ImmunoCAP Tryptase is an in vitro semi-quantitative assay for measurement of tryptase in human serum or plasma (EDTA, lithium heparin or sodium heparin). It is intended for in vitro diagnostic use as an aid in the clinical diagnosis of patients with a suspicion of systemic mastocytosis in conjunction with other clinical and laboratory findings. ImmunoCAP Tryptase is to be used with the instruments Phadia 100, and Phadia 250.
Device Story
ImmunoCAP Tryptase is an in vitro diagnostic assay for measuring tryptase levels in human serum or plasma. The device utilizes anti-tryptase antibodies covalently coupled to an ImmunoCAP solid phase; patient samples are incubated with the solid phase, followed by the addition of enzyme-labeled anti-tryptase antibodies. After washing steps to remove unbound components, a developing agent is added; the resulting fluorescence is measured to quantify tryptase concentration. The assay is performed on Phadia 100 and Phadia 250 instruments, which automate processing and result calculation. Used in clinical laboratory settings by trained personnel, the output provides a semi-quantitative concentration value. This result assists clinicians in diagnosing systemic mastocytosis by providing objective biochemical data to support clinical evaluation.
Clinical Evidence
Clinical performance verified at two sites with 138 patients suspected of systemic mastocytosis. Study compared updated ImmunoCAP Tryptase against the currently cleared version. Results confirmed clinical performance remains unchanged for aiding diagnosis according to WHO criteria. Analytical performance verified via precision, lot-to-lot reproducibility, linearity, limit of detection, hook effect, analytical specificity, HAMA interference, recovery, and sample matrix studies.
Technological Characteristics
In vitro semi-quantitative immunoassay. Principle: Fluorescence enzyme immunoassay (FEIA). Components: Anti-tryptase coupled to ImmunoCAP, enzyme-labeled anti-tryptase antibodies. Instrumentation: Phadia 100 and Phadia 250. Sample types: Serum, EDTA plasma, lithium heparin plasma, sodium heparin plasma. Automated processing and calculation.
Indications for Use
Indicated for patients with suspected systemic mastocytosis, including adults and pediatric populations, to aid in clinical diagnosis via measurement of serum or plasma tryptase levels.
Regulatory Classification
Identification
A tryptase test system is a device that aids in the diagnosis of systemic mastocytosis. It is intended for in vitro diagnostic use as an aid in the clinical diagnosis of patients with a suspicion of systemic mastocytosis in conjunction with other clinical and laboratory findings.
Special Controls
*Classification.* Class II (special controls). The special control is FDA's guideline entitled “Class II Special Controls Guideline: Tryptase Test System as an Aid in the Diagnosis of Systemic Mastocytosis.” For availability of the document, see § 866.1(e).
{0}
1
# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY
A. 510(k) Number:
K173704
B. Purpose for Submission:
Modification to an existing device
C. Measurand:
Tryptase
D. Type of Test:
Fluorescence immunoassay
E. Applicant:
Phadia US Inc.
F. Proprietary and Established Names:
ImmunoCAP Tryptase
ImmunoCAP Tryptase Calibrators
ImmunoCAP Tryptase Conjugate 50
ImmunoCAP Tryptase Calibrator Strip, ImmunoCAP Tryptase Control Strip
G. Regulatory Information:
1. Regulation section:
21 CFR §866.5760, Tryptase test system
2. Classification:
Class II
{1}
3. Product code:
OYL; Tryptase Assay System
4. Panel:
Immunology (82)
H. Intended Use:
1. Intended use:
ImmunoCAP Tryptase is an in vitro semi-quantitative assay for measurement of tryptase in human serum or plasma (EDTA, lithium heparin or sodium heparin). It is intended for in vitro diagnostic use as an aid in the clinical diagnosis of patients with a suspicion of systemic mastocytosis in conjunction with other clinical and laboratory findings. ImmunoCAP Tryptase is to be used with the instruments Phadia 100, and Phadia 250.
2. Indication for use:
Same as intended use.
3. Special conditions for use statement:
Prescription use only.
4. Special instrument requirements:
For use with the Phadia 100 and Phadia 200 instruments
I. Device Description:
ImmunoCAP Tryptase is a fluorescence immunoassay for the measurement of total tryptase in human serum or plasma, based on the ImmunoCAP solid phase. ImmunoCAP Tryptase concentrations are semi-quantitatively reported in microgram/L (μg/L). ImmunoCAP Tryptase reagents are modular in concept and are available individually in different package sizes dependent on instrument system used.
