Build a Device History Record

How to Build a Device History Record with TofuPilot

The Device History Record (DHR) is a mandatory document for FDA-regulated medical devices. It's the complete production record for each finished device: what was built, how it was tested, and what the results were. TofuPilot provides the test data component of the DHR automatically.

What the FDA Requires

21 CFR 820.184 (Device History Record) requires documentation of:

DHR component	What it includes	TofuPilot's role
Production dates	When the device was manufactured	Test run timestamps
Quantity manufactured	How many in the lot/batch	Run count by batch
Acceptance records	Test results showing conformity	All measurements with limits
Primary identification label	Serial number, UDI	Unit under test serial
Labeling	Labels used on the device	(Outside TofuPilot scope)
Equipment used	Test stations, calibration status	Station identification

Test Data as DHR Evidence

Every test run in TofuPilot is a DHR evidence record. For each device serial number, TofuPilot stores:

dhr_test_record.py

from tofupilot import TofuPilotClient

client = TofuPilotClient()

# ICT (In-Circuit Test)
client.create_run(
    procedure_id="ICT-MEDICAL-BOARD",
    unit_under_test={
        "serial_number": "MD-2025-00421",
        "part_number": "CARDIAC-MONITOR-PCB-R5",
    },
    run_passed=True,
    steps=[{
        "name": "Component Verification",
        "step_type": "measurement",
        "status": True,
        "measurements": [
            {"name": "r1_resistance_kohm", "value": 10.02, "unit": "kohm", "limit_low": 9.5, "limit_high": 10.5},
            {"name": "c1_capacitance_uf", "value": 4.72, "unit": "uF", "limit_low": 4.23, "limit_high": 5.17},
            {"name": "u1_continuity", "value": 1, "unit": "bool", "limit_low": 1},
        ],
    }],
)

# Functional test
client.create_run(
    procedure_id="FUNC-CARDIAC-MONITOR",
    unit_under_test={"serial_number": "MD-2025-00421"},
    run_passed=True,
    steps=[{
        "name": "ECG Signal Chain",
        "step_type": "measurement",
        "status": True,
        "measurements": [
            {"name": "ecg_gain_db", "value": 60.2, "unit": "dB", "limit_low": 59.0, "limit_high": 61.0},
            {"name": "ecg_cmrr_db", "value": 112, "unit": "dB", "limit_low": 100},
            {"name": "ecg_noise_uv_rms", "value": 8.3, "unit": "uV", "limit_high": 15},
        ],
    }],
)

# Electrical safety
client.create_run(
    procedure_id="SAFETY-IEC60601",
    unit_under_test={"serial_number": "MD-2025-00421"},
    run_passed=True,
    steps=[{
        "name": "Patient Leakage",
        "step_type": "measurement",
        "status": True,
        "measurements": [
            {"name": "patient_leakage_normal_ua", "value": 4.2, "unit": "uA", "limit_high": 10},
            {"name": "patient_leakage_sfc_ua", "value": 22.1, "unit": "uA", "limit_high": 50},
        ],
    }],
)

# Final inspection
client.create_run(
    procedure_id="FINAL-INSPECTION",
    unit_under_test={"serial_number": "MD-2025-00421"},
    run_passed=True,
    steps=[{
        "name": "Cosmetic and Label Check",
        "step_type": "measurement",
        "status": True,
        "measurements": [
            {"name": "label_present", "value": 1, "unit": "bool", "limit_low": 1},
            {"name": "cosmetic_pass", "value": 1, "unit": "bool", "limit_low": 1},
            {"name": "udi_barcode_readable", "value": 1, "unit": "bool", "limit_low": 1},
        ],
    }],
)

Compiling the DHR

Search by serial number in TofuPilot to retrieve all test records for a device.

For device MD-2025-00421, the DHR test section shows:

Test	Date	Result	Station
ICT-MEDICAL-BOARD	2025-03-15 09:22	PASS	STN-ICT-02
FUNC-CARDIAC-MONITOR	2025-03-15 10:15	PASS	STN-FUNC-01
SAFETY-IEC60601	2025-03-15 11:30	PASS	STN-SAFETY-01
FINAL-INSPECTION	2025-03-15 14:00	PASS	STN-FINAL-01

Each row links to the complete measurement data: every value, every limit, every pass/fail status.

Handling Nonconformities in the DHR

When a device fails a test and is reworked, the DHR must show:

The original failure (which measurement, what value)
The disposition decision (rework, scrap, use-as-is)
The retest result after rework

TofuPilot captures #1 and #3 automatically. For #2, document the disposition in your QMS and cross-reference the TofuPilot run ID.

dhr_retest.py

# Original test failed
# Run ID: run-001 (patient leakage at 12.3 uA, limit 10 uA)

# After rework (replaced connector), retest
client.create_run(
    procedure_id="SAFETY-IEC60601-RETEST",
    unit_under_test={"serial_number": "MD-2025-00421"},
    run_passed=True,
    steps=[{
        "name": "Patient Leakage (Post-Rework)",
        "step_type": "measurement",
        "status": True,
        "measurements": [
            {"name": "patient_leakage_normal_ua", "value": 3.8, "unit": "uA", "limit_high": 10},
        ],
    }],
)

The DHR for this device now shows: original fail, rework disposition (from QMS), and passing retest.

Batch DHR Reports

For batch release, pull all devices in a production lot and verify complete test records.

batch_dhr_check.py

from tofupilot import TofuPilotClient

client = TofuPilotClient()

# Required procedures for a complete DHR
required_procedures = [
    "ICT-MEDICAL-BOARD",
    "FUNC-CARDIAC-MONITOR",
    "SAFETY-IEC60601",
    "FINAL-INSPECTION",
]

# Check all devices in the batch
batch_serials = [f"MD-2025-{i:05d}" for i in range(400, 450)]

incomplete = []
for serial in batch_serials:
    runs = client.get_runs(unit_serial=serial)
    completed_procedures = {r["procedure_id"] for r in runs if r["run_passed"]}
    missing = set(required_procedures) - completed_procedures
    if missing:
        incomplete.append({"serial": serial, "missing": missing})

if incomplete:
    print(f"{len(incomplete)} devices have incomplete DHRs:")
    for d in incomplete:
        print(f"  {d['serial']}: missing {d['missing']}")
else:
    print("All devices have complete DHRs. Batch ready for release.")

Retention and Retrieval

FDA requires DHR retention for the lifetime of the device plus additional years. TofuPilot stores all test data with timestamps and audit trails. Configure your data retention policy to match your regulatory requirements.

When FDA asks for a specific device's DHR during an inspection, search by serial number and export the complete test history. Structured, timestamped, immutable records replace paper binders and Excel files.

Integration with Your QMS

TofuPilot handles the test data component of the DHR. Your QMS (quality management system) handles:

Bill of materials and component traceability
Manufacturing work orders
Rework and disposition records
Labeling and packaging records
Release and distribution records

Together, TofuPilot and your QMS provide the complete DHR. The key is using consistent serial numbers across both systems so records can be cross-referenced.