The Patient Safety Triad: Medications, Allergies, and Immunizations

Purpose: To master Epic’s approach to three safety-critical datasets that work together to prevent adverse events: what medications a patient is on, what they are allergic to, and what protections they have from immunizations.

The Foundation of Patient Safety

These three clinical domains form the foundation of preventive care and clinical decision support. Medications must be checked against allergies to prevent adverse reactions, and immunizations are tracked to prevent disease. Together, they create a safety net for every patient.

Overview of safety-critical data volumes

View SQL Query

SELECT 
    'Medication Orders' as data_type, COUNT(*) as records FROM ORDER_MED
UNION ALL
SELECT 'Allergies', COUNT(*) FROM PAT_ALLERGIES
UNION ALL
SELECT 'Immunizations', COUNT(*) FROM PAT_IMMUNIZATIONS
ORDER BY records DESC;

data_type	records
Immunizations	16
Allergies	5
Medication Orders	4

1. Medications: The Prescription Trail

Medication management starts with an order in ORDER_MED and follows a complex lifecycle from prescription to pharmacy and potentially to discontinuation.

View current medication orders with status

View SQL Query

SELECT 
    ORDER_MED_ID,
    DESCRIPTION as Medication,
    ORDER_STATUS_C_NAME as Status,
    SUBSTR(ORDERING_DATE, 1, 10) as Order_Date,
    QUANTITY,
    REFILLS
FROM ORDER_MED
WHERE PAT_ID = 'Z7004242'
  AND ORDER_STATUS_C_NAME IN ('Sent', 'Active')
ORDER BY ORDERING_DATE DESC
LIMIT 10;

ORDER_MED_ID	Medication	Status	Order_Date	QUANTITY	REFILLS
772179261	LISINOPRIL 10 MG PO TABS	Sent	8/29/2022	90 tablet	1
772179269	NORTRIPTYLINE HCL 10 MG PO CAPS	Sent	2/20/2023	180 capsule	3
945468373	NORTRIPTYLINE HCL 10 MG PO CAPS	Sent	12/22/2023	270 capsule	3
772179266	NORTRIPTYLINE HCL 10 MG PO CAPS	Sent	12/1/2022	90 capsule	1

The patient’s instructions, or “sig,” are stored in a separate table.

Get patient sig instructions for a medication

View SQL Query

SELECT 
    om.DESCRIPTION as Medication,
    oms.SIG_TEXT as Instructions
FROM ORDER_MED om
JOIN ORDER_MED_SIG oms ON om.ORDER_MED_ID = oms.ORDER_ID
WHERE om.PAT_ID = 'Z7004242'
ORDER BY om.ORDERING_DATE DESC
LIMIT 5;

Medication	Instructions
LISINOPRIL 10 MG PO TABS	Take 1 (one) tablet by mouth daily.
NORTRIPTYLINE HCL 10 MG PO CAPS	TAKE 1 CAPSULE BY MOUTH EVERY NIGHT. START WITH 1 CAPSULE AT NIGHT; CAN. INCREASE TO 2 CAPSULES AFTER 1-2 WEEKS IF NO SIDE EFFECTS
NORTRIPTYLINE HCL 10 MG PO CAPS	Take 3 (three) capsules by mouth nightly.
NORTRIPTYLINE HCL 10 MG PO CAPS	Take 1 (one) capsule by mouth nightly. Start with 10 mg at night; can increase to 20 mg after 1-2 weeks if no side effects

The Missing MAR: A critical point is the absence of Medication Administration Records (MAR) in this EHI export. We can see what was ordered, but we cannot verify what was administered.

2. Allergies: The Safety Net

Epic’s allergy model is robust, tracking not just allergens but also specific reactions and their severity.

View a patient's active allergies and their severity

View SQL Query

SELECT 
    a.ALLERGEN_ID_ALLERGEN_NAME,
    a.REACTION as Reaction,
    a.SEVERITY_C_NAME as Severity,
    SUBSTR(a.DATE_NOTED, 1, 10) as Date_Noted
FROM PAT_ALLERGIES pa
JOIN ALLERGY a ON pa.ALLERGY_RECORD_ID = a.ALLERGY_ID
WHERE pa.PAT_ID = 'Z7004242'
  AND a.ALRGY_STATUS_C_NAME = 'Active'
ORDER BY a.SEVERITY_C_NAME, a.ALLERGEN_ID_ALLERGEN_NAME;

ALLERGEN_ID_ALLERGEN_NAME	Reaction	Severity	Date_Noted
PEANUT (DIAGNOSTIC)		Allergy	7/14/2020
PENICILLINS		Allergy	8/9/2018 1
SULFA ANTIBIOTICS		Allergy	8/9/2018 1
TREE NUT		Allergy	8/9/2018 1

For each allergy, multiple specific reactions can be documented.

