The Vitamin D 200M Assay for the Topaz System is intended for in vitro diagnostic use in the quantitative determination of total 25-hydroxyvitamin D (25-OH-D) through the measurement of 25-hydroxyvitamin D3 (25-OH-D3) and 25-hydroxyvitamin D2 (25-OH-D2) in human serum using LC-MS/MS technology by a trained laboratory professional in a clinical laboratory. The Assay is intended for use with the Topaz System. The Vitamin D 200M Assay for the Topaz System is intended to be used in conjunction with other clinical or laboratory data to assist the clinician in making individual patient management decisions in an adult population in the assessment of vitamin D sufficiency.

Device Description

The Vitamin D 200M Assay for the Topaz System employs LC-MS/MS technology (Topaz System) in conjunction with reagents and sample preparation components to extract, separate by chromatography, detect, and quantify total Vitamin in human serum.

The Topaz System is a liquid chromatography-tandem mass spectrometry (LC-MS/MS) system intended to for use in a clinical laboratory environment to identify inorganic or organic compounds in human specimens by ionizing the compound under investigation and separating the resulting ions by means of an electrical and magnetic field according to their mass.

Each assay kit contains enough material for 1000 tests, and includes reagents, sample extraction and purification components, calibrators, controls and the Vitamin D 200M Assay specific file which contains all necessary parameters to process the assay.

AI/ML Overview

This document describes the process by which a medical device, the Vitamin D 200M Assay for the Topaz System, received automatic Class III designation. The device is intended for quantitative determination of total 25-hydroxyvitamin D (25-OH-D) to assist clinicians in assessing vitamin D sufficiency.

Here's a breakdown of the acceptance criteria and the study proving the device meets them:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are derived from the special controls defined in 21 CFR 862.1840 for Total 25-hydroxyvitamin D Mass Spectrometry Test Systems. The reported device performance is extracted from the "Performance Characteristics" section of the document.

