An ISO 17025 accredited testing facility is a laboratory that has been independently evaluated and certified to meet the international standard for technical competence in testing and calibration. This accreditation, governed by ISO/IEC 17025:2017, confirms that the laboratory produces valid, reliable results through qualified personnel, validated methods, calibrated equipment, and a rigorous quality management system that is regularly audited by an independent accrediting body.

What ISO 17025 Means in Practice

The ISO/IEC 17025 standard is often cited but rarely explained in a way that helps clients understand what it actually means for the results they receive. At its core, the standard addresses two fundamental questions: Does the laboratory have the technical competence to perform the tests correctly? And does the laboratory have a management system that ensures consistent quality over time?

Technical Competence Requirements

The technical requirements of ISO 17025 cover every aspect of the testing process that can affect the quality of results:

• Personnel qualifications: Every analyst must demonstrate competence for the specific methods they perform. This includes formal education, training on the specific method, supervised practice, and ongoing proficiency verification. At AATLS, analysts complete a documented training program for each method and must pass a competency assessment before performing the method independently.
• Equipment and calibration: All instruments used in testing must be properly calibrated and maintained. Calibration must be traceable to national or international standards (NIST in the United States). Calibration records, maintenance logs, and performance verification data are maintained for every instrument.
• Method validation: Before a laboratory can report results using a particular method, it must demonstrate that it can perform the method correctly. This involves analyzing reference materials, participating in proficiency testing, and documenting method performance characteristics including accuracy, precision, detection limits, and measurement uncertainty.
• Sample handling: The standard requires documented procedures for receiving, identifying, storing, and disposing of samples. Every sample must be uniquely identified and traceable throughout the testing process.
• Environmental conditions: Laboratory conditions (temperature, humidity, air quality, vibration) must be controlled and monitored to ensure they do not adversely affect test results.

Management System Requirements

The management system component of ISO 17025 ensures that the technical competence is sustained over time:

• Document control: All procedures, methods, and forms are controlled documents with defined revision histories. Analysts always work from the current approved version of a method.
• Corrective and preventive action: When errors or nonconformities are identified, the laboratory must investigate root causes, implement corrective actions, and verify their effectiveness.
• Internal audits: The laboratory conducts regular internal audits to verify compliance with its own quality management system and the ISO 17025 standard.
• Management reviews: Laboratory leadership regularly reviews quality system performance, including audit results, proficiency testing outcomes, customer feedback, and corrective action effectiveness.
• Continuous improvement: The standard requires a systematic approach to identifying and implementing improvements in laboratory operations.

The Accreditation Process

Achieving ISO 17025 accreditation is not a simple paperwork exercise. The process typically takes 12 to 18 months for a new laboratory and involves:

1. Developing a quality management system that meets all requirements of the standard.
2. Implementing the system and operating under it for a sufficient period to demonstrate consistent performance.
3. Submitting an application to an accrediting body (such as A2LA, PJLA, or ANAB in the United States).
4. Undergoing a thorough document review by the accrediting body’s technical assessors.
5. Hosting an on-site assessment where assessors observe laboratory operations, review records, interview personnel, and verify compliance with every element of the standard.
6. Addressing any findings or nonconformities identified during the assessment.
7. Receiving the accreditation certificate and scope, which lists the specific methods the laboratory is accredited to perform.

After initial accreditation, the laboratory undergoes surveillance assessments annually and a full reassessment every two to four years, depending on the accrediting body. This ongoing oversight ensures that accredited laboratories maintain their competence and compliance over time.

Walking Through the AATLS Facility

Our laboratory at 9030 S Rita Rd, Suite 320, Tucson, AZ 85747 is designed and equipped to support the diverse range of analytical testing we perform for our clients across Arizona and beyond. Here is what you would see on a walk through our facility.

Sample Receiving and Login

Every sample that enters AATLS passes through our sample receiving area first. This is where the chain of custody begins, and it is one of the most important steps in the entire analytical process.

