Blood Donation, Collection, and Processing Vocabulary

Regulatory Guidelines and Donor Selection Overview

  • Regulatory Framework:
    • The Food and Drug Administration (FDA) establishes blood donor criteria through the Code of Federal Regulations.
    • Guidelines governing blood centers and transfusion practice are established in the Standards for Blood Banks and Transfusion Services published by the AABB (formerly the American Association of Blood Banks).
    • The AABB developed a standardized Donor History Questionnaire that meets all FDA requirements.
  • Core Stages of Donor Screening:
    • Registration: Documentation and verification of donor personal and historical data.
    • Health History: Comprehensive questionnaire and interview to screen for donor and recipient safety.
    • Physical Examination: Objective measurement of vital signs and hematologic parameters.

Educational Materials and Informed Consent

  • Educational Materials:
    • All allogeneic donors receive educational information explaining the safety of blood products in relation to Acquired Immunodeficiency Syndrome (AIDS) epidemiology.
    • Materials explicitly outline the implications of engaging in high-risk activities associated with HIV transmission.
    • Donors are instructed to refrain from donating if they have engaged in high-risk behaviors or experienced signs and symptoms indicative of HIV/AIDS.
  • AIDS Signs and Symptoms Mandating Self-Deferral:
    • Unexplained weight loss
    • Night sweats
    • Swollen lymph nodes persisting for ≥1 month\ge 1\,\text{month}
    • Persistent cough and shortness of breath
    • Oral body temperature >100.5∘F> 100.5^\circ\text{F}
    • Persistent diarrhea
  • Informed Consent Standards:
    • Mandated by AABB Standards for all allogeneic, autologous, and apheresis blood donors.
    • Donors must be informed of the medical risks inherent to the phlebotomy or apheresis procedure.
    • Donors must be informed of the panel of infectious disease tests conducted to minimize the risk of pathogen transmission to the recipient.
  • Confidential Unit Exclusion (CUE):
    • Every donor must be provided a confidential mechanism to indicate whether their donated blood is safe for transfusion.
    • CUE may be exercised during or after the donation process.
    • Available CUE mechanisms include:
    • Affixing a designated barcode sticker to a confidential ballot.
    • Applying a specific CUE barcode sticker to the collection bag or donor record card.
    • Calling a toll-free telephone number anonymously post-donation.

Donor Registration and Health History Interview

  • Registration Data Requirements:
    • Donor's full legal name
    • Permanent address and current contact information
    • Date of birth (to verify minimum age requirements)
    • Gender
    • Date of last blood donation
  • Health History Interview Structure:
    • Conducted in a private setting by qualified personnel.
    • Categorized into two primary types of questions:
    • Questions designed to protect the donor (e.g., questions evaluating pregnancy history or cardiovascular conditions).
    • Questions designed to protect the recipient from transfusion-transmitted pathogens or adverse drug exposure.
    • Outcome of the medical evaluation places potential donors into specific categories: accepted, temporarily deferred, or indefinitely/permanently deferred.