Acceptance Criteria (from 21 CFR 862.1840 Special Controls)	Reported Device Performance
(1) The device must have initial and annual standardization verification by a certifying vitamin D standardization organization deemed acceptable by FDA.	Traceability: The assigned 25-hydroxyvitamin D of the Vitamin D 200M Assay for the Topaz System is certified with the CDC Vitamin D Standardization-Certification Program (VDSCP). (Source: CDC website link provided, last accessed May 18, 2017).
(2) The 21 CFR 809.10(b) compliant labeling must include detailed descriptions of performance testing conducted to evaluate precision, accuracy, linearity, interference, including the following:	Detailed descriptions are provided in the "L. Performance Characteristics" section and other sections of the document.
(i) Performance testing of device precision must, at a minimum, use intended sample type with Vitamin D concentrations at medically relevant decision points. At least one sample in the precision studies must be an unmodified patient sample. This testing must evaluate repeatability and reproducibility using a protocol from an FDA-recognized standard.	Reproducibility/Precision: Data was analyzed according to the multi-site evaluation study outlined in CLSI EP05-A3 guideline. The study was performed at three sites. Five serum samples were assayed on five calendar days, with one run per day and five replicates per sample. The analyte concentrations of the samples approximated both low and high levels, as well as medical decision points. The sixth sample was a native patient sample (unmodified).
(ii) Performance testing of device accuracy must include a minimum of 115 serum or plasma samples that span the measuring interval of the device and compare results of the new device to results of a reference method or a legally marketed standardized mass spectrometry based vitamin D assay. The results must be described in the 21 CFR 809.10(b)(12) compliant labeling of the device.	Method comparison with reference method: The sponsor performed an accuracy study to the CDC Vitamin D Standardization-Certification Program (VDSCP). The sample set contained 118 unique natural patient serum samples which were purchased and value assigned by CDC with total 25-OH-vitamin D concentrations ranging from 5.6 ng/mL to 133 ng/mL. Twelve specimens were contrived (10.2%). The comparison data was analyzed to find the Pearson correlation coefficient and an estimate of the bias using the slope of the line from the Passing-Bablok fit.
(iii) Interference from vitamin D analogs and metabolites including vitamin D2, vitamin D3, 1-hydroxyvitamin D2, 1-hydroxyvitamin D3, 3-Epi-25-Hydroxyvitamin D2, 3-Epi-25-Hydroxyvitamin D3, 1,25-Dihydroxyvitamin D2, 1,25-Dihydroxyvitamin D3, 3-Epi-1,25-Dihydroxyvitamin D2, and 3-Epi-1,25-Dihydroxyvitamin D3, 25, 26-Dihydroxyvitamin-D3, 24 (R), 25-dihydroxyvitamin-D3, 23 (R), 25-dihydroxyvitamin-D3 must be described in the 21 CFR 809.10(b)(7) compliant labeling of the device.	Analytical specificity: The design of the analytical specificity study was based on CLSI EP07-A2 guideline. A total of 79 potential interferents, at high and low concentrations, were spiked into samples with high and low concentrations of analyte (~37 ng/mL and ~11 ng/mL). Each of the four concentration combinations was tested in triplicate: low analyte/low interferent, low analyte/high interferent, high analyte/low interferent, and high analyte/high interferent, and was compared to control samples spiked with solvent instead of interferent. None of the potential endogenous and exogenous interfering substances or collection tubes tested in this study was found to cause interference with the analyte of interest greater than a 10% difference between the test and control samples. A comprehensive table listing substances and their highest concentration tested without significant interference is provided in the document. This list includes the specific vitamin D analogs and metabolites mentioned in the acceptance criteria.
(3) The 21 CFR 809.10(b) compliant labeling must be supported by a reference range study representative of the performance of the device. The study must be conducted using samples collected from apparently healthy male and female adults at least 21 years of age and older from at least 3 distinct climatic regions within the United States of America in different weather seasons. The ethnic, racial, and gender background of this study population must be representative of the US population demographics.	Expected Values: A reference range study was conducted with reference to the CLSI EP28-A3 guideline. A total of 404 serum samples from apparently healthy male and female adults 21 years of age and older from 3 different geographic regions were analyzed. The inner 95% Reference interval of 25(OH) vitamin D concentrations found in this population was 8.6 to 49 ng/mL. (Note: The document states "3 different geographic regions" which addresses the "distinct climatic regions" without explicitly stating "United States of America" or "different weather seasons". It also does not explicitly detail the "ethnic, racial, and gender background" as being "representative of the US population demographics" within this specific section, though it is a general requirement for such studies).
(4) The results of the device as provided in the 21 CFR 809.10(b) compliant labeling and any test report generated must be reported as only total 25-hydroxyvitamin D.	Indications For Use: The assay is intended for in vitro diagnostic use in the quantitative determination of total 25-hydroxyvitamin D (25-OH-D) through the measurement of 25-hydroxyvitamin D3 (25-OH-D3) and 25-hydroxyvitamin D2 (25-OH-D2). Test Principle: "Total Vitamin D concentrations is calculated as a total of the concentrations of 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2." This directly supports reporting only total 25-hydroxyvitamin D.
Linearity/Assay Reportable Range:	A linearity study was performed according to CLSI EP06-A to assess the linearity of the Vitamin D 200M Assay across the assay measuring range (4 to 140 ng/mL). The results of the linear regression analyses were: y = 0.9974x + 1.1737 R2 = 0.9984. The linearity study data support the claimed measuring range of 4.0 to 140 ng/mL.
Detection Limit:	The lower limit of the measuring interval (LLMI) for this assay was determined to be 2.9 ng/mL for total 25-OH-Vitamin D. This was determined as the lowest concentration of analyte that achieved both the bias and precision goals (<20% bias and <20% CV).
Carryover:	Studies were performed at a single internal site using 3 instruments and 3 kit lots over a period of 1 day. There was no carry-over demonstrated in the study. This study was sufficient to demonstrate that there was no significant carry-over.

2. Sample Size Used for the Test Set and Data Provenance

Test Set Sample Size:
- Precision/Reproducibility: 6 serum samples (5 spiked/diluted, 1 native patient). Each sample was assayed on 5 calendar days, with 1 run per day and 5 replicates per sample.
- Linearity: 9 serum samples (serially diluted from a high concentration sample).
- Accuracy/Method Comparison: 118 unique natural patient serum samples. 12 specimens (10.2%) were contrived.
- Analytical Specificity/Interference: 79 potential interferents, spiked into samples with high and low analyte concentrations. Each of four concentration combinations was tested in triplicate.
- Reference Range Study: 404 serum samples.
Data Provenance: The document does not explicitly state the country of origin for all data.
- For the Accuracy/Method Comparison, the samples were "purchased and value assigned by CDC" and "CDC Vitamin D Standardization-Certification Program (VDSCP)," which implies US-based reference and potentially US-derived samples.
- For the Reference Range Study, samples were from "3 different geographic regions" and are described in the context of being "representative of the US population demographics," strongly implying US-based retrospective or prospective collection.
- The Precision study was "performed at three sites," which could be internal or external but is not specified beyond that.
- All studies appear to be prospective in nature, as they are described as "studies performed" or "study was performed" to evaluate the device's characteristics.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

This device is an in vitro diagnostic (IVD) assay for quantitative measurement, not an image-based AI device requiring expert human readers for ground truth.

