Science & Research

Volume III - 3.4 Types of Analysis

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Other Laboratory Operations
Food and Drug Administration



Section 3 - Recording of Results - Analyst Worksheet



3.4.1 Types

There are different types of analyses that are conducted on samples. The type of analysis required is usually defined in the Compliance Program or Assignment. The types analyses that are addressed in individual Compliance Programs and Assignments include the following:

  • Screening – used to detect the presence of a substance or class of substances at the level of interest and to filter large numbers of samples for potential non-compliant results. Methods used in screening samples are an estimate.
  • Confirmatory – used as a means to provide full or complementary information enabling the substance to be unequivocally identified and if necessary quantified. Methods that provide information the chemical or DNA structure of the analyte or organism are confirmation testing and do not always require a second determinative or check analysis.
  • Determinative analysis – used to determine the presence or concentration of an identified organism or analyte
  • Check Analysis – a separate and different analysis than the original analysis and used to confirm a finding

3.4.2 Check Analysis

The check analysis is performed to confirm a finding. The check analysis is performed by a standard method or FDA "Official" method. When such a procedure is not available, or is unsuitable for the analysis being performed, recovery data will be obtained to support validity of the results.

Requirements for check analyses are discussed below. These are not all-inclusive. There will be circumstances when the check is not required or, conversely, when it is judged necessary on a sample usually exempt from check analysis. Individual compliance programs and Compliance Policy Guides must be consulted for special requirements. When unusual circumstances exist for particular samples. the center(s) must be consulted about the need for check analysis. Check Analysis Required

Check analysis is necessary on violative regulatory samples, both domestic and import, and on violative samples that will be referred to a local, State, or Federal agency and that may form the basis for action by that agency.

Check analysis will be conducted by a second competent and qualified analyst and, when one is available, on a separate, intact portion of the product (e.g. intact food product. intact tablets, unopened vials or bottles of liquid products). In practice, there may be reasons for exceptions to this requirement:

  1. When sample preparation instructions require compositing and comminuting or blending the entire sample (e.g. some pesticide or metal samples), the check analyst will analyze a second portion of the prepared composite. When comminution is not required for the entire composited sample, the check analyst will take a representative portion of the uncomminuted composite and subject it to the required additional preparation.
  2. When program requirements do not provide a FDA reserve portion (e.g. certain medical devices, radiological health samples), where feasible, a second analyst may observe the original analyst's work or duplicate selected segments of the analysis on the same sample.
  3. When the examination is for isolated filth and extraneous material, the check analyst need only examine elements isolated by the original analyst from a sufficient number of sub samples to be assured that the original analyst has reliably identified the elements.
  4. When visual examinations for defective units of foods, drugs, or devices are conducted by an analyst, another analyst (usually one who is more experienced) confirms the defects.
  5. For samples that traditionally do not have separate portions analyzed, such analysis is not truly a check analysis, rather, it is a confirmation of the original results. Such analyses include moisture and fat determinations on dairy product sub samples prepared by the original analyst, mold counts on sub samples prepared by the analyst if no FDA reserve portion is available, or organoleptic examination of sub samples analyzed by the original analyst if no FDA reserve is available and there are no instructions directing analysis of a separate intact portion.

When reagents, standards. and equipment are required in the analysis, the check analysis will be conducted independently of the original analysis. The check analyst must prepare the reagents and standards used, or must demonstrate by reanalysis (e.g. volumetric solution), controls (e.g. media), or other objective evidence that those prepared by others have been prepared properly. When traceable reference standards exist (e.g. National Institute of Standards and Technology (NIST), USP), a reference standard from the current lot(s) must be used in the check analysis. When physical examinations are the issue and the same equipment must be used by the check analyst, the analyst must check the equipment to assure that it is calibrated and operating properly.

Check analysis of a sample may be requested of another district or headquarters laboratory for a specific reason. Reasons for such a request include:

  • availability of an unusually experienced analyst who is familiar with the method or the range of analytical responses exhibited by the commodity;
  • availability of specialized instrumentation; or
  • compliance programs may also state that check examinations are to be performed by specific district or headquarters laboratories. Check Analysis Not Required

Check analysis is not necessary in the following instances:

  1. When certain types of samples are specifically exempted from the requirement for a check analysis by a compliance program or by the Compliance Policy Guides.
  2. When check analysis of specific samples is waived by the center.
  3. When the original analysis is performed by a national or international expert, unless specifically called for by a program or by the Compliance Policy Guides or when the method of analysis, instrumentation, or circumstances require check analysis by other experts. For field laboratories, this decision will be made by the director, Office of Regulatory Science, in consultation with the laboratory director, and the appropriate center compliance unit.
  4. When the original analysis using an standard or FDA "Official" analytical method confirms the result of another government laboratory and personnel from that laboratory will so attest to the results.

The following types of out-of-compliance samples do not require check analysis:

  1. Microbiological samples. Devices for sterility and samples analyzed for antibiotic potency using microbiological techniques do not require check analysis.
  2. Samples originally examined for filth and extraneous material by an analyst recognized as a national or international expert in the particular micro analytical identification. Isolated material must be maintained with the reserve sample.
  3. Exhibits of filth and extraneous material that have been isolated and submitted by the investigator or inspector and confirmed by a qualified analyst.
  4. Samples for net weight determinations when initial weighings have been made by the investigator or inspector and confirmed by a qualified analyst.
  5. Samples proposed for regulatory action on the basis of labeling and the original analysis confirms the label declaration of ingredients.
  6. Samples proposed for regulatory action where the violation is based on the qualitative identification by the laboratory of a prohibited substance which is present at “macro” (i.e. non-trace) level, using a highly-specific method such as mass spectrometry or infrared spectroscopy.

Page Last Updated: 07/14/2015
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