Medical Deferral Criteria

  • Indefinite and Permanent Deferrals:
    • History of viral hepatitis diagnosed after the donor's eleventh birthday.
    • Confirmed positive test for Hepatitis B surface antigen (HBsAg).
    • Reactive test for antibodies to Hepatitis B core antigen (anti-HBc) on more than one occasion.
    • Present or past clinical or laboratory evidence of infection with Hepatitis C virus (HCV), Human T-cell Lymphotropic Virus (HTLV), or Human Immunodeficiency Virus (HIV).
    • History of diagnosis with babesiosis or Chagas disease (Trypanosoma cruzi).
    • Family history of Creutzfeldt-Jakob Disease (CJD).
    • Recipient of human dura mater transplants or human pituitary-derived growth hormone.
    • Identified clinical risk for variant Creutzfeldt-Jakob Disease (vCJD).
    • History of nonprescription drug administration using a needle.
  • Temporary Deferrals (Specific Time Periods):
    • 2-Week Deferral:
    • Measles (rubeola) live attenuated vaccine
    • Mumps live attenuated vaccine
    • Polio (oral) vaccine
    • Typhoid (oral) vaccine
    • Yellow fever vaccine
    • 4-Week Deferral:
    • German measles (rubella) live attenuated vaccine
    • Varicella-zoster (chickenpox) live attenuated vaccine
    • 6-Week Deferral:
    • Conclusion of pregnancy
    • 12-Month Deferral:
    • Tattoo or permanent makeup application (unless applied by a state-regulated facility using sterile, non-reused needles and ink)
    • Mucous membrane or non-sterile skin penetration exposure to human blood
    • Sexual contact with an individual at high risk for HIV infection
    • Incarceration in a correctional institution for >72 consecutive hours> 72\,\text{consecutive hours}
    • Completion of antibiotic therapy for syphilis
    • Transfusion of whole blood, blood components, human tissue, or plasma-derived clotting factor concentrates
    • Administration of human diploid cell-rabies vaccine following an animal bite
  • Transfusion-Transmitted Infection Specific Deferrals:
    • Malaria (Plasmodium species):
    • History of malaria: deferred for 3 years.
    • Lived in a malaria-endemic area for 5 consecutive years: deferred for 3 years from departure.
    • Travel to a malaria-endemic area: deferred for 1 year from departure.
    • Babesiosis (Babesia microti): History of infection results in an indefinite deferral.
    • Chagas Disease (Trypanosoma cruzi): History of infection results in an indefinite deferral.
    • Leishmaniasis: Travel to Iraq results in a 1-year deferral from departure date.
    • vCJD Specific Exposure Rules:
    • Received a blood transfusion in the United Kingdom from 1980 to present: indefinite deferral.
    • Lived ≥3 months\ge 3\,\text{months} in the United Kingdom between 1980 and 1996: indefinite deferral.
    • Lived ≥5 years\ge 5\,\text{years} in Europe from 1980 to present: indefinite deferral.
    • Member of the U.S. military, civilian military employee, or dependent of a military member stationed in Europe between 1980 and 1996: indefinite deferral.
  • Medication-Based Acceptance and Deferrals:
    • Commonly Accepted Medications (provided donor is asymptomatic):
    • Bedtime hypnotics
    • Antihypertensive medications (if cardiovascularly stable and free of side effects)
    • Over-the-counter bronchodilators
    • Nasal decongestants
    • Oral contraceptives
    • Hormone replacement therapies
    • Weight-reduction medications
    • Mild analgesics
    • Supplemental vitamins
    • Tetracyclines or other systemic antibiotics taken strictly for acne treatment
    • Medication Deferral Schedules:
    • Finasteride (Proscar) [Benign Prostatic Hyperplasia]: 1-month deferral.
    • Finasteride (Propecia) [Male Pattern Baldness]: 1-month deferral.
    • Dutasteride (Avodart, Jalyn) [Benign Prostatic Hyperplasia]: 6-month deferral.
    • Isotretinoin (Accutane, Amnesteem, Claravis, Sotret) [Severe Acne]: 1-month deferral.
    • Acitretin (Soriatane) [Severe Psoriasis]: 3-year deferral.
    • Etretinate (Tegison) [Severe Psoriasis]: Indefinite deferral.
    • Warfarin (Coumadin) [Anticoagulation]: 1-week deferral.
    • Bovine insulin [Diabetes Mellitus]: Indefinite deferral.
    • Aspirin and piroxicam (Feldene) [NSAIDs]: 2-day deferral post-last dose for platelet donors.
    • Clopidogrel (Plavix) and ticlopidine (Ticlid) [Antiplatelet Agents]: 14-day deferral for platelet donors.
    • Hepatitis B Immune Globulin (HBIG) [Post-exposure Prophylaxis]: 1-year deferral.

Physical Examination Requirements

  • Required Parameter Thresholds for Allogeneic Donation:
    • General Appearance: Must appear in good health and be free of acute illness.
    • Hemoglobin:
    • Females: ≥12.5 g/dL\ge 12.5\,\text{g/dL} (125 g/L125\,\text{g/L})
    • Males: ≥13.0 g/dL\ge 13.0\,\text{g/dL} (130 g/L130\,\text{g/L})
    • Hematocrit:
    • Females: ≥38%\ge 38\%
    • Males: ≥39%\ge 39\%
    • Blood Pressure:
    • Systolic: 90–180 mmHg90\text{--}180\,\text{mmHg}
    • Diastolic: 50–100 mmHg50\text{--}100\,\text{mmHg}
    • Body Temperature: ≤37.5∘C\le 37.5^\circ\text{C} (99.5∘F99.5^\circ\text{F})
    • Pulse Rate: 50–100 beats/minute50\text{--}100\,\text{beats/minute} (regular rhythm; athletic donors may have lower baseline pulse rates)
    • Body Weight: Minimum 110 lb110\,\text{lb} (50 kg50\,\text{kg})
    • Age: Must conform to applicable state legal requirements or be >16 years> 16\,\text{years} of age.

