providing the continuous governance needed to keep data safe in a GenAI-driven workplace.

Key Takeaways

• PII identifies individuals. SPII is a high-risk subset of PII. PHI covers identifiable health information under HIPAA.
• GenAI blurs these distinctions by moving sensitive data across systems faster than traditional security can track.
• Visibility and context are essential. You can’t protect what you can’t see (or what your GenAI assistants are quietly remembering.)
• Semantic Intelligence leverages intelligent classification and continuous monitoring to safeguard sensitive data, ensure compliance, and prevent it from falling into GenAI risk zones.