GSP NEONATAL 17A-OH-PROGESTERONE KIT MODEL: 3305-001U

K100682 · Wallac OY · JLX · Jul 23, 2010 · Clinical Chemistry

Device Facts

• Record ID: K100682
• Device Name: GSP NEONATAL 17A-OH-PROGESTERONE KIT MODEL: 3305-001U
• Applicant: Wallac OY
• Product Code: JLX · Clinical Chemistry
• Decision Date: Jul 23, 2010
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 862.1395
• Device Class: Class 1
• Attributes: Pediatric

Indications for Use

The GSP Neonatal 17α-OH-progesterone kit is intended for the quantitative determination of human 17α-OHprogesterone in blood specimens dried on filter paper as an aid in screening newborns for congenital adrenal hyperplasia (CAH) using the GSP™ instrument.

Device Story

The GSP Neonatal 17α-OH-progesterone kit is an in vitro diagnostic assay for newborn screening. It utilizes dried blood spot samples collected on filter paper. The device employs a solid-phase, time-resolved fluoroimmunoassay principle: competitive binding between europium-labeled 17-OHP and sample 17-OHP for rabbit polyclonal antibody sites. Danazol is used to release 17-OHP from binding proteins. A secondary anti-rabbit IgG antibody coated on the microtitration plate facilitates separation. DELFIA Inducer dissociates europium ions to form fluorescent chelates, which are measured by the GSP instrument. Fluorescence is inversely proportional to 17-OHP concentration. The assay is performed by trained laboratory personnel in clinical settings. Results assist clinicians in identifying newborns at risk for CAH, facilitating early diagnosis and management.

Clinical Evidence

Method comparison study using 2,589 routine/retrospective newborn screening specimens. Regression analysis (n=2567) showed Y = 0.97x + 0.27 (r=0.96). Screening performance evaluated against predicate across three birth weight categories (<1250g, 1250-2249g, ≥2250g) using 90th, 95th, and 99th percentile cut-offs. Positive percent agreement ranged from 33.3% to 100% depending on weight category and cut-off; negative percent agreement ranged from 97.6% to 100%.

Technological Characteristics

Solid-phase, time-resolved fluoroimmunoassay. Materials: Rabbit polyclonal antibodies, goat anti-rabbit IgG coated microtitration strips, Whatman no. 903 filter paper. Energy source: GSP instrument (optical measurement). Connectivity: GSP instrument-based. Software: Automated immunoassay processing. Sterilization: Not applicable (reagent kit).

Indications for Use

Indicated for the quantitative determination of 17α-OH-progesterone in dried blood spot specimens to aid in screening newborns for congenital adrenal hyperplasia (CAH).

Regulatory Classification

Identification

A 17-hydroxyprogesterone test system is a device intended to measure 17-hydroxyprogesterone (a steroid) in plasma and serum. Measurements of 17-hydroxyprogesterone are used in the diagnosis and treatment of various disorders of the adrenal glands or the ovaries.

Predicate Devices

• AutoDELFIA® Neonatal 17a-OH-progesterone kit (K081922)

Submission Summary (Full Text)

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# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY ASSAY ONLY TEMPLATE

A. 510(k) Number:
k100682

B. Purpose for Submission:
New device

C. Measurand:
17-α-hydroxyprogesterone (17-OHP)

D. Type of Test:
Quantitative, time-resolved fluoroimmunoassay

E. Applicant:
Wallac Oy, a Subsidiary of PerkinElmer, Inc.

F. Proprietary and Established Names:
GSP Neonatal 17α-OH-progesterone kit

G. Regulatory Information:
1. Regulation section:
21 CFR § 862.1395 17-Hydroxyprogesterone test system
2. Classification:
Class I, meets limitations of exemptions per 21 CFR § 862.9 (c)(2)
3. Product code:
JLX, Radioimmunoassay, 17-Hydroxyprogesterone
4. Panel:
Clinical Chemistry (75)

H. Intended Use:
1. Intended use(s):
The GSP Neonatal 17α-OH-progesterone kit is intended for the quantitative determination of human 17α-OH-progesterone in blood specimens dried on filter paper as an aid in screening newborns for congenital adrenal hyperplasia (CAH) using the GSP™ instrument.
2. Indication(s) for use:
See intended use above
3. Special conditions for use statement(s):
- For prescription use only
- For in vitro diagnostic use only

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- As with any other in vitro screening assays, the data obtained using the GSP Neonatal 17α-OH-progesterone kit should be used as an aid to other medically established procedures and results interpreted in conjunction with other clinical data available to the clinician.

