Accurate PFAS testing is the essential foundation of any water safety program — without knowing which compounds are present and at what concentrations, choosing the right filtration approach is guesswork. But not all testing laboratories are created equal. Selecting a properly certified laboratory ensures your results are legally defensible, analytically accurate, and sufficient for regulatory compliance.
Why Laboratory Certification Matters for PFAS
PFAS analysis is among the most technically demanding in environmental chemistry. At the concentrations of concern — parts per trillion (ng/L) — even tiny sources of contamination can invalidate results. PFAS are ubiquitous in laboratory environments: they’re in many types of tubing, septa, gloves, food packaging in the lab breakroom, and even some cleaning products. Certified laboratories maintain rigorous contamination control protocols that uncertified labs may lack.
Additionally, PFAS analysis requires sophisticated instrumentation — typically liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) — and analyst expertise that represents significant investment. Certification programs verify that this infrastructure and expertise meet minimum standards.
The Key Certifications to Look For
NELAC/TNI Certification: The NELAC Institute (TNI) accreditation is the standard for environmental testing laboratories in the United States. Accredited labs must demonstrate proficiency through blind sample testing and pass on-site audits. Look for laboratories accredited specifically for PFAS analysis under EPA Methods 533 or 537.1.
State Laboratory Certification: Most states have their own laboratory certification programs that recognize TNI accreditation and/or add state-specific requirements. For regulatory compliance purposes — such as demonstrating compliance with state PFAS drinking water standards — results typically must come from a state-certified laboratory. Your state environmental agency’s website will list approved laboratories.
DoD/ELAP Certification: For testing near military installations (where AFFF contamination is a common concern), the Department of Defense Environmental Laboratory Accreditation Program (DoD ELAP) certification may be required for results used in remediation contexts.
Which EPA Method Should Your Lab Use?
Several EPA analytical methods are currently in use for PFAS in drinking water:
- EPA Method 537.1: Covers 40 PFAS compounds; has been the standard since 2018; uses solid-phase extraction followed by LC-MS/MS
- EPA Method 533: Published in 2019; covers 25 additional short-chain PFAS not covered by 537.1; particularly important given growing regulatory attention to PFBS, GenX, and other short-chain compounds
- EPA Method 533 + 537.1 combined: Some laboratories run both methods to provide comprehensive coverage of 60+ PFAS compounds
- Top 40/EPA Interim Method 8327: Used for wastewater; different matrix preparation requirements
For residential drinking water testing, requesting Method 533 alone or in combination with 537.1 provides the most comprehensive PFAS profile.
Sample Collection Requirements
Even with a perfectly calibrated laboratory, improper sample collection can invalidate results. Your laboratory should provide:
- Pre-cleaned, PFAS-free sample bottles (typically 250 mL HDPE)
- Chain-of-custody documentation
- Specific instructions for sample collection (typically first-draw from the cold tap after allowing water to stand overnight)
- Temperature and hold-time requirements for sample shipment
Do not use laboratory bottles for any purpose other than the PFAS sample, and avoid contact with potentially PFAS-containing materials (food packaging, nylon-lined gloves) during collection.
Cost Expectations and Finding Certified Labs
PFAS testing through certified laboratories typically costs:
- Single method (537.1 or 533): $150–$300 per sample
- Combined methods (537.1 + 533): $300–$500 per sample
- Expedited turnaround (5–10 days vs. standard 14–21 days): Additional premium of 25–50%
Resources for finding certified labs include:
- The TNI online laboratory search tool at nelac-institute.org
- Your state environmental agency’s approved laboratory list
- EPA’s Safe Drinking Water Hotline (1-800-426-4791)
Mail-in consumer PFAS test kits (e.g., SimpleLab, Tap Score) use certified partner laboratories and can be a convenient option, though they typically test a more limited PFAS panel than a full professional analysis.