J. Substantial Equivalence Information:
1. Predicate device name:
ImmunoCAP Tryptase
{2}
2. Predicate 510(k) number:
K103039
3. Comparison with predicate:
| Similarities | | |
| --- | --- | --- |
| Item | Device | Predicate |
| Intended Use | ImmunoCAP Tryptase is an in vitro semi-quantitative assay for measurement of tryptase in human serum or plasma (EDTA, lithium heparin or sodium heparin). It is intended for in vitro diagnostic use as an aid in the clinical diagnosis of patients with a suspicion of systemic mastocytosis in conjunction with other clinical and laboratory findings. ImmunoCAP Tryptase is to be used with the instruments Phadia 100 and Phadia 250 | ImmunoCAP Tryptase is an in vitro semi-quantitative assay for measurement of tryptase in human serum or plasma (EDTA, lithium heparin or sodium heparin). It is intended for in vitro diagnostic use as an aid in the clinical diagnosis of patients with a suspicion of systemic mastocytosis in conjunction with other clinical and laboratory findings. ImmunoCAP Tryptase is to be used with the instruments Phadia 100, Phadia 250 and Phadia 1000. |
| Sample matrix | Human serum or plasma (EDTA, lithium heparin or sodium heparin) | Same |
| Tryptase Conjugate | Anti-tryptase mouse monoclonal antibodies coupled to β-Galactosidase | Same |
| Analytical Technology | Immunofluorescence measurement | Same |
| Reporting of Results | Semi-quantitative, μg/L | Same |
| Analytical sensitivity (LoD) | < 1 μg/L | Same |
| Software | Same ImmunoCAP Tryptase method on IDM and Prime (data management software) | Same |
{3}
| Differences | | |
| --- | --- | --- |
| Item | Device | Predicate |
| Assay system (Tryptase Anti-Tryptase, Tryptase Control, Tryptase Sample Diluent, Instruments) | ImmunoCAP Tryptase run on Phadia 100 and Phadia 250. | ImmunoCAP Tryptase run on Phadia 100, Phadia 250 and Phadia 1000. |
| Tryptase Conjugate raw material | Fragmented F(ab')2 antibody | Intact antibody |
| | Concentration β-Galactosidase-anti-tryptase: approximately 1.6 μg/ml | Concentration β-Galactosidase-anti-tryptase: approximately 3.5 μg/ml |
| Tryptase Calibrators/Curve control raw material | Human recombinant tryptase | Human lung tryptase |
K. Standard/Guidance Document Referenced (if applicable):
CLSI EP25-A: Evaluation of Stability of In Vitro Diagnostic reagents; Approved Guideline.
CLSI EP05-A3: Evaluation of Precision of Quantitative Measurement Procedures; Approved Guideline-Third Edition.
CLSI EP17-A2: Evaluation of Detection Capability for Clinical Laboratory Measurement Procedures; Approved Guideline-Second Edition.
CLSI EP07-A2: Interference Testing in Clinical Chemistry; Approved Guideline Second Edition.
L. Test Principle:
Anti-tryptase, covalently coupled to ImmunoCAP, reacts with tryptase in the patient sample. After washing, enzyme labeled antibodies against tryptase are added to form a complex. After incubation, unbound enzyme-anti-tryptase is washed away and the bound complex is then incubated with a developing agent. After stopping the reaction, the fluorescence of the eluate is measured. The higher the response value, the more tryptase is present in the sample. To evaluate the test results, the responses of the patient samples are transformed into concentrations with the use of a calibration curve.
{4}
M. Performance Characteristics:
1. Analytical performance:
All results below fulfilled the manufacturer's pre-determined acceptance criteria.