Ground Truth for Accuracy/Method Comparison: The ground truth for the 118 patient samples was established by the CDC Vitamin D Standardization-Certification Program (VDSCP), which acts as a reference method. The specific "experts" or their qualifications within the CDC program are not detailed in this document, but their role as a "standardization organization" implies high-level analytical expertise.
For other analytical performance characteristics (precision, linearity, detection limit, analytical specificity), the ground truth is based on the known concentrations of spiked analytes or the intrinsic properties of the samples used, not on expert human interpretation.

4. Adjudication Method for the Test Set

Not applicable in the context of a quantitative IVD device. Ground truth for the method comparison was established by a reference method (CDC VDSCP), not through human adjudication of differing interpretations. Analytical performance studies rely on measured values against known concentrations or statistical methods defined by CLSI guidelines.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, If So, What Was the Effect Size of How Much Human Readers Improve with AI vs Without AI Assistance

Not applicable. This is an in vitro diagnostic (IVD) assay, not an AI-assisted diagnostic imaging device that involves human reader interpretation. No MRMC study was performed.

6. If a Standalone (i.e., Algorithm Only Without Human-in-the-Loop Performance) Was Done

Yes, the entire performance characterization described in the document is for the standalone device (the Vitamin D 200M Assay on the Topaz System) without human-in-the-loop performance influencing the measurement itself. The device performs the LC-MS/MS analysis and provides a quantitative result. Human involvement is primarily in operating the system, preparing samples, and using the results in conjunction with other clinical data. The performance metrics (precision, accuracy, linearity, etc.) are solely for the device's technical capabilities.

7. The Type of Ground Truth Used

Accuracy/Method Comparison: The ground truth was established by a reference method (CDC Vitamin D Standardization-Certification Program (VDSCP)). This is equivalent to an external, highly standardized, and validated method.
Precision, Linearity, Detection Limit, Analytical Specificity: Ground truth was based on the known concentrations of analytes in prepared samples (spiked or diluted samples) or intrinsic properties of native samples, following established CLSI guidelines. This falls under a form of "designed experimental data with known parameters."
Reference Range Study: Ground truth for this was the actual measured 25-OH-D concentrations in the serum samples of "apparently healthy" individuals, which were then used to define the expected reference interval. This is based on outcomes data in a healthy population.

8. The Sample Size for the Training Set

Not applicable. This document describes an IVD assay, not a machine learning or AI-based device that requires a distinct "training set" in the computational sense. The device's underlying principles are based on LC-MS/MS technology and established chemical/physical properties, not on training a model with data.

9. How the Ground Truth for the Training Set Was Established

Not applicable, as there is no "training set" for this type of device.

Summary

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EVALUATION OF AUTOMATIC CLASS III DESIGNATION FOR Vitamin D 200M Assay

DECISION SUMMARY

A. DEN Number:

DEN170019

B. Purpose for Submission:

De Novo request for evaluation of automatic class III designation for the Vitamin D 200M Assay for the Topaz System

C. Measurand:

Total 25-hydroxyvitamin D

D. Type of Test:

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

E. Applicant:

AB SCIEX

F. Proprietary and Established Names:

Vitamin D 200M Assay

G. Regulatory Information:

1. Regulation:
  21 CFR 862.1840
1. Classification:
  Class II (special controls)
1. Product code(s):
  PSL

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1. Panel:
  Clinical Chemistry (75)

H. Indications For Use:

1. Indications for Use:
  The Vitamin D 200M Assay for the Topaz System is intended for in vitro diagnostic use in the quantitative determination of total 25-hydroxyvitamin D (25-OH-D) through the measurement of 25-hydroxyvitamin D3 (25-OH-D3) and 25-hydroxyvitamin D2 (25-OH-D2) in human serum using LC-MS/MS technology by a trained laboratory professional in a clinical laboratory. The Assay is intended for use with the Topaz System. The Vitamin D 200M Assay for the Topaz System is intended to be used in conjunction with other clinical or laboratory data to assist the clinician in making individual patient management decisions in an adult population in the assessment of vitamin D sufficiency.
1. Special conditions for use statement(s):
  For in vitro diagnostic use only. For prescription use only.
1. Special instrument requirements:
  Topaz System

I. Device Description:

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The assay contains calibrators to calibrate the Vitamin D 200M Assay for the Topaz System. The matrix base of the calibrators is human serum. Human source material is tested for the presence of antibodies to Human Immunodeficiency Virus Type 1 (HIV-1) and Type 2 (HIV-2), Hepatitis B Surface Antigen and antibodies to Hepatitis C Virus (HCV) and found to be negative/non-reactive.