When samples arrive, our receiving team:

• Verifies the sample condition against the chain of custody documentation.
• Checks that samples are in the correct containers with proper preservatives.
• Verifies that temperature requirements have been maintained during transport. Cooler temperatures are documented using calibrated thermometers.
• Assigns unique laboratory identification numbers to each sample.
• Logs samples into our Laboratory Information Management System (LIMS), which tracks every sample from receipt through reporting.
• Routes samples to the appropriate storage locations based on their testing requirements and hold times.

Any discrepancies between the chain of custody and the samples received are documented and communicated to the client immediately. This attention to detail at the point of receipt prevents errors that could compromise results downstream.

Sample Storage

Proper sample storage is critical because many analytes are time-sensitive and temperature-sensitive. Our storage areas include:

• Refrigerated storage (2-6 degrees Celsius): For samples requiring cold storage, including most water chemistry and microbiological samples. Refrigerators are continuously monitored with calibrated temperature dataloggers that alert staff if temperatures drift outside acceptable ranges.
• Freezer storage (-20 degrees Celsius): For samples requiring frozen storage, including certain organic chemistry and PFAS samples.
• Ambient storage: For samples and standards that are stable at room temperature. The laboratory ambient temperature is maintained at 20-25 degrees Celsius and continuously monitored.

Microbiology Laboratory

Our microbiology laboratory is where we analyze samples for bacteria, including total coliform, E. coli, Legionella, heterotrophic plate count (HPC), and other microbiological parameters. As a CDC ELITE certified laboratory for Legionella testing, this area meets the enhanced quality requirements established by the Centers for Disease Control and Prevention’s Environmental Legionella Isolation Techniques Evaluation program.

Key features of our microbiology lab include:

• Biosafety Level 2 (BSL-2) practices: Our microbiology work follows BSL-2 protocols appropriate for handling organisms that can cause moderate hazard to personnel.
• Laminar flow hoods: Sample processing for microbiological analysis is performed in biological safety cabinets that provide a sterile work environment and protect the analyst and the sample from contamination.
• Incubators: Multiple incubators maintained at specific temperatures for different organisms. Legionella culture requires incubation at 35-37 degrees Celsius for up to 14 days. Coliform analyses use incubators at 35 degrees Celsius for 24 hours.
• Autoclaves: Used to sterilize media, glassware, and waste. Autoclave performance is verified with biological indicators and temperature monitoring.
• BCYE agar preparation: For Legionella culture, we prepare Buffered Charcoal Yeast Extract agar in-house following CDC ELITE specifications. Media quality is verified with reference organisms before use with client samples.

Our CDC ELITE certification for Legionella means that we have demonstrated proficiency in isolating and identifying Legionella species from environmental samples. This certification requires annual proficiency testing with blind samples provided by the CDC. Learn more about our Legionella testing capabilities on our testing services page.

Inorganic Chemistry Laboratory

Our inorganic chemistry laboratory handles metals analysis, general chemistry, and nutrient testing. This is where we analyze samples for parameters like lead, copper, arsenic, mercury, nitrates, fluoride, pH, hardness, total dissolved solids, and dozens of other inorganic analytes.

Major instruments in this area include:

• ICP-MS (Inductively Coupled Plasma Mass Spectrometry): Our workhorse instrument for trace metals analysis. ICP-MS can detect metals at parts-per-trillion concentrations, making it ideal for measuring lead, arsenic, mercury, cadmium, and other toxic metals at the low levels required by EPA drinking water standards. A single ICP-MS analysis can simultaneously measure more than 30 different metals in a sample.
• ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry): Used for metals at higher concentrations and for elements that are better suited to optical emission detection. This instrument is commonly used for wastewater, soil digest, and industrial process water analyses.
• Ion chromatography (IC): Used for anion analysis including fluoride, chloride, nitrate, nitrite, sulfate, and phosphate. IC provides precise quantification of these parameters at the low levels required for drinking water compliance.
• pH, conductivity, and TDS meters: Calibrated daily with NIST-traceable standards for general water quality parameters.
• UV-Vis spectrophotometry: Used for colorimetric analyses including certain nutrient and water quality parameters.

Organic Chemistry Laboratory

Our organic chemistry laboratory is equipped for the analysis of organic contaminants including PFAS, volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), pesticides, and other organic analytes.

