Title 42 Part 493 → Subpart I → §493.927

Title 42 → Chapter IV → Subchapter G → Part 493 → Subpart I → §493.927

Electronic Code of Federal Regulations e-CFR

Title 42 Part 493 → Subpart I → §493.927

e-CFR data is current as of January 16, 2020

Title 42Chapter IVSubchapter GPart 493Subpart I → §493.927

Title 42: Public Health
Subpart I—Proficiency Testing Programs for Nonwaived Testing

§493.927   General immunology.

(a) Program content and frequency of challenge. To be approved for proficiency testing for immunology, the annual program must provide a minimum of five samples per testing event. There must be at least three testing events at approximately equal intervals per year. The annual program must provide samples that cover the full range of reactivity from highly reactive to nonreactive. The samples may be provided through mailed shipments or, at HHS' option, may be provided to HHS or its designee for on-site testing.

(b) Challenges per testing event. The minimum number of challenges per testing event the program must provide for each analyte or test procedure is five. Analytes or tests for which laboratory performance is to be evaluated include:

Analyte or Test Procedure

Alpha-l antitrypsin

Alpha-fetoprotein (tumor marker)

Antinuclear antibody

Antistreptolysin O

Anti-human immunodeficiency virus (HIV)

Complement C3

Complement C4

Hepatitis markers (HBsAg, anti-HBc, HBeAg)





Infectious mononucleosis

Rheumatoid factor


(c) Evaluation of a laboratory's analyte or test performance. HHS approves only those programs that assess the accuracy of a laboratory's responses in accordance with paragraphs (c)(1) through (5) of this section.

(1) To determine the accuracy of a laboratory's response for quantitative and qualitative immunology tests or analytes, the program must compare the laboratory's response for each analyte with the response that reflects agreement of either 80 percent of ten or more referee laboratories or 80 percent or more of all participating laboratories. The proficiency testing program must indicate the minimum concentration that will be considered as indicating a positive response. The score for a sample in general immunology is either the score determined under paragraph (c)(2) or (3) of this section.

(2) For quantitative immunology analytes or tests, the program must determine the correct response for each analyte by the distance of the response from the target value. After the target value has been established for each response, the appropriateness of the response must be determined by using either fixed criteria or the number of standard deviations (SDs) the response differs from the target value.

Criteria for Acceptable Performance

The criteria for acceptable performance are—

Analyte or test Criteria for acceptable performance
Alpha-1 antitrypsinTarget value ±3 SD.
Alpha-fetoprotein (tumor marker)Target value ±3 SD.
Antinuclear antibodyTarget value ±2 dilutions or positive or negative.
Antistreptolysin OTarget value ±2 dilution or positive or negative.
Anti-Human Immunodeficiency virusReactive or nonreactive.
Complement C3Target value ±3 SD.
Complement C4Target value ±3 SD.
Hepatitis (HBsAg, anti-HBc, HBeAg)Reactive (positive) or nonreactive (negative).
IgATarget value ±3 SD.
IgETarget value ±3 SD.
IgGTarget value ±25%.
IgMTarget value ±3 SD.
Infectious mononucleosisTarget value ±2 dilutions or positive or negative.
Rheumatoid factorTarget value ±2 dilutions or positive or negative.
RubellaTarget value ±2 dilutions or immune or nonimmune or positive or negative.

(3) The criterion for acceptable performance for qualitative general immunology tests is positive or negative.

(4) To determine the analyte testing event score, the number of acceptable analyte responses must be averaged using the following formula:

eCFR graphic er25se06.023.gif

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(5) To determine the overall testing event score, the number of correct responses for all analytes must be averaged using the following formula:

eCFR graphic er25se06.022.gif

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[57 FR 7151, Feb. 28, 1992, as amended at 58 FR 5229, Jan. 19, 1993; 68 FR 3702, Jan. 24, 2003]