4. Special instrument requirements:
Only for use on the GSP Instrument

I. Device Description:
The GSP Neonatal 17α-OH-progesterone kit consists of the following components (to perform 1152 assays):

Six calibrators (at approximately 0, 4, 10, 25, 75 and 220 ng/mL serum) and three controls (at approximately 17, 45 and 100 mg/mL serum) prepared from washed human blood, with preservative, adjusted to a hematocrit of 50-55%, calibrated using gravimetric methods and spotted onto Whatman 903 specimen collection paper.

17-OHP europium tracer (ready-for-use) in Tris-HCl buffered (pH 7.8) salt solution with bovine serum albumin and preservative.

17-OHP rabbit polyclonal antiserum in Tris-HCl buffered (pH 7.8) salt solution with bovine serum albumin and preservative.

17-OHP assay buffer (ready-for-use), a Tris-HCl buffered (pH 7.8) salt solution with bovine serum albumin, Tween 40, polyethylene glycol 6000, CaCl₂, danazol, an inert red dye and preservative.

Anti-rabbit IgG microtitration strips coated with goat anti-rabbit antibody.

All human source materials used in the preparation of kit components was tested and found to be negative for hepatitis B surface antigen, anti-hepatitis C and anti-HIV 1 and 2 antibodies by FDA approved methods.

J. Substantial Equivalence Information:

1. Predicate device name(s):
AutoDELFIA Neonatal 17α-OH-progesterone kit

2. Predicate K number(s):
k081922

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3. Comparison with predicate:

| Item | Device | Predicate |
| --- | --- | --- |
| Similarities | | |
| Intended use/Indications for use | The 17α-OH-progesterone kit is intended for the quantitative determination of human 17-OHP in blood specimens dried on filter paper as an aid in screening newborns for CAH. | same |
| Chemical principle | Competitive reaction between europium labeled 17-OHP and sample 17-OHP for a limited number of binding sites on 17-OHP specific polyclonal antibodies derived from rabbit | same |
| Detection principle | Time-resolved fluorescence | same |
| Specimen | Neonatal dried blood spot punch with a diameter of approximately 3.2 mm (1/8 inch) | same |
| Antibodies | Rabbit polyclonal antibodies | same |
| Calibrator and control matrix | Human blood with a hematocrit of 50-55% and spotted onto filter paper cassettes (Whatman Grade 903) | same |
| Controls | 3 levels (approx. values 17, 45 and 100 ng/mL serum) | same |
| Calibrators | 6 levels (approx. values 0, 4, 10, 25, 75 and 220 ng/mL serum) | same |
| Assay buffer | 17-OHP assay buffer, ready for use | same |
| Coated plates | Anti-rabbit IgG microtitration strips, 8 x 12 wells coated with anti-rabbit IgG (raised in goat) | same |
| Measuring range | 1.4 to 220 ng/mL serum | same |
| Item | Device | Predicate |
| --- | --- | --- |
| Differences | | |
| Instrument | GSP Instrument | 1235 AutoDELFIA Instrument |
| Dissociation solution | DELFIA Inducer | Enhancement Solution |
| Antibody cross-reactions in the assay | 21-Deoxycortisol 0.84 %17αOH pregnenolone sulfate 0.77%11-Deoxycortisol 0.49 %17α-OH pregnenolone 0.80 %Progesterone 0.20 % | 21-Deoxycortisol 0.91 %17αOH pregnenolone sulfate 0.78%11-Deoxycortisol 0.62 %17α-OH pregnenolone 0.83 %Progesterone 0.37 %Deoxycorticosterone 0.02 % |