• LC-MS/MS (Liquid Chromatography Tandem Mass Spectrometry): This advanced instrument is essential for PFAS analysis under EPA Method 533 and 537.1. It can detect PFAS compounds at parts-per-trillion concentrations, meeting the new EPA MCLs of 4 ppt for PFOA and PFOS. The instrument separates complex mixtures by liquid chromatography and identifies individual compounds by their mass spectral fingerprints.
• GC-MS (Gas Chromatography Mass Spectrometry): Used for volatile and semi-volatile organic compound analysis. Essential for environmental site assessments, industrial wastewater monitoring, and contamination investigations.
• Sample preparation areas: Dedicated areas for liquid-liquid extraction, solid-phase extraction, and other sample preparation techniques. These areas are designed to minimize cross-contamination between samples and between different analyte classes.

Quality Control Laboratory

While quality control is integrated into every analytical area, we maintain a dedicated QC function responsible for:

• Reference standard preparation and verification: Calibration standards are prepared from NIST-traceable reference materials and verified against independent sources.
• Proficiency testing coordination: AATLS participates in proficiency testing programs for every method on our accredited scope. PT samples are analyzed blind (the true values are not known to the analysts) and results are evaluated by the PT provider against acceptance criteria.
• Method blank monitoring: Every analytical batch includes method blanks to verify that no contamination has been introduced by the laboratory’s reagents, glassware, or procedures.
• Control chart maintenance: QC data is plotted on control charts to track method performance over time and identify trends before they become problems.

Data Review and Reporting

Before any results leave our laboratory, they undergo a rigorous multi-level review process:

1. Analyst review: The analyst who performed the testing reviews all data, QC results, and calculations.
2. Peer or supervisory review: A second qualified individual reviews the data package for completeness, accuracy, and compliance with method requirements.
3. QA review: The quality assurance function performs a final check to ensure all QC acceptance criteria have been met and the data package is complete.
4. Report generation: Results are compiled into a formal laboratory report that includes all analytical results, applicable regulatory limits, method detection limits, QC data, and laboratory accreditation information.

Reports are delivered electronically through secure channels. Our LIMS ensures complete traceability from sample receipt through final reporting, with a full audit trail of every action taken on every sample.

Chain of Custody: Protecting the Integrity of Your Data

Chain of custody (COC) is the documented, unbroken trail that records the possession, handling, and analysis of a sample from the moment it is collected to the final reporting of results. Proper chain of custody is essential for regulatory compliance, legal defensibility, and scientific integrity.

Why Chain of Custody Matters

Without proper chain of custody, analytical results can be challenged or rejected. This is particularly important for:

• Regulatory compliance: EPA, state agencies, and local health departments require documented chain of custody for compliance monitoring results.
• Legal proceedings: In litigation, contamination cases, and enforcement actions, chain of custody documentation is essential for results to be admissible as evidence.
• Building water management: Legionella testing results used for healthcare facility compliance must have documented chain of custody to satisfy CMS (Centers for Medicare and Medicaid Services) and Joint Commission requirements.
• Real estate transactions: Lenders require chain of custody documentation for water testing associated with FHA and VA loans.

AATLS Chain of Custody Procedures

Our chain of custody process includes:

• Pre-printed COC forms that capture sampler information, sample identification, date and time of collection, preservation method, requested analyses, and any special instructions.
• Tamper-evident seals on sample containers when required for legal or regulatory purposes.
• Documentation of every transfer of custody, from the sampler to the courier to the laboratory receiving staff.
• LIMS tracking that records every action taken on the sample within the laboratory, including who performed each step and when.
• Secure sample storage with controlled access.
• Documented sample disposal procedures after analysis is complete and holding times have been satisfied.

How Results Are Validated

Result validation at AATLS is a systematic process designed to catch errors before they reach the client. Every reported result has been verified through multiple independent checks.

Calibration Verification

Before any samples are analyzed, instrument calibration is verified using standards of known concentration. Calibration must meet defined acceptance criteria (typically within 10 percent of the true value) before sample analysis can proceed. Continuing calibration verification (CCV) standards are analyzed throughout the analytical run to confirm that calibration remains valid.