a. Precision/Reproducibility:
Phadia 100
Eighteen serum samples with tryptase levels covering the Analytical Measuring Range (AMR) were assayed on three different Phadia 100 instruments. Samples were run in replicates of four on seven different days within a period of 21 days. The results of the study are displayed in the following table:
| Sample | N | Mean (ug/L) | Within-Run (%CV) | Between-Run (%CV) | Between-Instrument (%CV) | Total (%CV) |
| --- | --- | --- | --- | --- | --- | --- |
| 1 | 84 | 1.9 | 2.9 | 2.0 | 2.8 | 4.5 |
| 2 | 84 | 2.8 | 2.6 | 2.3 | 2.6 | 4.4 |
| 3 | 84 | 3.3 | 2.5 | 2.2 | 3.1 | 4.6 |
| 4 | 84 | 4.0 | 1.6 | 3.9 | 0.5 | 4.3 |
| 5 | 84 | 5.0 | 1.8 | 1.6 | 2.3 | 3.4 |
| 6 | 84 | 7.3 | 1.9 | 2.3 | 1.1 | 3.1 |
| 7 | 84 | 10.4 | 1.5 | 1.7 | 1.0 | 2.4 |
| 8 | 84 | 10.6 | 1.9 | 3.1 | 1.0 | 3.8 |
| 9 | 84 | 17.9 | 1.7 | 2.0 | 0.0 | 2.6 |
| 10 | 84 | 19.6 | 1.9 | 2.1 | 0.0 | 2.9 |
| 11 | 84 | 20.5 | 2.7 | 2.2 | 0.0 | 3.5 |
| 12 | 84 | 35.7 | 1.6 | 3.2 | 0.0 | 3.6 |
| 13 | 84 | 36.7 | 3.4 | 3.1 | 0.0 | 4.6 |
| 14 | 84 | 60.8 | 1.8 | 2.9 | 0.0 | 3.4 |
| 15 | 84 | 137.8 | 2.2 | 3.3 | 0.0 | 4.0 |
| 16 | 84 | 151.2 | 2.6 | 2.8 | 1.0 | 3.9 |
| 17 | 84 | 167.1 | 2.3 | 3.3 | 0.0 | 4.0 |
| 18 | 84 | 168.1 | 2.6 | 3.5 | 0.6 | 4.4 |
{5}
Phadia 250
Twenty one serum samples with different tryptase levels covering the AMR were assayed on three different Phadia 250 instruments. The results of the study are displayed in the following table:
| Sample | N | Mean (ug/L) | Within-Run (%CV) | Between-Run (%CV) | Between-Instrument (%CV) | Total (%CV) |
| --- | --- | --- | --- | --- | --- | --- |
| 1 | 84 | 1.7 | 2.3 | 5.6 | 3.2 | 6.9 |
| 2 | 84 | 2.3 | 2.4 | 5.2 | 2.2 | 6.1 |
| 3 | 84 | 2.7 | 2.7 | 5.2 | 1.7 | 6.1 |
| 4 | 84 | 3.5 | 3.4 | 5.8 | 0.0 | 6.7 |
| 5 | 84 | 3.6 | 2.3 | 4.4 | 1.1 | 5.1 |
| 6 | 84 | 6.8 | 1.7 | 4.4 | 0.0 | 4.7 |
| 7 | 84 | 10.3 | 2.6 | 4.7 | 1.0 | 5.4 |
| 8 | 84 | 11.9 | 2.1 | 3.5 | 1.3 | 4.3 |
| 9 | 84 | 16.8 | 2.3 | 5.1 | 1.0 | 5.7 |
| 10 | 84 | 18.1 | 1.6 | 4.3 | 1.1 | 4.7 |
| 11 | 84 | 19.8 | 2.2 | 4.6 | 0.0 | 5.1 |
| 12 | 84 | 22.3 | 2.1 | 4.5 | 2.4 | 5.5 |
| 13 | 84 | 36.6 | 2.1 | 4.5 | 1.1 | 5.1 |
| 14 | 84 | 63.2 | 2.2 | 5.7 | 2.9 | 6.7 |
| 15 | 84 | 76.3 | 2.4 | 6.1 | 1.1 | 6.7 |
| 16 | 84 | 115.9 | 3.1 | 6.3 | 3.3 | 7.7 |
| 17 | 84 | 122.7 | 3.4 | 7.1 | 2.4 | 8.2 |
| 18 | 84 | 133.6 | 3.3 | 7.2 | 3.9 | 8.8 |
| 19 | 84 | 161.0 | 4.6 | 6.9 | 2.7 | 8.8 |
| 20 | 84 | 168.1 | 4.1 | 7.4 | 0.7 | 8.5 |
| 21 | 84 | 171.4 | 4.9 | 6.3 | 0.0 | 8.0 |
## Lot-to-lot Reproducibility
Ten serum samples with tryptase concentrations covering the AMR of the assay were assayed using three different lots of reagent that included the updated ImmunoCAP Tryptase Conjugate, the updated ImmunoCAP Tryptase Calibrators and the
{6}