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| | Deoxycorticosterone 0.01 % | |
| --- | --- | --- |
| Analytical specificity | Triglycerides (Intralipid) 3000 mg/dL (at 30 and 80 ng/mL serum 17-OHP) and 750 mg/dL (at 150 ng/mL serum 17-OHP) | Triglycerides (Intralipid) 3000 mg/dL (at 25 and 70 mg/dL serum 17-OHP) |
| Tracer | 17-OHP- europium tracer stock solution, approximate concentration of 6 nmol/L, ready-to-use | 17-OHP- europium tracer stock solution, approximate concentration of 40 nmol/L, lyophilized |
| Detection limits | Limit of Blank, 0.42 ng/mL serum
Limit of Detection, 1.4 ng/mL serum | Limit of Blank, 0.37 ng/mL serum
Limit of Detection, 0.84 ng/mL serum |
| Precision (total variation using a full calibration curve on each plate) | 3.20 ng/mL serum CV% 14.9
5.30 ng/mL serum CV% 13.9
16.9 ng/mL serum CV% 11.3
51.6 ng/mL serum CV% 9.4
92.5 ng/mL serum CV% 10.9
131 ng/mL serum CV% 10.1
161 ng/mL serum CV% 10.9
187 ng/mL serum CV% 12.0 | 2.12 ng/mL serum CV% 13.0
4.69 ng/mL serum CV% 9.8
7.52 ng/mL serum CV% 14.8
27.0 ng/mL serum CV% 8.3
54.4 ng/mL serum CV% 9.2
109 ng/mL serum CV% 10.8
182 ng/mL serum CV% 9.1 |
| Expected values in newborns (per birth weight and 95th percentile) | < 1250 g 94.1 ng/mL serum
1250-2249 g 47.5 ng/mL serum
≥ 2250 g 13.8 ng/mL serum | Site 1:
< 1250 g 73.6 ng/mL serum
1250-2249 g 40.8 ng/mL serum
≥ 2250 g 20.9 ng/mL serum
Site 2:
< 1250 g 95.0 ng/mL serum
1250-2249 g 68.6 ng/mL serum
≥ 2250 g 28.3 ng/mL serum |

## K. Standard/Guidance Document Referenced (if applicable):

- Evaluation of Precision Performance of Quantitative Measurement Methods; Approved Guideline – Second Edition (CLSI EP5-A2)
- Evaluation of the Linearity of Quantitative Measurement Procedures: A Statistical Approach; Approved Guideline (CLSI EP6-A)
- Interference Testing in Clinical Chemistry; Approved Guideline (CLSI EP7-A)
- Method Comparison and Bias Estimation Using Patient Samples; Approved Guideline – Second Edition (CLSI EP9-A2)
- Protocols for Determination of Limits of Detection and Limits of Quantitation; Approved Guideline (CLSI EP17-A)
- Stability Testing of In Vitro Diagnostic Reagents; 2002 (CEN 13640)

## L. Test Principle:

The GSP Neonatal 17α-OH-progesterone assay is a solid phase, time-resolved fluoroimmunoassay based on the competitive reaction between europium-labeled 17-OHP and sample 17-OHP for a limited amount of binding sites on 17-OHP specific polyclonal antibodies (derived from rabbit). Danazol facilitates the release of 17-OHP

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from the binding proteins. A second antibody, directed against rabbit IgG, is coated to the solid phase, giving convenient separation of the antibody-bound and free antigen.

DELFIA Inducer dissociates europium ions from the labeled antigen into solution where they form highly fluorescent chelates with components of the DELFIA Inducer. The fluorescence in each well is then measured. The fluorescence of each sample is inversely proportional to the concentration of 17-OHP in the sample.

# M. Performance Characteristics (if/when applicable):

# 1. Analytical performance:

# a. Precision/Reproducibility:

The precision of the GSP Neonatal 17-OHP Kit was evaluated following the recommendations in the CLSI EP5-A2 guideline. Eight whole blood specimens were obtained from adults, the hematocrit was adjusted to $50 - 55\%$ and spiked with 17-OHP at concentrations across the reportable range of the test. The samples were then dispensed onto filter paper and dried at room temperature overnight. The samples were tested over 28 days using three kit lots and three GSP analyzers, for a total of 216 measurements per sample. The sponsor also calculated the within run SD and within run CV % for each sample measured using the same lot and the same instrument. Each sample was measured 24 times (on 3 different runs) using the same lot/instrument combination. The sponsor reported the "range" which is the minimum and maximum within run SDs observed for samples $\leq 4\mathrm{ng / mL}$ serum and the minimum and maximum within run CVs % observed for samples $&gt;4\mathrm{ng / mL}$ serum. The results are summarized below:

Precision data using a full calibration curve on each plate:

| Mean 17-OHP (ng/mL serum) | Within run variation | | Within lot variation | | Total variation | |
| --- | --- | --- | --- | --- | --- | --- |
| | SD Mean/Range | CV% Mean/Range | SD | CV% | SD | CV% |
| 3.2 | 0.4 (0.29 to 0.47) | 13.1 | 0.4 | 13.6 | 0.5 | 14.9 |
| 5.3 | 0.5 | 9.7 (6.1 to 12.5) | 0.7 | 13.5 | 0.7 | 13.9 |
| 16.9 | 1.4 | 8.2 (5.7 to 9.9) | 1.9 | 11.0 | 1.9 | 11.3 |
| 51.6 | 4.0 | 7.7 (5.4 to 9.9) | 4.6 | 8.8 | 4.8 | 9.4 |
| 92.5 | 7.5 | 8.2 (5.2 to 11.0) | 9.0 | 9.8 | 10.1 | 10.9 |
| 131 | 9.6 | 7.3 (5.4 to 8.9) | 11.5 | 8.8 | 13.2 | 10.1 |
| 161 | 13.2 | 8.2 (6.2 to 9.9) | 15.1 | 9.4 | 17.5 | 10.9 |
| 187 | 18.6 | 10.0 (6.7 to 13.3) | 20.5 | 10.9 | 22.4 | 12.0 |

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Precision data using one calibration curve valid for 24 hours:

| Mean 17-OHP (ng/mL serum) | Within run variation | | Within lot variation | | Total variation | |
| --- | --- | --- | --- | --- | --- | --- |
| | SD Mean/Range | CV% Mean/Range | SD | CV% | SD | CV% |
| 3.2 | 0.4 (0.31 to 0.49) | 13.2 | 0.4 | 13.6 | 0.5 | 14.9 |
| 5.3 | 0.6 | 10.5 (6.4 to 13.5) | 0.7 | 13.2 | 0.7 | 13.6 |
| 17.0 | 1.6 | 9.5 (6.7 to 12.9) | 2.0 | 11.6 | 2.0 | 11.9 |
| 52.0 | 3.9 | 7.5 (5.5 to 9.4) | 4.6 | 8.8 | 4.9 | 9.5 |
| 93.0 | 7.8 | 8.4 (5.2 to 11.1) | 9.2 | 9.9 | 10.7 | 11.5 |
| 132 | 9.9 | 7.5 (5.4 to 9.6) | 12.2 | 9.3 | 14.6 | 11.1 |
| 163 | 14.9 | 9.1 (7.8 to 11.4) | 16.0 | 9.8 | 19.3 | 11.8 |
| 189 | 20.4 | 10.8 (8.4 to 15.1) | 22.7 | 12.0 | 25.4 | 13.4 |

In addition, the kit control materials were assayed to determine the precision of the kit. Three lots of control materials were tested over 28 days using three reagent kit lots and three analyzers, for a total of 72 measurements per control sample for each lot and 216 pooled measurements per control sample. The pooled results from the three lots of control materials are summarized below:

Precision data using a full calibration curve on each plate:

| Sample | Mean 17-OHP (ng/mL serum) | Within run Variation | | Within lot Variation | | Total Variation | |
| --- | --- | --- | --- | --- | --- | --- | --- |
| | | SD | CV% | SD | CV% | SD | CV% |
| C1 | 14.3 | 0.7 | 4.8 | 0.8 | 5.8 | 0.93 | 6.5 |
| C2 | 43.6 | 2.3 | 5.2 | 2.9 | 6.7 | 3.78 | 8.7 |
| C3 | 90.7 | 5.7 | 6.2 | 7.3 | 8.0 | 8.20 | 9.0 |

Precision data using one calibration curve valid for 24 hours:

| Sample | Mean 17-OHP (ng/mL serum) | Within run Variation | | Within lot Variation | | Total Variation | |
| --- | --- | --- | --- | --- | --- | --- | --- |
| | | SD | CV% | SD | CV% | SD | CV% |
| C1 | 14.4 | 0.8 | 5.3 | 0.9 | 6.3 | 0.98 | 6.8 |
| C2 | 43.9 | 2.4 | 5.5 | 3.0 | 6.7 | 3.91 | 8.9 |
| C3 | 91.1 | 5.7 | 6.3 | 7.3 | 8.0 | 8.35 | 9.2 |

b. Linearity/assay reportable range:

The study was determined in accordance with CLSI EP6-A. Whole blood specimens were obtained from six apparently healthy adults and the hematocrit was adjusted to $50 - 55\%$. The three specimens that had low endogenous 17-OHP were pooled. A part of the pooled specimen was spiked

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to create a sample with high 17-OHP concentration (approximately 250 ng/mL serum). The high and low pools were mixed in varying proportions to create a dilution series of varying 17-OHP concentrations ranging from 0.9 to 213 ng/mL serum for kit lot 1 and 0.84 to 245 ng/mL serum for kit lot 2. The samples were spotted on filter paper and dried overnight. The 17-OHP concentrations of the series of dried blood spot samples were measured in replicates of four with two kit lots and two instruments in random order.

The data was analyzed using linear regression as well as second and third order non-linear fitted polynomial regression. The third order model fit the data better than the linear model. However, for dilution points greater than 4 ng/mL, the maximum observed difference (%) between the models was 8.7 % (kit lot 1) and 9.3 % (kit lot 2). For concentrations ≤ 4 ng/mL, the observed absolute difference between the models was 0.18 ng/mL (kit lot 1) and 0.22 ng/mL (kit lot 2). The observed difference between the models was within the sponsor's pre-determined acceptance criteria for linearity.

The sponsor concluded that the assay is linear from 1.4 to 229 ng/mL serum. The reportable range of the assay is 1.4 to 220 ng/mL.

c. Traceability, Stability, Expected values (controls, calibrators, or methods): There is no international reference preparation or reference method for 17-OHP. The GSP Neonatal 17-OHP kits are traceable to commercially available purified 17-OHP.

Six calibrator and three control materials are supplied with the kit as dried blood spots on Whatman 903 filter paper. They are prepared from human blood with a hematocrit value of 50 to 55 % and purified 17-OHP and calibrated using gravimetric methods. The values for the calibrators and controls are assigned using multiple replicates on GSP instruments and provided on lot specific quality control certificates. The calibrator and control materials to be used with this assay have been previously cleared under k081922.

Real-time stability including shelf-life, transport, and in-use stability studies for the entire kit were performed, including the controls and calibrators. The sponsor has demonstrated a shelf life for all reagents of 12 months when stored at 2 to 8 °C. Once opened, calibrators, controls and plates are stable for 14 days when stored at 2 to 8 °C. The on-board stability of the tracer, antiserum and assay buffer is 5 days.

d. Detection limit:

The limit of blank (LoB) and limit of detection (LoD) studies were performed following the recommendations in CLSI EP17-A. The LoB was calculated from data using two kit lots and two instruments over 4 testing days and a total of 120 measurements of blank (analyte free) dried blood spot samples on

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filter paper. Statistical analysis yielded a LoB of 0.42 ng/mL serum.

To estimate the LoD, five low level samples (dried blood spot samples on filter paper) were prepared from heparinized whole blood. Repeated measurements of each sample (n = 216) were carried out using the proposed device. Statistical analysis yielded a LoD of 1.4 ng/mL serum.

The package insert states that values below 1.4 ng/mL serum should be reported as “&lt;1.4 ng/mL serum.”

e. Analytical specificity:

Interference from various compounds was evaluated at 17-OHP concentrations of approximately 30, 80 and 150 ng/mL serum. The potential interferent was added to whole blood specimens containing 17-OHP, spotted onto filter paper, dried, and tested. Specimens without added interferent (solvent alone) were also tested (control). The sponsor concluded that a potential interferent did not interfere with the assay when the observed effect with 95% confidence was &lt; 15% in the clinically relevant range (i.e. 10 to 150 ng/mL serum 17-OHP).

| Compound | Concentration added to samples |
| --- | --- |
| Bilirubin (conjugated) | 20 mg/dL |
| Bilirubin (unconjugated) | 20 mg/dL |
| Hemoglobin | 0.5 g/dL |
| Triglycerides (Intralipid) | 3000 mg/dL (30 and 80 ng/mL serum 17-OHP) and 750 mg/dL (150 ng/mL serum 17-OHP) |

The sponsor concluded that none of the compounds at the tested levels interfered with the assay.

