Who should participate in the IHP​AT Program?

If a laboratory analyzes samples taken from the workplace environment, then participation in the IHPAT Program can provide information to clients on laboratory performance. In addition, a laboratory must be a part of a proficiency testing program to meet accreditation and/or regulatory requirements.

What types of samples will be used in the ​program?

The analytes covered under the IHPAT Program include metals, silica, asbestos, solvents, and diffusive sampler badges. Laboratories that elect to enroll in the diffusive sampler program do so through the IHPAT Program.

IHPAT rounds occur four times a year. Diffusive Sampler rounds occur twice a year and coincide with the even-numbered IHPAT rounds. Airborne Particulate rounds occur twice a year and coincide with the odd-numbered IHPAT rounds.

Analyte Class


Number of Samples


Concentration Range
(general range)

Airborne Particulates

37-mm, 5-µm PVC filter

4 samples

Airborne particulates by methods NIOSH 0500, 0600, and 5000

0.5-5 mg per filter


0.8 µm, 25mm MCE (mixed cellulose ester) filter

4 fiber samples
2 blank

Amosite, Chrysotile, and Man-Made fibers

Asbestos: 100-800 fibers/ mm2 of filter surface
Man-made fibers: 60-125 fibers/ mm2 of filter surface

Diffusive Sampler*

Assay Technology (566AT) or SKC (575-002) diffusive sampler badge

2 samples, per contaminant

Benzene, toluene, and o-xylene

Benzene: 1 ppm - 32 ppm
o-Xylene: 8 ppm - 32 ppm
Toluene: 8 ppm - 37 ppm

MercurySKC 226-17-1A Solid Sorbent Tube4 samples, 1 blankMercury0.1 µg to 1.2 µg per tube


0.8 µm, 37mm MCE (mixed cellulose ester) filter

4 samples, per contaminant
1 blank

Lead, Cadmium, and one from: Nickel, Manganese, or Chromium (rotated each round)

Metals (other than Cadmium): 0.02 mg – 0.2 mg
Cadmium: 0.002 mg – 0.04 mg

Organic Solvents*

Anasorb CSC coconut charcoal

4 samples, per contaminant
5 blanks (determination of desorption efficiency)

Coconut charcoal: rotated between benzene, ethyl acetate, n-butyl acetate, 2-propanol, 1-bromopropane, chloroform, 1,2-dichloroethane, o-xylene, toluene, or trichlorethylene

Organic Solvents (other than chloroform): 0.03 mg – 2 mg
Chloroform: 0.125 mg – 2 mg


5.0 µm, 37mm PVC (polyvinyl chloride) filter

4 samples
1 blank

Free silica (quartz); include a background matrix, (rotating basis) of coal mine dust, talc, calcite, or a combination of talc and coal mine dust

0.025 mg – 0.225 mg

* AIHA Proficiency Analytical Testing Programs (PAT Programs), Falls Church, VA, is accredited by A2LA (Certificate Number 3300.01) for the programs indicated.

​How are proficiency samples sent?

Proficiency samples are shipped via a trackable carrier. Upon receipt of the IHPAT samples, it is the responsibility of the laboratory to inspect the shipment for any damage and to ensure that the correct samples were received. If samples are damaged, the laboratory shall notify the PAT Programs within 24 hours of sample receipt to ensure timely replacement of samples for the laboratory to meet the deadline for submission of data. Laboratories requesting special shipping for replacement samples shall assume the cost of express carrier handling.

If the IHPAT samples are not received by the laboratory in accordance with the predefined schedule, then it shall be the responsibility of the laboratory to contact the PAT Programs within one (1) week of the scheduled shipping date to notify us of failure to receive the PT samples. A laboratory that receives IHPAT samples but does not submit results by the deadline will receive a "Fail" for the round.

When is the next round of IHPAT and when is the deadline to sign up?

Please see the Program Schedule for all important dates and deadlines.

Are special analytical methods required?

Except for IHPAT Asbestos (NIOSH 7400), the IHPAT Program does not specify which analytical methods laboratories should use. Participants are required to treat proficiency test items in the same manner as most routinely tested samples. This allows the effectiveness of the analytical methods used by the laboratory to be tested.

What happens after the results are submitted?

After the close of the IHPAT round, the results are statistically evaluated, and a proficiency report is generated for each participating laboratory. Each laboratory will receive an e-mail notification once the results are available on the PAT Programs website. PAT Programs provides an opportunity to improve round performance by making retest samples available. Results from the retest round replace results from the previous round.

How is proficiency determined?

Rounds are scored at the analyte class level (asbestos, diffusive sampler, metals, organic solvents, and silica). The round pass/fail determination is made based upon the number of acceptable ratings in the analyte class. To pass, ≥75% of samples must be scored as acceptable. The acceptability of reported results is based on upper and lower acceptance limits. A laboratory is rated proficient for the analyte class if the laboratory has a passing score in two of the last three consecutive PT rounds.

What happens if my laboratory is non-proficient?

If non-proficient, a laboratory may choose to participate in a retest round to attempt to regain proficient status. The retest results will replace the original results submitted by the laboratory and proficiency will be evaluated based upon the retest round pass/fail determination. Retest samples may also be used to expedite initial proficiency for a new program or when adding an analyte to an existing program. A retest sample order form is available on the PAT Programs website.

Does PAT Programs provide ​QC samples?

PAT Programs offer stock samples from previous rounds for laboratories wishing to evaluate analytical procedures and quality control systems. Certificates of analysis are provided with the samples to allow evaluation of how well the laboratory performed. Kits consist of four concentration levels for each analyte, which include metals, asbestos, silica, and organic solvents. Blanks are provided with each analyte. A stock sample order form is available on the PAT Programs homepage.

Who prepares the proficiency testing samples?

IHPAT samples are generated, verified, and shipped by RTI International on behalf of the PAT Programs. PAT Programs collects and analyzes IHPAT data and distributes participant reports.

Please contact PAT Programs at info.PATLLC@aiha.org​ for more information about the Industrial Hygiene Proficiency Analytical Testing (IHPAT) Program.​​​​​​​​​​​​​

Last Updated: 03/29/2024 01:21PM