ImmunoCAP Tryptase Anti-Tryptase. The conjugate, calibrators and anti-Tryptase lots were combined into six different combinations. Each sample was tested in replicates of three, with each of the six combinations in three assay runs, for a total of 54 measurements per sample. The results of the study are displayed in the following table:
| Sample | N | Mean (μg/L) | Within-run (%CV) | Between -lot (%CV) | Between-run (%CV) | Total (%CV) |
| --- | --- | --- | --- | --- | --- | --- |
| 1 | 54 | 2.8 | 4.6 | 4.5 | 0.0 | 6.4 |
| 2 | 54 | 3.4 | 3.5 | 2.5 | 0.0 | 4.3 |
| 3 | 54 | 7.5 | 3.1 | 1.8 | 1.9 | 4.0 |
| 4 | 54 | 10.5 | 2.5 | 2.5 | 1.9 | 4.0 |
| 5 | 54 | 16.9 | 2.7 | 1.3 | 1.1 | 3.2 |
| 6 | 54 | 19.4 | 2.8 | 2.4 | 1.4 | 4.0 |
| 7 | 54 | 33.6 | 3.6 | 1.0 | 3.1 | 4.8 |
| 8 | 54 | 136.6 | 4.8 | 4.1 | 4.0 | 7.5 |
| 9 | 54 | 159.4 | 5.5 | 3.4 | 0.8 | 6.5 |
| 10 | 54 | 162.0 | 5.8 | 1.3 | 4.0 | 7.2 |
b. Linearity/assay reportable range:
Three serum samples with tryptase concentrations between 160 – 200 μg/L were diluted in 2-fold direct dilutions in the ImmunoCAP IgE/ECP/Tryptase sample diluent. Samples (undiluted and diluted) were analysed in replicates of four in one assay run on the Phadia 100 and Phadia 250 instruments.
Phadia 100 Regression Analysis
| Sample | Slope (95% CI) | Y-intercept (95% CI) | r2 |
| --- | --- | --- | --- |
| 1 | 0.99 (0.97–1.02) | -0.75 (-2.62–1.11) | 0.9993 |
| 2 | 1.02 (0.97–1.06) | 0.22 (0.97–1.06) | 0.9981 |
| 3 | 0.99 (0.96–1.03) | -1.23 (0.96–1.03) | 0.9987 |
Phadia 250 Regression Analysis
| Sample | Slope (95% CI) | Y-intercept (95% CI) | r2 |
| --- | --- | --- | --- |
| 1 | 0.99 (0.95–1.03) | -1.11 (-3.97–1.75) | 0.9983 |
| 2 | 1.01 (0.97–1.06) | 0.76 (-2.85–4.38) | 0.9981 |
| 3 | 1.00 (0.98–1.01) | -0.38 (-1.32–0.57) | 0.9998 |
{7}
c. Traceability, Stability, Expected values (controls, calibrators, or methods):
## Traceability
There is no internal standard for tryptase. ImmunoCAP Tryptase calibrators and ImmunoCAP Tryptase Curve Control is prepared from recombinant tryptase protein. The recombinant tryptase is expressed in Sf9 insect cells infected with recombinant baculovirus coding for mast-cell tryptase. The original reference standard was produced in-house. New in-house reference standard is produced from the stock solutions approximately every 3rd year. Each subsequent lot is standardized against the original reference standard.
## Stability
Calibrator stability: Calibrator stability was evaluated using three different lots. For the calibrator strip, one lot of ImmunoCAP Tryptase Calibrator strip was first transport simulated and then stored at $32^{\circ}\mathrm{C}$ for 28 days to evaluate on-board reagent stability. Following this, time zero measurement with two additional calibrator lots were performed. All three calibrator lots were stored at $2^{\circ} - 8^{\circ}\mathrm{C}$. The three lots were tested at five different test occasions up to 25 months. The results support an on-board stability claim of 28 days and a real-time stability claim of 25 months when calibrators are stored at $2 - 8^{\circ}\mathrm{C}$.