Phlebotomy and Blood Collection Procedures

  • Pre-Phlebotomy Verification and Preparation:
    • Confirm donor identity against registration documents.
    • Primary collection bags, attached satellite bags, sample tubes, and registration forms must be labeled prior to venipuncture.
    • Select an acceptable venipuncture site in the antecubital fossa.
    • Skin preparation: Cleanse site thoroughly with a 0.7%0.7\%\ aqueous iodophor solution, followed by a 10%10\%\ povidone-iodine solution to ensure surgical antisepsis.
  • Venipuncture Procedure:
    • Performed by trained phlebotomists using an aseptic technique.
    • Collection utilizes a sterile, closed bag system equipped with a 16-gauge needle.
    • If venipuncture fails and must be repeated, a completely new sterile collection set and a different arm site must be used.
  • Collection Container Regulations:
    • Blood containers must be FDA approved, sterile, and pyrogen free.
    • Bags contain pre-measured volumes of anticoagulant-preservative solution tailored to the targeted blood collection volume.
    • Unique Donor Identification Number: A unique numeric or alphanumeric identification barcode must be applied to the donor record, the primary collection bag, and all satellite bags.
  • Adverse Donor Reactions and Management:
    • Mild Neurovascular Symptoms (Weakness, sweating, dizziness, pallor, nausea, vomiting):
    • Immediately remove needle and release tourniquet.
    • Elevate donor's legs above the level of the head.
    • Apply cold compresses to the forehead and back of the neck.
    • Syncope (Fainting):
    • Apply cold compresses to the back of the neck and monitor vital signs.
    • Twitching or Muscle Spasms:
    • Have the donor cough (disrupts hyperventilation/paresthesia patterns).
    • Hematoma Formation:
    • Remove needle, apply firm direct manual pressure to the site for 7–10 minutes7\text{--}10\,\text{minutes}, and apply ice to the affected area for 5 minutes5\,\text{minutes}.
    • Convulsions:
    • Call for immediate assistance.
    • Restrain donor gently to prevent falling from the donor chair or sustaining self-injury.
    • Maintain and protect the donor's airway.
    • Cardiac Difficulties:
    • Immediately initiate cardiopulmonary resuscitation (CPR) and activate emergency medical services.

Allogeneic, Autologous, Directed, and Therapeutic Donations

  • Allogeneic Donation: Blood collected from volunteer donors for general transfusion therapy across the patient population.
  • Autologous Donation: Blood donated by an individual strictly for their own anticipated future use.
    • Indications: Used primarily to cover predicted surgical blood loss in settings where homologous transfusions should be avoided or when compatible allogeneic units are unavailable (e.g., multiple alloantibodies).
    • Advantages: Eliminates risk of transfusion-transmitted viral infections, immune transfusion reactions, and red cell alloimmunization.
    • Disadvantages / Risks: Risk of bacterial contamination during storage, circulatory overload during reinfusion, cytokine-mediated reactions, and administrative product/recipient misidentification.
    • Types of Autologous Procedures:
    • Preoperative Donation: Blood is drawn and stored prior to an elective surgery date.
    • Normovolemic Hemodilution: Removal of units at the onset of surgery with concurrent volume replacement, followed by reinfusion at the conclusion of surgery.
    • Blood Recovery (Cell Salvage): Intraoperative collection where an intraoperative device washes, filters, and concentrates shed blood for reinfusion during surgery.
    • Preoperative Autologous Donation Criteria:
    • Standard high-risk health history questions do not apply.
    • No age restrictions.
    • If donor weight is <110 lbs< 110\,\text{lbs}, the drawn volume and anticoagulant amount are adjusted proportionally.
    • Hemoglobin must be ≥11 g/dL\ge 11\,\text{g/dL}.
    • Hematocrit must be ≥33%\ge 33\%
    • Donations can occur up to 72 hours prior to the scheduled surgery time.
  • Directed Donation:
    • Blood collected specifically for a designated recipient.
    • Must fulfill all standard allogeneic donor selection and testing criteria.
    • No clinical evidence demonstrates that directed donations are safer than standard allogeneic donations.
    • Units are labeled with a distinctively colored tag.
    • The standard 56-day donation interval may be waived if approved by the blood center medical director.
    • Graft-versus-Host Disease (GVHD) Prevention: If the directed donor is a biological blood relative, the unit must be irradiated prior to administration to prevent transfusion-associated GVHD.
  • Therapeutic Phlebotomy:
    • Phlebotomy performed as a medical treatment for underlying clinical disorders causing polycythemia or iron overload (e.g., Polycythemia Vera, Hereditary Hemochromatosis).
    • Must be prescribed by the patient's attending physician and approved by the blood bank medical director.
    • The medical prescription must explicitly state: exact volume of blood to be withdrawn, frequency of phlebotomy, and target post-phlebotomy hematocrit level.