J. Standard/Guidance Documents Referenced:

CLSI EP25-A Evaluation of Stability of In Vitro Diagnostic Reagents

CLSI EP28-A3c Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory

CLSI EP17-A2 Evaluation of Detection Capability for Clinical Laboratory Measurement Procedures

CLSI EP9-A3 Measurement Procedure Comparison and Bias Estimation Using Patient Samples

CLSI EP07-A2 Interference Testing in Clinical Chemistry

CLSI EP06-A Evaluation of the Linearity of the Quantitative Measurement Procedures: A Statistical Approach

CLSI EP05-A3 Evaluation of Precision Performance of Quantitative Measurement Methods

CLSI C62-A Liquid Chromatography-Mass Spectrometry Methods

IEC 61010-1:2001 IEC Safety Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use - Part 1: General Requirements

IEC 61010-2-101:2002 IEC Safety Requirements for Electrical Equipment for Measurement, Control. and Laboratory Use - Part 2-101: Particular Requirements for In Vitro Diagnostic (IVD) Medical Equipment

IEC 61010-2-061: 2005 IEC Safety Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use - Part 2-061: Particular Requirements for Laboratory Atomic Spectrometers with Thermal Atomization and Ionization 2005 8-28

K. Test Principle:

The Vitamin D 200M Assay for the Topaz System employs LC-MS/MS technology in conjunction with reagents and sample preparation components to extract, separate by chromatography, detect and quantify total Vitamin D in human serum.

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During the sample preparation stage, an isotopic 25-hydroxyvitamin D3 analog is used as an internal standard and is added to the sample. The analytes of interest are extracted from the sample matrix by protein precipitation and centrifugation.

Analyte separation, ionization, detection, and quantitation and reporting are achieved through LC-MS/MS technology on the Topaz System. The liquid chromatography (LC) component of the Topaz System separates chemicals by conventional chromatography on a column. The analyte separation method is reverse phase chromatography, where the analytes bind to the chromatography column by hydrophobic interactions in the presence of a hydrophilic solvent (for instance water) and are eluted off by a more hydrophobic solvent (methanol or acetonitrile). As the analytes elute from the end of the column they enter the mass spectrometer, where the solvent is removed and the analytes are ionized. The analytes must be ionized as the mass spectrometer can only detect ions. not neutral molecules. The mass spectrometer then scans the analytes of interest by mass and produces a full high-resolution spectrum, separating all ions that have different masses. The ions can be further fragmented to produce daughter ions (MS/MS). Monitoring the transitions of the original (parent) and daughter ions provides a highly specific identification of the desired analytes.

The parent ions of 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 and major fragment ions are monitored and detected in the mass spectrometer. The concentration of 25hydroxyvitamin D3 and 25-hydroxyvitamin D2 is interpolated from a calibration curve established with calibrators of known standard concentrations. Total Vitamin D concentrations is calculated as a total of the concentrations of 25-hydroxyvitamin D3 and 25hydroxyvitamin D2.

L. Performance Characteristics:

1. Analytical performance:
a. Reproducibility/Precision:

Data was analyzed according to the multi-site evaluation study outlined in CLSI EP05-A3 guideline. The study was performed at three sites. Five serum samples were assayed on five calendar days, with one run per day and five replicates per sample. The analyte concentrations of the samples approximated both low (b) (4) and high (0) (4) levels, as well as medical decision points. The samples were either diluted with serum that did not contain vitamin D or spiked with 25-OH-vitamin D standards to achieve the low and high concentrations. The sixth sample was a native patient sample (unmodified).

Results obtained are summarized below:

Sample	Mean	Repeatability		Within-Laboratory		Reproducibility
	(ng/mL)	SD	%CV	SD	%CV	SD	%CV
1	14.9	0.57	3.8%	1.05	7.0%	1.10	7.3%
2	13.7	0.65	4.7%	0.80	5.8%	0.80	5.8%

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Sample	Mean(ng/mL)	Repeatability		Within-Laboratory		Reproducibility
		SD	%CV	SD	%CV	SD	%CV
3	31.0	1.28	4.1%	2.03	6.5%	2.03	6.5%
4	67.5	3.58	5.3%	3.99	5.9%	5.85	8.7%
5	100	6.37	6.3%	6.46	6.4%	10.4	10.4%
NativePatientSample	28.4	1.44	5.1%	2.04	7.2%	2.10	7.4%

b. Linearity/assay reportable range:

A linearity study was performed according to CLSI EP06-A to assess the linearity of the Vitamin D 200M Assay across the assay measuring range (4 to 140 ng/mL). A serum sample with a high concentration of vitamin D was serially diluted with a low concentration serum sample to generate nine samples with vitamin D concentration values of 3.4. 47.7, 91.9, 136, 180, 225, 269, 313, 357 ng/mL, respectively.

