In Vitro Diagnostic Sodium Test System; Final Guidance for Industry

Document issued on: July 6, 1998

U.S. Department Of Health And Human Services Food and Drug Administration Center for Devices and Radiological Health Chemistry Toxicology and Hematology Branch Division of Clinical Laboratory Devices Office of Device Evaluation

Preface

Public Comment

Comments and suggestions may be submitted at any time for Agency consideration to, Joseph L. Hackett, Ph.D., Division of Clinical Laboratory Devices, HFZ-440, 9200 Corporate Blvd, Rockville, MD 20850. Comments may not be acted upon by the Agency until the document is next revised or updated. For questions regarding the use or interpretation of this guidance contact Joseph L. Hackett, Ph.D., at 301 594-3084.

Additional Copies

Additional copies are available from the Internet. You may also send an e-mail request to dsmica@fda.hhs.gov to receive an electronic copy of the guidance or send a fax request to 301-827-8149 to receive a hard copy. Please use the document number (1109) to identify the guidance you are requesting.

Guidance Document

Device: In Vitro Diagnostic Sodium Test System

1. Device Description

   Common Name (s): Sodium Test System

   Class: II

   Classification Panel: Clinical Chemistry (75)

   Product Codes:

   JGT, Flame Photometry, Sodium
   JGS, Ion Specific Electrode, Sodium
   CEI, Uranyl Acetate/Zinc Acetate, Sodium

   Regulation numbers,: 21 CFR 862.1665

   A sodium test system is a device intended to measure sodium quantitatively in serum, plasma, and urine.

2. Indications for Use

   Measurements obtained by this device are used in the diagnosis and treatment of aldosteronism (excessive secretion of the hormone aldosterone), diabetes insipidus (chronic excretion of large amounts of dilute urine, accompanied by extreme thirst), adrenal hypertension, Addison's disease (caused by destruction of the adrenal glands), dehydration, inappropriate antidiuretic hormone secretion, or other diseases involving electrolyte imbalance.

   The intended patient population may be adult, pediatric, and neonatal, while the environment of use may be a hospital (e.g., respiratory care or laboratory department), urgent care situations (e.g., intensive care unit, surgery, emergency department), or bedside/near patient care situations.

3. Specific Performance Characteristics

   1. PreClinical/Laboratory/In Vitro Studies

      The following eight performance characteristics (#1 Method Comparison - #8 Expected Values) should be included in the submission. Data should be provided that supports the use of the device with the specimen type(s) that are claimed to be appropriate for analysis:

      1. Method Comparison
         -slope, intercept
         -correlation coefficient
         -range of samples tested
         - standard error of the estimate
         -bias and bias plot
         -number of samples tested
         -plot of the data
      2. Precision
         -within-run (assay, and
         -between-run (assay), or
         -total
         -mean(s), standard deviation (s), and coefficient(s) of variation
      3. Linearity
         -recovery, dilution, etc.
      4. Sensitivity
         -minimum detection limit, or
         -analytical sensitivity
      5. Interferences
         -endogenous, e.g., bilirubin, hemoglobin, lipids, etc.
         -exogenous, e.g., drugs, anticoagulants, etc.
      6. Stability Summary
         -calibration interval
         -quality control interval
         -quality control materials
         -calibration materials
      7. Software -validation information
         -certification information
      8. Expected Values -literature reference (s), reference interval, or
         -population study, reference interval,
         -medical decision point(s) and/or
         -critical decision point(s)

   2. Clinical Studies

      A method comparison study as described above, comparing performance with that of the predicate device as well as an appropriate reference method should be conducted to demonstrate substantial equivalence. A statistically significant sample of patients from a population representing the proposed intended use should be included in the study, spanning the appropriate assay range.

   3. Total Measurement Error at selected decision points should be calculated and reported.

4. Labeling Considerations:

   Refer to 21 CFR 809.10. Other: For a multi-purpose instrument used for diagnostic purposes refer to 21 CFR 809.10 (b) (1),(2),(6),(14),and (15).

   Checklist

   Instructions: Use this checklist for premarket notification for Sodium Test System as a guide in preparing your submission.

   Truthful and Accurate statement verbatim as per 21 CFR 807.87(j).
   510(k) summary or statement per 21 CFR 807.92 or 21 CFR 807.93 respectively.
   Indications for use on a separate page.
   Labeling for in vitro diagnostic products (21 CFR 809.10 (b)
   Pre-Clinical Data:
   Interference Studies
   Linearity Studies
   Precision studies at medical decision levels
   Clinical Data (method comparison)

REFERENCES:

Methodologies to assist sponsors in establishing the specific performance characteristics addressed in part III of this document may be obtained using NCCLS documents or one of the following references:

Carey RN and Garber CC: Evaluation of Methods in Clinical Chemistry - theory, analysis, and correlation; Kaplan LA and Pesce AJ (eds), CV Mosby Company, St. Louis, 1984.

Koch DD and Peters T: Selection and Evaluation of Methods in Tietz Textbook of Clinical Chemistry (Burtis CA and Ashwood ER, WKB Saunders Co, Philadelphia, 1994.