Apheresis Collection Procedures

  • Mechanism of Apheresis:
    • Automated process that separates whole blood into individual components using centrifugal force based on specific component cellular densities.
    • The targeted blood component is harvested, while remaining blood components and intravascular fluids are returned to the donor/patient.
    • Allows collection of large volumes of specific components (platelets, plasma, leukocytes, red cells, stem cells).
    • Therapeutic apheresis: A pathological blood fraction is either permanently removed or passed through an absorptive column to clear toxic substances before returning blood to the patient.
  • Apheresis Categories and Parameters:
    • Leukapheresis: Harvests white blood cells (granulocytes).
    • Plateletpheresis:
    • Harvests platelets.
    • Minimum interval between donations: at least 48 hours.
    • Maximum frequency: no more than 2 times per week or 24 times per year.
    • Mandatory donor baseline platelet count: ≥150,000/μL\ge 150{,}000/\mu\text{L}.
    • Plasmapheresis:
    • Harvests plasma.
    • Infrequent Plasmapheresis: Performed no more than once every 4 weeks.
    • Frequent Plasmapheresis: Performed more often than once every 4 weeks; donor Immunoglobulin G (IgG) and Immunoglobulin M (IgM) serum levels must be monitored every 4 months.
    • Red Cell Apheresis (Double RBC Donation):
    • Harvests two units of red blood cells simultaneously.
    • Donors must meet elevated height and weight safety thresholds.
    • Mandatory deferral following a double RBC apheresis donation: 16 weeks (112 days).
  • Donation Intervals Overview:
    • Whole Blood Donation: Every 2 months (56 days).
    • Double Red Cell (ALYX): Every 4 months (112 days).
    • Plateletpheresis: Every 2 weeks.
    • Platelet / Plasma Concurrent Pheresis: Every 28 days.
    • Plasma-Only Pheresis: Every 28 days.

Blood and Component Labeling Standards

  • Regulatory Labeling Requirements:
    • All blood components must be labeled in full compliance with FDA regulations and AABB standards.
    • Standardized labeling conforms to ISBT 128 (International Society of Blood Transfusion) specifications, allowing global machine readability and standard terminology.
    • The ISBT 128 product name must be stated in parentheses following the established component title.

ISBT 128 Unit Label Format

  • Required Label Information:
    • Proper component name (including indication of chemical or physical modifications).
    • Preparation method (derived from whole blood vs. apheresis collection).
    • Required storage temperature range.
    • Standard volume or content count.
    • Number of individual units contained if pooled.
    • Expiration date and time.
    • Donor identification number and ABO/Rh blood type.
    • Facility name, address, registration number, and U.S. license number of the processing center.

Laboratory Processing and Screening Tests

  • Mandatory Testing Panel for Donor Blood:
    • ABO Group and Rh Type (including weak D testing on Rh-negative donors).
    • Unexpected Red Cell Antibody Screen.
    • Hepatitis B Virus (HBV): Tested via Hepatitis B surface antigen (HBsAg) and anti-Hepatitis B core antibody (anti-HBc).
    • Hepatitis C Virus (HCV): Antibody testing and Nucleic Acid Testing (NAT).
    • Human Immunodeficiency Virus (HIV): Anti-HIV-1/2 antibody and HIV NAT.
    • Human T-Cell Lymphotropic Virus: Anti-HTLV-I/II.
    • West Nile Virus (WNV): Tested via Minipool NAT (MP-NAT) or Individual Donation NAT (ID-NAT).
    • Syphilis: Serologic screening via Rapid Plasma Reagin (RPR), confirmed with Treponema pallidum Fluorescent Treponemal Antibody Absorption (FTA-ABS).
    • Chagas Disease: Anti-Trypanosoma cruzi antibody screening.
    • Zika Virus.
    • Ebola Virus (as indicated by regional public health directives).