The results of the linear regression analyses are summarized below:

y = 0.9974x + 1.1737 R2 = 0.9984

The linearity study data support the claimed measuring range of 4.0 to 140 ng/mL.

Traceability, Stability, Expected values: C.

Traceability:

The assigned 25-hydroxyvitamin D of the Vitamin D 200M Assay for the Topaz System is certified with the CDC Vitamin D Standardization-Certification Program (VDSCP). See VDSCP website for current certification at https://www.cdc.gov/labstandards/hs_standardization.html (last accessed on May 18, 2017; Note this website is not controlled by FDA).

Stability:

Unopened reagents are stable until the expiry date stipulated on the label, provided that the storage conditions indicated on the label are complied with.

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d. Detection limit:

Low level determinations were made for each of six samples that were prepared using two kits from different lots. The lower limit of the measuring interval (LLMI) for each lot was determined to be the lowest concentration of analyte that achieved both the bias and precision goals (<20% bias and <20% CV). The maximum LLMI values from the two lots were set as the values for the method. The LLMI for this assay was determined to be 2.9 ng/mL for total 25-OH-Vitamin D.

f. Analytical specificity:
The design of the analytical specificity study was based on CLSI EP07-A2 guideline. A total of 79 potential interferents, at high and low concentrations, were spiked into samples with high and low concentrations of analyte (~37 ng/mL and ~11 ng/mL). Each of the four concentration combinations was tested in triplicate: low analyte/low interferent, low analyte/high interferent, high analyte/low interferent, and high analyte/high interferent, and was compared to control samples spiked with solvent instead of interferent. None of the potential endogenous and exogenous interfering substances or collection tubes tested in this study was found to cause interference with the analyte of interest greater than a 10% difference between the test and control samples.

Substances	Highest Concentration testedthat did not demonstratesignificant interference
Vitamin-D2	750 ng/mL
Vitamin-D3	750 ng/mL
1-Hydroxyvitamin-D2	750 ng/mL
1-Hydroxyvitamin-D3	750 ng/mL
3-Epi-25-hydroxyvitamin-D2	100 ng/mL
3-Epi-25-hydroxyvitamin-D3	100 ng/mL
1, 24 (R)-dihydroxyvitamin-D3	750 ng/mL
1, 25-Dihydroxyvitamin-D2	10000 pg/mL
1, 25-Dihydroxyvitamin-D3	10000 pg/mL
3-Epi-1, 25-dihydroxyvitamin-D2	10 ng/mL
3-Epi-1, 25-dihydroxyvitamin-D3	10 ng/mL
23 (R), 25-dihydroxyvitamin-D3	10 ng/mL
24 (R), 25-dihydroxyvitamin-D3	150 ng/mL
25, 26-Dihydroxyvitamin-D3	10 ng/mL
Cholesterol	500 mg/dL
Cholesterol, 7-oxo-	68.1 ng/mL
7-Dehydrocholesterol	250 ng/mL
Substances	Highest Concentration testedthat did not demonstratesignificant interference
25-Hydroxycholesterol (25-OHC)	100 ng/mL
7a-Hydroxy-4-cholesten-3-one (7aC4)	200 ng/mL
7a,27-Dihydroxycholesterol	1470 pg/mL
Dehydrocholic acid	147 µg/mL
Calcipotriene (Dovenex)	750 ng/mL
Dihydrotachysterol (drug)	750 ng/mL
Maxacalcitol	750 ng/mL
Paracalcitol (Zemplar)	750 ng/mL
Taurocholic acid	9.28 ng/mL
Biocytin	3.73 ng/mL
Coenzyme A	38.4 mg/L
B-D-Glucose	990 mg/dL
Ascorbic acid	5 mg/dL
Bilirubin (unconjugated)	20 mg/dL
Biotin	1000 ng/mL
Hemoglobin	500 mg/dL
Human Serum Albumin	6 g/dL
IgG	6000 mg/dL
Triglyceride standards	600 mg/dL
Uric acid	20 mg/dL
2'-Deoxyadenosine-5'-triphosphate	982 ng/mL
2'-Deoxycytidine 5'-triphosphate	934 ng/mL
2'-Deoxyguanosine 5'-triphosphate	1010 ng/mL
2'-Deoxyuridine 5'-triphosphate	936 ng/mL
Adenosine 5'-triphosphate	1010 ng/mL
Cytidine 5'-triphosphate	966 ng/mL
Guanosine 5'-triphosphate	1050 ng/mL
Uridine 5'-triphosphate	968 ng/mL
ẞ-Nicotinamide adenine dinucleotide phosphate (NADP)	743 ng/mL
Aminopterin	749 ng/mL
Benazepril	20.4 µg/mL
Bimatoprost isopropyl ester	732 ng/mL
Bradykinin	1800 ng/mL
Bromocriptine	1110 ng/mL
Budesonide	732 ng/mL
Calcipotriol	701 ng/mL
Cefotaxime	307 µg/mL
Cephalothin	301 µg/mL
Cetirizine	2990 ng/mL
Substances	Highest Concentration testedthat did not demonstratesignificant interference
Clindamycin	723 ng/mL
Dexamethasone phosphate	709 ng/mL
Etoposide	1000 ng/mL
Flurazepam	659 ng/mL
Fluticasone propionate	851 ng/mL
Fusidic acid	878 ng/mL
Isradipine	631 ng/mL
Latanoprost	735 ng/mL
Loratadine	299 ng/mL
Mifepristone	730 ng/mL
Minocycline	778 ng/mL
Nimodipine	711 ng/mL
Nisoldipine	660 ng/mL
10(S),17(S)-DiHDoHE (Protectin DX)	3610 ng/mL
Raltitrexed	779 ng/mL
Rescinnamine	1080 ng/mL
Reserpine	1030 ng/mL
Tadalafil	662 ng/mL
Tafluprost	769 ng/mL
Trandolapril	732 ng/mL
Treprostinil	664 ng/mL
Triamcinolone	670 ng/mL
Zopiclone	661 ng/mL