Quality Control Samples

Every analytical batch includes:

• Method blanks: Must be free of target analytes above method detection limits to verify no laboratory contamination.
• Laboratory control samples (LCS): Standards of known concentration that must recover within defined acceptance ranges (typically 80-120 percent) to verify method accuracy.
• Matrix spikes: Client samples spiked with known quantities of target analytes to evaluate the effect of the sample matrix on method performance.
• Laboratory duplicates: Replicate analyses to assess method precision. Duplicate results must agree within defined relative percent difference criteria.

If any QC sample fails its acceptance criteria, the associated client results are flagged and may require reanalysis. The cause of the QC failure is investigated and documented.

Proficiency Testing

AATLS participates in proficiency testing programs administered by independent PT providers. Twice per year (at minimum), we analyze blind samples with unknown concentrations and submit our results for evaluation. Our results are compared against the true values and against the results of other participating laboratories. Satisfactory PT performance is a requirement for maintaining our ISO 17025 accreditation.

What Makes AATLS Different

While any accredited laboratory can produce valid analytical results, AATLS distinguishes itself through several characteristics that matter to our clients.

Veteran-Owned and Operated

AATLS was founded by Dr. Glenn Cherry, a United States Air Force veteran and Doctor of Veterinary Medicine. The discipline, attention to detail, and commitment to mission that characterize military service are embedded in our laboratory culture. We approach every sample with the same rigor and accountability, whether it is a single homeowner’s water test or a large-scale environmental monitoring program. Learn more about us and our founding story.

CDC ELITE Certified for Legionella

AATLS is one of a limited number of laboratories nationwide that holds CDC ELITE certification for Legionella testing. The ELITE (Environmental Legionella Isolation Techniques Evaluation) program is administered by the Centers for Disease Control and Prevention and requires laboratories to demonstrate proficiency in isolating and identifying Legionella species from environmental water samples. This certification is essential for healthcare facilities, hotels, and other buildings that must comply with ASHRAE Standard 188 and CMS requirements for Legionella water management programs. With approximately 10,000 cases of Legionnaires’ disease reported annually in the United States and an estimated case fatality rate of about 10 percent, accurate Legionella testing is literally a matter of life and death.

Local Arizona Laboratory

Being based in Tucson, Arizona means our clients benefit from:

• Shorter sample transit times: Samples from anywhere in Arizona can reach our laboratory within 24 hours by courier or overnight shipping. Local samples can be hand-delivered the same day. Shorter transit times mean samples are analyzed closer to the time of collection, which is particularly important for time-sensitive parameters like bacteria.
• Local knowledge: We understand Arizona’s water quality challenges, from naturally occurring arsenic and fluoride to PFAS contamination near military installations. This local expertise helps us guide clients to the right testing programs for their specific situations.
• Accessible service: Our clients can reach a real person who understands their needs. We are not a call center; we are a team of scientists who are invested in producing the best possible results for every client.

Comprehensive Testing Menu

AATLS provides analytical testing across multiple disciplines, including:

• Water testing (drinking water, wastewater, environmental water)
• Legionella testing (CDC ELITE certified culture method)
• Lead and copper testing for schools, daycares, and residential properties
• PFAS testing (EPA Methods 533 and 537.1)
• Environmental testing (soil, sediment, air)
• Cosmetic and consumer product testing
• Agricultural testing

This breadth of capability means our clients can consolidate their testing with a single accredited laboratory, simplifying vendor management and ensuring consistent quality across all their analytical needs. Explore our full testing services menu.

Visiting AATLS

We welcome clients and prospective clients to visit our facility. Seeing a laboratory in person gives you a tangible understanding of the quality systems, equipment, and people behind your analytical results. During a visit, you can:

• Tour the laboratory and see the instruments and processes described in this article firsthand.
• Meet the scientists and technicians who will be analyzing your samples.
• Review our quality systems and accreditation documentation.
• Discuss your specific testing needs and develop a customized analytical program.

To schedule a lab tour, contact us at (928) 985-9399 or visit aatls.com/contact-us.