Compounds whose structures are similar to 17-OHP were evaluated for potential cross-reactivity using a published method. The lists of compounds tested and results are summarized below:

| Substance | Cross reactivity % |
| --- | --- |
| 21-Deoxycortisol | 0.84 |
| 17α-OH pregnenolone | 0.80 |
| 17α-OH pregnenolone sulfate | 0.77 |
| 11-Deoxycortisol | 0.49 |
| Progesterone | 0.20 |
| Deoxycorticosterone | 0.01 |
| Cortisol | <0.01 |
| 5β-Dihydrocortisol | <0.01 |
| Cortisone | <0.01 |
| 5β-Dihydrocortisone | <0.01 |
| Dehydroisoandrosterone | <0.01 |
| Dehydroisoandrosterone sulfate | <0.01 |

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| Dexamethasone | <0.01 |
| --- | --- |
| 17β-Estradiol | <0.01 |
| Estriol | <0.01 |
| Prednisone | <0.01 |
| Prednisolone | <0.01 |
| Pregnenolone | <0.01 |
| 16α-OH pregnenolone | <0.01 |
| 17α-OH pregnenolone glucuronide | <0.01 |
| 16α-OH progesterone | <0.01 |
| 20α-Dihydroprogesterone | <0.01 |
| Spironolactone | <0.01 |
| Testosterone | <0.01 |

f. Assay cut-off:

See "clinical cut-off" and "expected values/reference range" sections below for discussion on the assay cut-off.

2. Comparison studies:

a. Method comparison with predicate device:

The study was performed in a routine newborn screening laboratory following the recommendations in CLSI EP9-A2. The concentration of 17-OHP was measured in a total of 2589 infants representing the US population. The specimens were routine and retrospective screening specimens. The results were analyzed and classified according to the birth weights of the infants and are summarized in the tables below:

Descriptive statistics, proposed device

| Birth weight (g) | n | 17-OHP (ng/mL serum) | | Percentile (ng/mL serum) | | |
| --- | --- | --- | --- | --- | --- | --- |
| | | Mean | Median | 90th | 95th | 99th |
| ≥2250 | 1820 | 6.9 | 6.0 | 11.3 | 13.8 | 23.4 |
| 1250–2249 | 438 | 17.5 | 11.0 | 40.0 | 47.5 | 70.7 |
| <1250 | 308 | 38.6 | 31.0 | 78.9 | 94.1 | 150.2 |

A regression analysis was performed to compare the proposed device to the predicate. The specimens $(n = 2567)$ within the measuring range of the proposed device (1.4 to $220\mathrm{ng / mL}$ serum) were analyzed. A weighted regression analysis was performed and the regression analysis results are summarized below:

| Regression equation | 95 % CI for regression coefficients | Residual standard error | Correlation coefficient (r) |
| --- | --- | --- | --- |
| Y = 0.97 x + 0.27 | Slope: (0.96; 0.98) | 0.16 | 0.96 |
| | Intercept: (0.21; 0.32) | | |

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Screening Performance (Screening results and true diagnosis of the proposed device):

Using the data from non-CAH samples, the cut-offs were determined by calculating the 17-OHP concentrations corresponding to the $90^{\text{th}}$ , $95^{\text{th}}$ and $99^{\text{th}}$ population percentiles. The results for the screening performance of the proposed device including 23 confirmed retrospective CAH diagnosed specimens are summarized in the tables below:

&lt; 1250 g weight category, $90^{\text{th}}$ percentile-based cut-off.

| Proposed Cut-off 78.9 ng/mL | Predicate Cut-off 71.8 ng/mL | Total Subjects | Diagnosed CAH | No diagnosed CAH |
| --- | --- | --- | --- | --- |
| + | + | 25 | 0 | 25 |
| + | - | 6 | 0 | 6 |
| - | + | 6 | 0 | 6 |
| - | - | 271 | 0 | 271 |
| Total | | 308 | 0 | 308 |