The table below lists all substances tested at concentrations with non-significant (<10%) interference as defined by the sponsor, when compared to the control sample.

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2. Comparison studies:

a. Method comparison with reference method:

The sponsor performed an accuracy study to the CDC Vitamin D Standardization-Certification Program (VDSCP). The sample set contained 118 unique natural patient serum samples which were purchased and value assigned by CDC with total 25-OHvitamin D concentrations ranging from 5.6 ng/mL to 133 ng/mL. Twelve specimens were contrived (10.2%).

The comparison data was analyzed to find the Pearson correlation coefficient and an estimate of the bias using the slope of the line from the Passing-Bablok fit.

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	Passing-Bablok regression results
n	118
Slope	1.008
Intercept	-0.3949
Correlation Coefficient	0.991
Range (ng/mL)	5.6 – 133 ng/mL

b. Matrix comparison:
Not applicable.
1. Clinical studies:
  Not Applicable.
1. Expected Values
  A reference range study was conducted with reference to the CLSI EP28-A3 guideline. A total of 404 serum samples from apparently healthy male and female adults 21 years of age and older from 3 different geographic regions were analyzed. The inner 95% Reference interval of 25(OH) vitamin D concentrations found in this population was 8.6 to 49 ng/mL.

M. Instrument Name:

Topaz System

N. System Description:

1. Modes of Operation:
  Does the applicant's device contain the ability to transmit data to a computer, webserver, or mobile device? Yes _ X

Does the applicant's device transmit data to a computer, webserver, or mobile device using wireless transmission: Yes __or No _ X _ _ .

1. Software:
  FDA has reviewed applicant's Hazard Analysis and software development processes for this line of product types:

Yes_X__or No _________________________________________________________________________________________________________________________________________________________________

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1. Specimen Identification:
  Samples are given a unique identifier.

4. Specimen Sampling and Handling:

Human serum, in liquid form, is the only type of sample that should be used in this assay. Collect samples in clot-activating collection tubes with red tops (or closures).

1. Calibration:
  The 4 calibrators are run with each cartridge. The device software calculates a slope, intercept and R= by linear regression for every run. If the calibration for a run is flagged as "failed" no activity values are reported for the entire run and the entire run must be repeated.
1. Quality Control:
  It is expected that a clinical laboratory using the Topaz System adheres to procedures that cover issues such as, but not limited to, operator training, assay development and validation, and external audits of laboratory assay performance.

O. Other Supportive Instrument Performance Characteristics Data Not Covered In the "Performance Characteristics" Section above:

Carryover:

Studies were performed to determine if the level of carryover for the assay is acceptable. Samples with high and low concentrations of analyte were injected in a predetermined order to determine if the carryover was acceptable. Studies were performed at a single internal site using 3 instruments and 3 kit lots over a period of 1 day. There was no carry-over demonstrated in the study. This study was sufficient to demonstrate that there was no significant carry-over.

Electrical Safety and Electromagnetic Compatibility (EMC):

Electrical safety and EMC testing were conducted on the Topaz System. The system complies with IEC 61010-1 and IEC 61010-2-040 standards for safety and IEC 61326 for EMC.

P. Proposed Labeling:

The labeling is sufficient and satisfies the requirements of 21 CFR Parts 801 and 809, as applicable, and the special controls for this type of device.

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Q. Patient Perspectives:

This submission did not include specific information on patient perspectives for this device.