Conjugate Stability: To simulate transport stability, one lot of ImmunoCAP Tryptase Conjugate 50 was stored at $32^{\circ}\mathrm{C}$ for one week. During this time the conjugates were moved to $2 - 8^{\circ}\mathrm{C}$ twice for 18-24 hours and moved once to $-20^{\circ}\mathrm{C}$ for 2-3 hours. Following transport simulation, the conjugate was left on board for 4 days at $2 - 8^{\circ}\mathrm{C}$, and were recapped every night. After the initial time zero measurements, all three lots were stored at $2 - 8^{\circ}\mathrm{C}$ and stability was measured at four additional time points up to 25 months. The results support an onboard stability claim of four days when stored on the Phadia 250, and real-time stability claim of 25 months when stored at $2 - 8^{\circ}\mathrm{C}$.
## d. Detection limit:
The LoB was determined using five tryptase free serum sample. Samples were tested in replicates of four, in three separate runs, during three days, with two different lots of reagents (ImmunoCAP Tryptase Conjugate, ImmunoCAP, Tryptase Calibrators and ImmunoCAP Tryptase Anti-Tryptase) for a total 60 blank determinations. The LoB was estimated from Relative Units (RU) as the maximum value for reagent lot-specific LoB estimates. The LoB was determined to be less than $1\mu \mathrm{g} / \mathrm{L}$.
The LoD was determined by measuring five low positive samples ranging from LoB to 5x LoB. Also, the lowest tryptase calibrator $(1\mu \mathrm{g} / \mathrm{L})$ was assayed as a sample. Each sample was assayed in replicates of four, in three separate runs, for three days, with two different lots of reagents (ImmunoCAP Tryptase Conjugate, ImmunoCAP Tryptase Calibrators and ImmunoCAP Tryptase Anti-Tryptase) for a total of 60 low
8
{8}
positive determinations. Calculation of LoD was made on Response Units (RU) because no tryptase concentrations are calculated below the lowest calibrator. The LoD was determined to be less than $1\ \mu\mathrm{g}/\mathrm{L}$ ($1\ \mu\mathrm{g}/\mathrm{L}$ is the lowest calibrator in the kit). The data is presented in the table below:
| Instrument | Mean Calibrator 1 (RU) | LoB (RU) | LoD (RU) |
| --- | --- | --- | --- |
| Phadia 100 | 250 | 89 | 116 |
| Phadia 250 | 284 | 83 | 109 |
e. Analytical specificity:
Studies were performed in alignment with CLSI EP07-A2: Interference Testing in Clinical Chemistry; Approved Guideline - Second Edition. Three serum samples with different concentrations of tryptase; approximately $4\ \mu\mathrm{g}/\mathrm{L}$, $18\ \mu\mathrm{g}/\mathrm{L}$ and $140\ \mu\mathrm{g}/\mathrm{L}$ were used. Serum samples were spiked with five different concentrations of potentially interfering substances. Bilirubin F (up to $19.4\ \mathrm{mg/dl}$), Bilirubin C (up to $20.3\ \mathrm{mg/dl}$), Hemoglobin (up to $490\ \mathrm{mg/dl}$), Chyle (up to 7160 FTU), Rheumatoid Factor (up to $500\ \mathrm{IU/ml}$), and Heparin (up to $75\ \mathrm{U/ml}$) were used to spike serum samples. For reference, the serum samples were diluted with the same volume of buffer solution (unspiked). For Heparin, the untreated serum samples were used as reference (unspiked). The samples were analyzed in 3 replicates in one assay run. No significant interference at the tested levels was observed.
f. Assay cut-off:
The cut-off of $20\ \mu\mathrm{g}/\mathrm{L}$ of tryptase is internationally recognized and is designated by the World Health Organization (WHO) as a minor criterion in the diagnosis of systemic mastocytosis. The WHO classification for systemic mastocytosis is described in the "WHO classification of tumours of haematopoietic and lymphoid tissues" published in 2008.
g. Hook-effect:
Hook effect was evaluated by comparing the response of a serum sample with a tryptase concentration of $2000\ \mu\mathrm{g}/\mathrm{L}$ with the response of the highest calibrator, which is at concentration of $200\ \mu\mathrm{g}/\mathrm{L}$, and ensuring that the response level of the high sample was clearly above the highest calibrator. The hook sample and the highest calibrator were assayed in 24 replicates respectively in one assay run in the Phadia 100 and 250 instruments. No hook effect was observed.