Overall percent agreement $= ((25 + 71) / 308)) * 100\% = 96.1\%$
Positive percent agreement $= (25 / 31)*100\% = 80.6\%$
Negative percent agreement $= (271 / 277)*100\% = 97.8\%$

&lt; 1250 g weight category, $95^{\text{th}}$ percentile-based cut-off.

| Proposed Cut-off 94.1 ng/mL | Predicate Cut-off 86.6 ng/mL | Total Subjects | Diagnosed CAH | No diagnosed CAH |
| --- | --- | --- | --- | --- |
| + | + | 11 | 0 | 11 |
| + | - | 5 | 0 | 5 |
| - | + | 5 | 0 | 5 |
| - | - | 287 | 0 | 287 |
| Total | | 308 | 0 | 308 |

Overall percent agreement $= (11 + 287) / 308)*100\% = 96.8\%$
Positive percent agreement $= (11 / 16)*100\% = 68.8\%$
Negative percent agreement $= (287 / 292)*100\% = 98.3\%$

&lt; 1250 g weight category, $99^{\text{th}}$ percentile-based cut-off.

| Proposed Cut-off 150.2 ng/mL | Predicate Cut-off 143.9 ng/mL | Total Subjects | Diagnosed CAH | No diagnosed CAH |
| --- | --- | --- | --- | --- |
| + | + | 4 | 0 | 4 |
| + | - | 0 | 0 | 0 |
| - | + | 0 | 0 | 0 |
| - | - | 304 | 0 | 304 |
| Total | | 308 | 0 | 308 |

Overall percent agreement $= (4 + 304) / 308)*100\% = 100\%$
Positive percent agreement $= (4 / 4)*100\% = 100\%$
Negative percent agreement $= (304 / 304)*100\% = 100\%$

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1250-2249g weight category, 90th percentile-based cut-off

| Proposed Cut-off 40.0 ng/mL | Predicate Cut-off 35.4 ng/mL | Total Subjects | Diagnosed CAH | No diagnosed CAH |
| --- | --- | --- | --- | --- |
| + | + | 42 | 1 | 41 |
| + | - | 3 | 0 | 3 |
| - | + | 3 | 0 | 3 |
| - | - | 391 | 0 | 391 |
| Total | | 439 | 1 | 438 |

Overall percent agreement = (42+391)/439)*100% = 98.6 %
Positive percent agreement = (42/45)*100% = 93.3 %
Negative percent agreement = (391/394)*100% = 99.2 %

1250 - 2249g weight category, 95th percentile-based cut-off

| Proposed Cut-off 47.5 ng/mL | Predicate Cut-off 43.8 ng/mL | Total Subjects | Diagnosed CAH | No diagnosed CAH |
| --- | --- | --- | --- | --- |
| + | + | 20 | 1 | 19 |
| + | - | 3 | 0 | 3 |
| - | + | 3 | 0 | 3 |
| - | - | 413 | 0 | 413 |
| Total | | 439 | 1 | 438 |

Overall percent agreement = (20+413)/439)*100% = 98.6 %
Positive percent agreement = (20/23)*100% = 87.0 %
Negative percent agreement = (413/416)*100% = 99.3 %

1250 - 2249g weight category, 99th percentile-based cut-off

| Proposed Cut-off 70.7 ng/mL | Predicate Cut-off 62.6 ng/mL | Total Subjects | Diagnosed CAH | No diagnosed CAH |
| --- | --- | --- | --- | --- |
| + | + | 2 | 1 | 1 |
| + | - | 4 | 0 | 4 |
| - | + | 4 | 0 | 4 |
| - | - | 429 | 0 | 429 |
| Total | | 439 | 1 | 438 |

Overall percent agreement = (2+429)/439)*100% = 98.2 %
Positive percent agreement = (2/6)*100% = 33.3 %
Negative percent agreement = (429/433)*100% = 99.1 %

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$\geq 2250 \mathrm{~g}$ weight category, $90^{\text{th}}$ percentile-based cut-off

| Proposed Cut-off 11.3 ng/mL | Predicate Cut-off 12.1 ng/mL | Total Subjects | Diagnosed CAH | No diagnosed CAH |
| --- | --- | --- | --- | --- |
| + | + | 165 | 22 | 143 |
| + | - | 39 | 0 | 39 |
| - | + | 36 | 0 | 36 |
| - | - | 1602 | 0 | 1602 |
| Total | | 1842 | 22 | 1820 |