R. Identified Risks to Health and Identified Mitigations:

Identified Risks to Health	Identified Mitigations
Clinical action based on falsely elevatedinaccurate Vitamin D results may lead tounnecessary supplementation of Vitamin D	General controls and special controls (1)and (2)
Clinical action based on falsely low inaccurateVitamin D results may lead to a delay insupplementation of Vitamin D	General controls and special controls (1)and (2)
Clinical action based on uninterpretable resultsdue to lack of established device specificreference range values for the representativepopulation	General controls and special controls (3)
Clinical action based on the misinterpretationof Vitamin D2 or Vitamin D3 results as totalVitamin D results	General controls and special controls (4)

S. Benefit/Risk Analysis

Summary
Summary of theBenefit(s)	Adults may potentially benefit from the use of the device forassessment of vitamin D sufficiency. The results of the device,when used in conjunction with other clinical and laboratory data,may assist healthcare providers in making individual managementdecisions related to vitamin D sufficiency. Treatment for vitaminD deficiency may improve clinical complications related to bonefracture risk and osteomalacia. Intervention for potential vitamin Dtoxicity may be helpful in avoiding complications associated withvitamin D toxicity.
	The technological characteristics of this device may reduceconcerns specific to immunoassays, including interference andassay drift. The lack of antibody in this device combined with thetwo-step separation of 25-hydroxy vitamin D2 and 25-hydroxyvitamin D3 by chromatography followed by selection by massincreases the specificity of the assay thereby mitigating concernsfrom structurally similar compounds known to interfere withimmunoassay-based vitamin D assays. In addition, the lack ofreliance on antibody production and maintenance reduces concernsof assay drift over time.
	A patient with a falsely elevated result which crosses a medical decision making threshold may result in a missed opportunity to benefit from vitamin D treatment, and potentially be at risk for complications associated with vitamin D deficiency. The healthcare provider ordering the test may be misled into believing that vitamin D treatment is not necessary based on a vitamin D result that is reported in the "sufficient" or "toxic" range. This scenario is of particular concern in patients who are particularly likely to benefit from treatment with vitamin D, including those patients with osteoporosis, patients at high risk for bone fractures, or patients suffering from osteomalacia. This scenario is also of concern in patients who have an increased risk of vitamin D deficiency including obesity, certain medications that enhance the catabolism of 25(OH)D and 1,25(OH)2D, as well as conditions that increase metabolism of 25(OH)D to 1,25(OH)2D, including chronic granuloma-forming disorders, some lymphomas, and primary hyperparathyroidism.
Summary of the Risk(s)	A patient with a falsely low result which crosses a medical decision making threshold may result in a delay or failure for clinical intervention for potential vitamin D toxicity. The healthcare provider ordering the test may be misled into believing that vitamin D treatment is necessary based on a vitamin D result that is reported in the "deficient" or "sufficient" range. The potential clinical consequences of long-term untreated vitamin D toxicity may be nephrocalcinosis, bone demineralization, and bone pain. This scenario is of particular concern in patients with chronic granuloma-forming disorders (i.e., sarcoidosis or tuberculosis, lymphoma, chronic fungal infections), who may be more sensitive to vitamin D treatment.There is a risk relating to unknown performance of this device outside of the intended use population. Risks relating to utilization outside of the intended use population (i.e., pediatric population) are mitigated by appropriate labeling and requirement for prescription use. Similarly, over-reliance on device results should be mitigated by appropriate labeling and requirement for prescription use.
Summary of OtherFactors	As specified by labelling, a total 25-hydroxy vitamin D level maybe used in conjunction with other clinical or laboratory data toassist healthcare providers in making individual managementdecisions related to vitamin D sufficiency.Further analytical risks are mitigated by labelling and therequirement for professional use.Analytical performance studies were considered as part of thedevice review.
ConclusionsDo the probable benefits outweigh the probable risks?

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Yes. Given the device's indications for use, required general controls and special controls established for this device (e.g., labeling and clinical studies performed), the probable benefits outweigh the probable risks.

T. Conclusion:

The information provided in this de novo submission to classify this device into class II under regulation 21 CFR 862.1840. FDA believes that special controls, along with the applicable general controls, provide reasonable assurance of the safety and effectiveness of the device type. This device is classified under the following:

Product Code:	PSL
Device Type:	Total 25-hydroxyvitamin D Mass Spectrometry Test System
Class:	II (special controls)
Regulation:	21 CFR 862.1840

(a) Identification. A total 25-hydroxyvitamin D mass spectrometry test system is a device intended for use in clinical laboratories for the quantitative determination of total 25hydroxyvitamin D (25-OH-D) in serum or plasma to be used in the assessment of vitamin D sufficiency.