{9}
# 2. Comparison studies:
# a. Method comparison with predicate device:
Comparison between the updated ImmunoCAP Tryptase and predicate ImmunoCAP Tryptase (K103039) was performed with 275 serum samples with tryptase levels across the analytical measuring range of the device. Passing-Bablock regression analysis and $95\%$ confidence intervals (CI) for the intercept and slope were estimated for all samples and all samples excluding healthy individuals.
| Comparison | Slope (95% CI) | y-intercept (95% CI) |
| --- | --- | --- |
| All | 0.948 (0.94–0.95) | 0.418 (0.35–0.48) |
| Excluding Healthy Individuals | 0.959 (0.94–0.98) | -0.13 (-0.06–0.25) |
# b. Instrument comparison between Phadia 100 and Phadia 250:
Conformity between the Phadia 250 and Phadia 100 instruments for the updated ImmunoCAP Tryptase using 69 serum samples with tryptase concentrations covering the measuring range. Samples were assayed in one replicate in two assay runs on three different Phadia 100 and three different Phadia 250 instruments, for six runs/instrument system. Passing-Bablok regression analysis was used to evaluate the bias between tryptase measurements from both instruments. The results are presented in the table below:
| Comparison | Slope (95% CI) | y-intercept (95% CI) |
| --- | --- | --- |
| Phadia 250 vs Phadia 100 | 0.92 (0.91–0.94) | 0.12 (-0.07–0.57) |
# c. Matrix comparison:
Twenty-five patient samples containing different levels of tryptase ranging from approximately $4 - 190~\mu \mathrm{g / L}$ , were used in the study. The matrices compared were: serum, EDTA plasma, lithium heparin plasma and sodium heparin plasma. All samples matrices from each patient were tested in replicates of two in one assay run. Passing-Bablok regression analysis was used to analyze data. The results are presented in the table below:
{10}
| Comparison | Slope (95% CI) | Intercept (95% CI) |
| --- | --- | --- |
| EDTA vs. Li Heparin | 1.02 (0.95–1.05) | -0.48 (-1.37–0.33) |
| EDTA vs. Na Heparin | 0.98 (0.95–1.02) | 0.15 (-0.79–0.63) |
| EDTA vs Serum | 0.98 (0.92–1.05) | -0.02 (-0.51–2.19) |
| Li Heparin vs Na Heparin | 0.97 (0.93–1.01) | 0.48 (-0.30–1.11) |
| Li Heparin vs Serum | 0.98 (0.93–1.03) | 0.44 (-0.27–1.87) |
| Na Heparin vs Serum | 1.00 (0.94–1.06) | 0.21 (-0.71–1.61) |
3. Clinical studies:
a. Clinical Sensitivity and Specificity:
Clinical performance of the ImmunoCAP Tryptase assay was evaluated at two independent sites:
Site 1:
The study was performed with samples collected from 84 patients with a suspicion of mastocytosis. 77 subjects were adults (>22 years of age) and 7 subjects were pediatric patients (<22 years of age). All patients were referred to the site due to a suspicion of mastocytosis and other mast cell-related diseases on the basis of clinical symptoms attributable to mast cell activation (MCA) including anaphylaxis. Patients were classified with and without the WHO recommended fourth minor criterion of tryptase levels persistently exceeding 20 µg/L.
| ImmunoCAP
Tryptase Assay
(cut-off > 20
μg/L ) | + | - | Total |
| --- | --- | --- | --- |
| + | 37 | 4 | 41 |
| - | 19 | 24 | 43 |
| Total | 56 | 28 | 84 |
Sensitivity = 66.1% (95% CI: 52.2–78.2)
Specificity = 85.7% (95% CI: 67.3–96.0)
PPV = 90.2% (95% CI: 76.9–96.0)
NPV = 55.8% (95% CI: 39.9–70.9)
{11}
12
| | WHO Classification excluding tryptase | | | |
| --- | --- | --- | --- | --- |
| | | + | - | Total |
| ImmunoCAP
Tryptase Assay
(cut-off > 20 μg/L) | + | 32 | 9 | 41 |
| | - | 19 | 24 | 43 |
| | Total | 51 | 33 | 84 |
Sensitivity = 62.7% (95% CI: 48.1–75.9)
Specidficity = 72.7% (95% CI: 54.5–86.7)
PPV = 78.0% (95% CI: 62.4–89.4)
NPV = 55.8% (39.9–70.9)
## Site 2:
The study was performed with samples from 54 patients with a suspicion of mastocytosis. 42 subjects were adults (≥ 22 years of age) and 12 were pediatric patients (< 22 years of age). All cases were consecutively referred due to the suspicion of mastocytosis or mast cell activation syndrome based primarily on clinical symptoms attributed to MCA, including anaphylaxis, a characteristic skin lesion or lesional skin biopsy, a bone marrow biopsy or an elevated baseline serum tryptase level. Patients were classified with and without the WHO recommended fourth minor criterion of tryptase levels persistently exceeding 20 μg/L.
