©American
Society for Veterinary Clinical Pathology |
Principles of Quality Assurance and Standards
for Veterinary Radioimmunoassay (RIA)
I. Preanalytical Factors Important in RIA
II. Analytical Factors Important in RIA
III. Postanalytical Factors Important in RIA
I. Preanalytical Factors Important in RIA [Return to Top]
A. Government Regulations for RIA
Government regulations and licensing requirements may vary with city, state, province and country. In general, minimum requirements for safe radioisotope handling are indicated. Requirements include personnel safety training, radioactive isotope monitoring, proper radioisotope disposal, and periodic inspection. Licensing is required for the purchase of radioactive isotopes. A laboratory considering performing RIAs should first determine whether it meets these standards and obtain licensure before establishing the procedures.
B. Specimen Collection, Handling, and Transport to the Laboratory
Samples should be appropriately collected, handled and transported to the laboratory in a timely manner, dependent on the type of specimen and its stability. For any assay performed in the laboratory, information concerning sample requirements, proper collection, handling, and delivery or shipping procedures should be available to clients in a laboratory services manual, special information sheets, journal or newsletter articles, other written materials, or by personal or telephone conversation.
C. Specimen Identification
Specimens should be identified with pertinent information as determined by the laboratory (such as owner, species, animal signalment, name of clinic or doctor, address, telephone and fax numbers, e-mail address, location from which the specimen was collected, etc.) on the submission container and submission form.
D. Test Identification
The requested test(s) should be clearly stated on the submission form.
E. Specimen Accessioning
The specimen should be correctly entered into the laboratory system. Test request entry, delivery of the specimen to the correct location, and specimen aliquoting (if necessary) or sharing between laboratories or departments (ie, RIA and clinical chemistry) should be coordinated.
F. Client Communication and Education
Communication between laboratory personnel and clients should be timely and courteous regarding pre-analytical factors influencing laboratory test results (eg, incomplete submission forms, inappropriate sample or sample handling or poor sample quality). Clients should be informed of the expected time for receipt of preliminary and final reports.
G. Personnel Safety
Personal protective equipment should be appropriate for handling specimens and equipment used for RIA. Safety procedures and disposal of all samples and supplies should be appropriate for the type of specimen. Personnel should receive safety and biohazard training and information about exposure to potentially hazardous chemicals or infectious agents. All training should be documented.
H. Laboratory Environment
The laboratory space should be clean, well lit, and organized to ensure proper achievement of the above goals.
I. Personnel Requirements
Laboratory personnel should have training in specimen handling and sample preparation. Documentation of training, continuing education and periodic proficiency assessment should be at the discretion of the laboratory director.
II. Analytical Factors Important in RIA [Return to Top]
A. Validation (Return to Top)
1. Any radioimmunoassay should be validated for the species for which it will be used. Validation should include either a or b:
(a) Articles in refereed veterinary journals for the particular test (if available). It is not good practice to rely on the manufacturer’s testing alone. The test should be validated independently.
(b) If the test cannot be substantiated through independent validation, then the following minimum evaluation is necessary:
- Run-to-run precision - minimum of 10 data points
- Within-run precision - minimum of 10 data points
- Recovery procedures - use a purified natural substance for each species, where possible. Recovery should be performed using both high end and low concentration samples
- Evaluation of interfering substances such as hemolysis, lipemia, bilirubinemia, medication interactions, etc.
- Parallelism - dilutions and details of linearity.
- A minimum of 30 animals that are considered "normal" for the analyte should be evaluated for each species. Clinical assessment of efficacy also is required by study of diseased individuals.
- Standard curves are needed for each test. Some gamma counters can store curves. If this is implemented in routine testing, validation of the procedure should be present.
B. Documentation (Return to Top)
1. Procedure manual - A detailed procedure manual must be in place for each test performed and should include the following:
(a) Title
(b) Principle of the test, including calculations
(c) Significance of the test
(d) Specimen requirements
(e) Interfering substances. Information may be obtained from the manufacturer, refereed journals or from in-house evaluation.
(f) Reagents and supplies. A list of supplies required, including syringes and consumables.
(g) Equipment used, including the type of gamma counter, whom to call with problems and where the log is located with details on calibrations.
(h) Procedures with sufficient detail so anyone with technical knowledge can easily follow them and perform the test.
(i) Acceptable limits for test accuracy and dilution procedures for results outside of reportable range.
(j) Reference values for all species tested
(k) General comments. These may include an in-house check list for troubleshooting and problems.
(l) Dates that all procedures were instituted, amended, or discontinued
2. All manuals (past and present) are to be stored within the laboratory for reference by the clinical pathologist or laboratory technicians.
C. Quality Control (Return to Top)
1. A minimum of 3 control materials should be assayed with each test. These can include commercial controls for high, normal and low values or samples developed in-house.
2. Interpretation of RIA results often depends on methodology and on reference values established in-house, making it difficult to use some types of external control systems. It is recommended that when using external control materials that in-house materials also be analyzed and interpretation compared.
3. External controls should be used and plotted at least quarterly.
4. All control material results should be recorded and plots and values should be readily accessible to personnel running the tests. Levy-Jennings plots are acceptable.
5. An action plan must be in place that details acceptance or rejection of patient test results based on control values.
6. If the procedure, as detailed by the manufacturer or published articles is modified (ie, only 1 tube per patient), documentation should be available to show that test precision and accuracy are still acceptable with the modification(s).
Postanalytical Factors Important in RIA [Return to Top]
A. Computer Entry of Data/Transcription
Reports should be accurate whether created manually or by transcription, and in a standard format as established by the laboratory. Established laboratory standards for uniform reporting should be met.
B. Report Generation
Reports should be in a format that is readable and easily understood, with appropriate references or explanations as needed. They should be generated in a timely manner relative to preanalytical and analytical components.
C. Report Delivery
Report delivery should be timely, to the correct client, and in a manner agreed upon by the client and the laboratory.
D. Specimen Storage
Specimens should be stored under appropriate conditions for a predetermined time period, as determined by specimen stability, laboratory policy and/or certification/accreditation requirements.
E. Specimen Disposal
Laboratories should appropriately dispose of biohazardous and non-biohazardous materials and specimens, including timely emptying of all containers and trash bins.
F. Personnel Safety
Conditions should be appropriate for computer entry, transcription, handling of specimens, specimen disposal and all other postanalytical tasks.
G. Laboratory Environment
Laboratory environment should meet standard requirements necessary for safe, rapid, efficient and effective performance.
H. Personnel Requirements
Personnel should meet training requirements as indicated for specific areas of the laboratory.