(b) Classification. Class II (special controls). Vitamin D test systems must comply with the following special controls:

(1) The device must have initial and annual standardization verification by a certifying vitamin D standardization organization deemed acceptable by FDA.

(2) The 21 CFR 809.10(b) compliant labeling must include detailed descriptions of performance testing conducted to evaluate precision, accuracy, linearity, interference, including the following:

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(i) Performance testing of device precision must, at a minimum, use intended sample type with Vitamin D concentrations at medically relevant decision points. At least one sample in the precision studies must be an unmodified patient sample. This testing must evaluate repeatability and reproducibility using a protocol from an FDArecognized standard.

(ii) Performance testing of device accuracy must include a minimum of 115 serum or plasma samples that span the measuring interval of the device and compare results of the new device to results of a reference method or a legally marketed standardized mass spectrometry based vitamin D assay. The results must be described in the 21 CFR 809.10(b)(12) compliant labeling of the device.

(iii) Interference from vitamin D analogs and metabolites including vitamin D2, vitamin D3, 1-hydroxyvitamin D2, 1-hydroxyvitamin D3, 3-Epi-25-Hydroxyvitamin D2, 3-Epi-25-Hydroxyvitamin D3, 1,25-Dihydroxyvitamin D2, 1,25-Dihydroxyvitamin D3, 3-Epi-1,25-Dihydroxyvitamin D2, and 3-Epi-1,25-Dihydroxyvitamin D3, 25, 26-Dihydroxyvitamin-D3, 24 (R), 25-dihydroxyvitamin-D3, 23 (R), 25-dihydroxyvitamin-D3 must be described in the 21 CFR 809.10(b)(7) compliant labeling of the device.

(3) The 21 CFR 809.10(b) compliant labeling must be supported by a reference range study representative of the performance of the device. The study must be conducted using samples collected from apparently healthy male and female adults at least 21 years of age and older from at least 3 distinct climatic regions within the United States of America in different weather seasons. The ethnic, racial, and gender background of this study population must be representative of the US population demographics.

(4) The results of the device as provided in the 21 CFR 809.10(b) compliant labeling and any test report generated must be reported as only total 25-hydroxyvitamin D.

Regulation Number and Section

§ 862.1840 Total 25-hydroxyvitamin D mass spectrometry test system.

(a)
Identification. A total 25-hydroxyvitamin D mass spectrometry test system is a device intended for use in clinical laboratories for the quantitative determination of total 25-hydroxyvitamin D (25-OH-D) in serum or plasma to be used in the assessment of vitamin D sufficiency.(b)
Classification. Class II (special controls). The device is exempt from the premarket notification procedures in part 807, subpart E, of this chapter subject to the limitations in § 862.9. The device must comply with the following special controls:(1) The device must have initial and annual standardization verification by a certifying vitamin D standardization organization deemed acceptable by FDA.
(2) The 21 CFR 809.10(b) compliant labeling must include detailed descriptions of performance testing conducted to evaluate precision, accuracy, linearity, interference, including the following:
(i) Performance testing of device precision must, at a minimum, use intended sample type with Vitamin D concentrations at medically relevant decision points. At least one sample in the precision studies must be an unmodified patient sample. This testing must evaluate repeatability and reproducibility using a protocol from an FDA-recognized standard.
(ii) Performance testing of device accuracy must include a minimum of 115 serum or plasma samples that span the measuring interval of the device and compare results of the new device to results of a reference method or a legally marketed standardized mass spectrometry based vitamin D assay. The results must be described in the 21 CFR 809.10(b)(12) compliant labeling of the device.
(iii) Interference from vitamin D analogs and metabolites including vitamin D2, vitamin D3, 1-hydroxyvitamin D2, 1-hydroxyvitamin D3, 3-Epi-25-Hydroxyvitamin D2, 3-Epi-25-Hydroxyvitamin D3, 1,25-Dihydroxyvitamin D2, 1,25-Dihydroxyvitamin D3, 3-Epi-1,25-Dihydroxyvitamin D2, and 3-Epi-1,25-Dihydroxyvitamin D3, 25, 26-Dihydroxyvitamin-D3, 24 (R), 25-dihydroxyvitamin-D3, 23 (R), 25-dihydroxyvitamin-D3 must be described in the 21 CFR 809.10(b)(7) compliant labeling of the device.
(3) The 21 CFR 809.10(b) compliant labeling must be supported by a reference range study representative of the performance of the device. The study must be conducted using samples collected from apparently healthy male and female adults at least 21 years of age and older from at least 3 distinct climatic regions within the United States in different weather seasons. The ethnic, racial, and gender background of this study population must be representative of the U.S. population demographics.
(4) The results of the device as provided in the 21 CFR 809.10(b) compliant labeling and any test report generated must be reported as only total 25-hydroxyvitamin D.