Overall percent agreement $= (165 + 1602) / 1842) * 100\% = 95.9\%$

Positive percent agreement $= (165 / 201)^{*}100\% = 82.1\%$

Negative percent agreement $= (1602 / 1641)^{*}100\% = 97.6\%$

$\geq 2250 \mathrm{~g}$ weight category, $95^{\text{th}}$ percentile-based cut-off

| Proposed Cut-off 13.8 ng/mL | Predicate Cut-off 14.7 ng/mL | Total subjects | Diagnosed CAH | No diagnosed CAH |
| --- | --- | --- | --- | --- |
| + | + | 95 | 22 | 73 |
| + | - | 16 | 0 | 16 |
| - | + | 18 | 0 | 18 |
| - | - | 1713 | 0 | 1713 |
| Total | | 1842 | 22 | 1820 |

Overall percent agreement $= (95 + 1713) / 1842)^{*}100\% = 98.2\%$

Positive percent agreement $= (95 / 113)^{*}100\% = 84.1\%$

Negative percent agreement $= (1713 / 1729)^{*}100\% = 99.1\%$

$\geq 2250 \mathrm{~g}$ weight category, $99^{\text{th}}$ percentile-based cut-off

| Proposed Cut-off 23.4 ng/mL | Predicate Cut-off 22.1 ng/mL | Total subjects | Diagnosed CAH | No diagnosed CAH |
| --- | --- | --- | --- | --- |
| + | + | 39 | 22 | 17 |
| + | - | 2 | 0 | 2 |
| - | + | 1 | 0 | 1 |
| - | - | 1800 | 0 | 1800 |
| Total | | 1842 | 22 | 1820 |

Overall percent agreement $= (39 + 1800) / 1842)^{*}100\% = 99.8\%$

Positive percent agreement $= (39 / 40)^{*}100\% = 97.5\%$

Negative percent agreement $= (1800 / 1802)^{*}100\% = 99.9\%$

b. Matrix comparison:

Not applicable. The device should only be used with neonatal whole blood from heel prick dried on filter paper.

3. Clinical studies:

a. Clinical Sensitivity:

Not applicable.

b. Clinical specificity:

Not applicable.

{12}

c. Other clinical supportive data (when a. and b. are not applicable): Not applicable.

4. Clinical cut-off:

The package insert states “the concentration of 17-OHP in newborns depends on demographic variations, age, weight, prematurity and twinning. Birth weight or gestational age, or both, are the most common categories in screening programs. The laboratory needs to establish its own cut-off values, which can be based on a percentile, or on the basis of a normal range. Cut-off levels related to e.g. gestational age, infant age and birth weight need to be validated for each screening population.”

The product insert recommends the follow-up algorithm for CAH screening described by the American College of Medical Genetics at: http://www.acmg.net/resources/policies/ACT/Visio-NBS_Elevated-17OHP_4-18-06.pdf

5. Expected values/Reference range:

The distribution of 17-OHP concentration of a normal newborn population (USA) was established using the proposed device by measuring the concentration of 17-OHP in a total of 2566 infants representing the US population. The specimens were routine and retrospective screening specimens. The following descriptive statistics and percentile cut-offs are included in the package insert:

| Birth weight (g) | N | 17-OHP (ng/mL serum) | | Percentile (ng/mL serum) | | |
| --- | --- | --- | --- | --- | --- | --- |
| | | Mean | Median | 90^{th} | 95^{th} | 99^{th} |
| ≥2250 | 1820 | 6.9 | 6.0 | 11.3 | 13.8 | 23.4 |
| 1250–2249 | 438 | 17.5 | 11.0 | 40.0 | 47.5 | 70.7 |
| <1250 | 308 | 38.6 | 31.0 | 78.9 | 94.1 | 150.2 |

The package insert includes precautionary language that each laboratory should establish its own reference range and cut-off values and that cut-offs from another 17-OHP screening test should not be used.

N. Proposed Labeling:

The labeling is sufficient and it satisfies the requirements of 21 CFR Part 809.10.

O. Conclusion:

The submitted information in this premarket notification is complete and supports a substantial equivalence decision.