Red Blood Cell Preservation and Storage Lesion

  • Storage Conditions:
    • Liquid red blood cells are stored at 1–6∘C1\text{--}6^\circ\text{C} to maintain cell viability and slow metabolic activity.
  • The Storage Lesion:
    • Refers to the collective biochemical, physiological, and structural changes occurring in red cells during in vitro liquid storage.
    • Biochemical Changes Included in Storage Lesion:
    • Decrease in pH.
    • Decrease in glucose consumption rate.
    • Accumulation of lactic acid byproduct.
    • Decrease in intracellular Adenosine Triphosphate (ATP) levels (leads to loss of membrane integrity and spherocyte formation).
    • Loss of 2,3-Diphosphoglycerate (2,3-DPG) levels.
    • Shift of the hemoglobin-oxygen dissociation curve to the left (increased oxygen affinity), causing a temporary reduction in oxygen release capacity at the tissue level post-transfusion.

Anticoagulants and Preservative Solutions

  • Primary Anticoagulants:
    • Acid-Citrate-Dextrose (ACD): Approved for whole blood and RBC storage; 21-day shelf life.
    • Citrate-Phosphate-Dextrose (CPD): Approved for whole blood and RBC storage; 21-day shelf life. Preferred over ACD because it better maintains higher 2,3-DPG levels for improved tissue oxygenation.
    • Citrate-Phosphate-Dextrose-Adenine (CPDA-1): Contains adenine to support ATP synthesis; extends RBC shelf life to 35 days.
    • Citrate-Phosphate-Double-Dextrose (CP2D): Contains double dextrose concentrations; 21-day shelf life.
  • Additive Solutions (AS):
    • Formulations added to packed red cells after primary plasma removal.
    • Restores nutrient fluids necessary to sustain metabolic functions during extended storage.
    • Included in satellite collection bags and introduced to RBCs post-centrifugation.
    • ADSOL (AS-1): Extends RBC shelf life to 42 days.
    • OPTISOL (AS-5): Extends RBC shelf life to 42 days.

Storage Requirements and Shelf Life of Blood Components

  • Summary Table of Component Shelf Life and Temperatures:
    • Whole Blood:
    • Shelf life: 35 days (in CPDA-1)
    • Storage temperature: 1–6∘C1\text{--}6^\circ\text{C}
    • Red Blood Cells (RBCs):
    • Shelf life: 35 days (in CPDA-1) or 42 days (with Additive Solution AS-1/AS-5)
    • Storage temperature: 1–6∘C1\text{--}6^\circ\text{C}
    • Washed RBCs:
    • Shelf life: 24 hours (due to open-system entry)
    • Storage temperature: 1–6∘C1\text{--}6^\circ\text{C}
    • Frozen RBCs:
    • Shelf life: 10 years (stored in high-glycerol cryoprotectant)
    • Storage temperature: ≤−65∘C\le -65^\circ\text{C}
    • Random Donor Platelets:
    • Shelf life: 5 days (under continuous agitation)
    • Storage temperature: 20–24∘C20\text{--}24^\circ\text{C}
    • Platelet Pheresis:
    • Shelf life: 5 days (under continuous agitation)
    • Storage temperature: 20–24∘C20\text{--}24^\circ\text{C}
    • Pooled Platelets:
    • Shelf life: 4 hours post-pooling
    • Storage temperature: 20–24∘C20\text{--}24^\circ\text{C}
    • Fresh Frozen Plasma (FFP):
    • Shelf life: 12 months
    • Storage temperature: ≤−18∘C\le -18^\circ\text{C}
    • Thawed Fresh Frozen Plasma:
    • Shelf life: 24 hours
    • Storage temperature: 1–6∘C1\text{--}6^\circ\text{C}
    • Cryoprecipitate (Frozen):
    • Shelf life: 12 months
    • Storage temperature: ≤−18∘C\le -18^\circ\text{C}
    • Cryoprecipitate (Pooled):
    • Shelf life: 4 hours post-pooling
    • Storage temperature: 20–24∘C20\text{--}24^\circ\text{C}
    • Granulocytes:
    • Shelf life: 24 hours
    • Storage temperature: 20–24∘C20\text{--}24^\circ\text{C}