See detailed reactions for a specific allergy

View SQL Query

SELECT 
    a.ALLERGEN_ID_ALLERGEN_NAME,
    ar.REACTION_C_NAME as Specific_Reaction
FROM PAT_ALLERGIES pa
JOIN ALLERGY a ON pa.ALLERGY_RECORD_ID = a.ALLERGY_ID
JOIN ALLERGY_REACTIONS ar ON a.ALLERGY_ID = ar.ALLERGY_ID
WHERE pa.PAT_ID = 'Z7004242' AND UPPER(a.ALLERGEN_ID_ALLERGEN_NAME) LIKE '%PENICILLIN%'
ORDER BY a.ALLERGEN_ID_ALLERGEN_NAME, ar.LINE;

ALLERGEN_ID_ALLERGEN_NAME	Specific_Reaction
PENICILLINS	Hives

3. Immunizations: Proactive Protection

Immunization records track a patient’s vaccination history, including the vaccine, date, dose, and source.

View a patient's immunization history

View SQL Query

SELECT 
    i.IMMUNZATN_ID_NAME as Vaccine,
    SUBSTR(i.IMMUNE_DATE, 1, 10) as Date_Given,
    i.DOSE,
    i.ROUTE_C_NAME as Route
FROM PAT_IMMUNIZATIONS pi
JOIN IMMUNE i ON pi.IMMUNE_ID = i.IMMUNE_ID
WHERE pi.PAT_ID = 'Z7004242'
ORDER BY i.IMMUNE_DATE DESC;

Vaccine	Date_Given	DOSE	Route
INFLUENZA (FLUARIX) IIV4	9/28/2023	0.5 mL	Intramuscular
COVID-19 (PFIZER-BIVALENT) MRNA AGES 12+	9/25/2022		Intramuscular
COVID-19 (MODERNA) MRNA	5/16/2021		Intramuscular
COVID-19 (MODERNA) MRNA	4/18/2021		Intramuscular
TYPHOID INACTIVATED (TYPHIM VI)	2/5/2019 1		Intramuscular
TDAP	2/5/2019 1		Intramuscular
HEPATITIS A (HAVRIX) HEPA ADULT	2/5/2019 1		Intramuscular
COVID-19 (MODERNA) MRNA	12/3/2021		Intramuscular
INFLUENZA (FLUCELVAX) CCIIV4, PREFILLED SYRINGE	11/13/2019		Intramuscular
INFLUENZA, UNSPECIFIED FORMULATION	10/8/2018		Intramuscular
INFLUENZA, INACTIVATED, QUADRIVALENT, ALL AGES 6 MONTHS AND OLDER, SINGLE DOSE SYRINGE/VIAL	10/8/2018		Intramuscular
INFLUENZA, INACTIVATED, QUADRIVALENT, ALL AGES 6 MONTHS AND OLDER, SINGLE DOSE SYRINGE/VIAL	10/26/2022		Intramuscular
INFLUENZA (FLUCELVAX) CCIIV4, PREFILLED SYRINGE	10/25/2017		Intramuscular
INFLUENZA, INACTIVATED, QUADRIVALENT, ALL AGES 6 MONTHS AND OLDER, SINGLE DOSE SYRINGE/VIAL	10/24/2021		Intramuscular

Epic distinguishes between vaccines administered at the facility (Given) and those reported by the patient or another provider (Historical).

View complete vaccine administration details including lot number

View SQL Query

SELECT 
    IMMUNZATN_ID_NAME as vaccine,
    IMMUNE_DATE,
    MFG_C_NAME as manufacturer,
    LOT as lot_number,
    EXP_DATE as expiration
FROM IMMUNE
WHERE LOT IS NOT NULL
ORDER BY IMMUNE_DATE DESC
LIMIT 5;

vaccine	IMMUNE_DATE	manufacturer	lot_number	expiration
INFLUENZA (FLUARIX) IIV4	9/28/2023 12:00:00 AM	GLAXO SMITH KLINE	5ME77
COVID-19 (PFIZER-BIVALENT) MRNA AGES 12+	9/25/2022 12:00:00 AM
COVID-19 (MODERNA) MRNA	5/16/2021 12:00:00 AM
COVID-19 (MODERNA) MRNA	4/18/2021 12:00:00 AM
HEPATITIS A (HAVRIX) HEPA ADULT	2/5/2019 12:00:00 AM

Lot number tracking is crucial for safety recalls.

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Key Takeaways

• The Safety Triad: Medications (ORDER_MED), Allergies (PAT_ALLERGIES, ALLERGY), and Immunizations (PAT_IMMUNIZATIONS, IMMUNE) work together to ensure patient safety.
• Medication Lifecycle: ORDER_MED tracks prescriptions, but this EHI export lacks Medication Administration Records (MAR) to confirm if they were taken.
• Allergy Details: The allergy model captures not just the allergen but also specific reactions and severity, providing crucial detail for clinical decisions.
• Immunization Source: The IMMNZTN_STATUS_C_NAME field is vital for distinguishing between vaccines given on-site and historical records.
• Critical Missing Data: Key safety features like MAR, drug-drug interaction checks, and standardized CVX vaccine codes are not present in this EHI export.

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