Leukocyte Reduction Procedures

  • Indications:
    • Decreases the incidence of recurrent febrile non-hemolytic transfusion reactions (FNHTR) caused by recipient antibodies directed against donor HLA antigens/cytokines.
    • Reduces the rate of Human Leukocyte Antigen (HLA) alloimmunization in chronically transfused patients.
    • Decreases transfusion transmission risk of intracellular viruses such as Cytomegalovirus (CMV).

Leukoreduction Filter for RBCs

  • Clinical Constraints:
    • Leukoreduction does not prevent Graft-versus-Host Disease (GVHD).
    • Leukoreduction filters must never be used during the administration of granulocyte pheresis products.

Gamma Irradiation of Blood Products

  • Purpose and Mechanism:
    • Inhibits the proliferative capacity of donor T lymphocytes contained within cellular blood components.
    • Prevents Transfusion-Associated Graft-versus-Host Disease (TA-GVHD), a fatal immune complication.
    • Standard dose: 2500 cGy2500\,\text{cGy} (25 Gy) targeted directly to the central portion of the container, with a minimum dose of 1500 cGy1500\,\text{cGy} to all other parts.
    • Verification: A radiochromic verification indicator strip (e.g., RAD-SURE) is attached to the bag prior to processing; the indicator turns black once adequate irradiation exposure occurs.

Rad-Sure Irradiation Verification Label

  • Indications for Irradiated Products:
    • Intrauterine transfusions provided to fetuses.
    • Severely immunocompromised patients (e.g., severe combined immunodeficiency, chemotherapy patients).
    • Recipients receiving cellular components donated by biological blood relatives.
    • Patients receiving bone marrow or hematopoietic stem cell transplants.
    • Recipients receiving units specifically selected for HLA compatibility.
  • Effects of Irradiation on Product Expiration:
    • Causes membrane damage to red blood cells, leading to accelerated leakage of intracellular potassium into the supernatant fluid (K+K^+ levels are elevated).
    • Platelet expiration dates remain unaffected by gamma irradiation.
    • Irradiated RBC expiration dates are shortened to 28 days post-irradiation (or the original outdate, whichever occurs first).

Washing of Blood Components

  • Preparation Method:
    • Washed components are prepared using sterile 0.9%0.9\%\ Sodium Chloride (normal saline), with or without small concentrations of dextrose.
  • Clinical Purpose:
    • Removes unwanted residual plasma proteins, cellular debris, microaggregates, and residual antibodies (indicated for IgA-deficient recipients with anti-IgA antibodies or severe anaphylactic transfusion reaction histories).
  • Disadvantages:
    • Causes minor loss of functional red blood cells and platelets.
    • Decreases baseline functional activity of platelets.
  • Storage Limitations:
    • Breaking the closed system seal during washing reduces component shelf life to a maximum of 24 hours when stored at 1–6∘C1\text{--}6^\circ\text{C}, or 4 hours when stored at 20–24∘C20\text{--}24^\circ\text{C}.

Look-Back Process for Infectious Disease Reporting

  • Definition and Indications:
    • A mandatory regulatory series of trace actions performed by blood centers when a donor subsequently tests positive for viral markers (Hepatitis, HIV, HTLV, or West Nile Virus).
    • Applied to prior donations made by that donor during the clinical "window period" (when pathogen exposure occurred but original screening assays yielded false-negative results).
  • Sequential Steps in the Look-Back Procedure:
    1. Immediately quarantine all prior donations from that donor that currently remain in blood bank inventory.
    2. Formally notify receiving facilities to quarantine any un-transfused prior collections distributed to them.
    3. Perform supplementary and confirmatory infectious disease testing on the donor.
    4. Destroy or re-label all confirmed infected prior collections.
    5. Identify specific recipients who received blood components harvested from those prior donations.
    6. Notify the recipient's attending physician and/or the recipient directly regarding pathogen exposure as governed by FDA regulations.