| | WHO Classification including tryptase | | | |
| --- | --- | --- | --- | --- |
| | | + | - | Total |
| ImmunoCAP
Tryptase Assay
(cut-off > 20 μg/L) | + | 15 | 3 | 18 |
| | - | 10 | 26 | 36 |
| | Total | 25 | 29 | 54 |
Sensitivity = 76.2% (95% CI: 52.8–91.8)
Specificity = 66.7% (95% CI: 48.2–82.0)
PPV = 59.3% (95% CI: 76.938.8–77.6)
NPV = 81.5% (95% CI: 61.9–93.7)
{12}
13
| | WHO Classification excluding tryptase | | | |
| --- | --- | --- | --- | --- |
| | | + | - | Total |
| ImmunoCAP
Tryptase Assay
(cut-off > 20 μg/L) | + | 15 | 3 | 18 |
| | - | 10 | 26 | 36 |
| | Total | 25 | 29 | 54 |
Sensitivity = 75.0% (95% CI: 50.9–91.3)
Specificity = 64.7% (95% CI: 46.5–80.3)
PPV = 55.6% (95% CI: 35.3–74.5)
NPV = 81.5% (95% CI: 61.9–93.7)
c. Other clinical supportive data (when a. and b. are not applicable):
Not applicable.
4. Clinical cut-off:
Not applicable
5. Expected values/Reference range:
Serum samples from 163 healthy individuals between 1–68 years of age were analyzed in duplicates on both the Phaida 100 and Phadia 250 instruments. Of these 70 were males 0–68 years of age (median age 29), and 93 were females 1–68 years of age (median age 40). Pediatric samples (below the age of 22) comprised 68 individuals in the test population, with an age range of 1–17 years (M=29 and F=39). The results are presented in the table below:
All healthy Individuals
| Instrument | Mean (μg/L) | 95^{th} Percentile (μg/L) | Number of Individuals |
| --- | --- | --- | --- |
| Phadia 100 | 3.8 | 8.2 | 163 |
| Phadia 250 | 3.5 | 8.4 | 163 |
Adults Only
| Instrument | Mean (μg/L) | 95^{th} Percentile (μg/L) | Number of Individuals |
| --- | --- | --- | --- |
| Phadia 100 | 4.7 | 9.9 | 95 |
| Phadia 250 | 4.4 | 8.9 | 95 |
{13}
14
Pediatrics Only (<22 years old)
| Instrument | Mean (μg/L) | 95^{th} Percentile (μg/L) | Number of Individuals |
| --- | --- | --- | --- |
| Phadia 100 | 2.8 | 6.4 | 68 |
| Phadia 250 | 2.4 | 6.3 | 68 |
N. Proposed Labeling:
The labeling is sufficient and it satisfies the requirements of 21 CFR Parts 801 and 809, as applicable
O. Conclusion:
1. The submitted information in this premarket notification is complete and supports a substantial equivalence decision.
Predicate graph will load when search results are available.
Embedding visualization will load when search results are available.
PDF viewer will load when search results are available.
Loading panels...
Select an item from Submissions
Click any panel, subpart, regulation, product code, or device to see details here.
Section Matches
Results will appear here.
Product Code Matches
Results will appear here.
Special Control Matches
Results will appear here.
Loading collections...
Loading
My Alerts
You will receive email notifications based on the filters and frequency you set for each alert.
Sort by:
Create Alert
Search Filters
Agent Token
Create a read-only bearer token for Claude, ChatGPT, or other agents that can call HTTP APIs.
Copy this now. It will not be shown again.
Connected apps
Apps you authorized through browser sign-in. Disconnecting revokes their access immediately.
Learn the FDA Browser
Two short videos show you everything — or skip straight to the written tutorial if you'd rather read. You can reopen this any time from the Tutorial button in the top bar.
Part 1 — Search, results, and everyday workflows 16 min
Part 2 — Embeddings: the galaxy map 3 min
1. Search: exact and fuzzy
Type a phrase like "coronary artery calcification" into the search box. You get two kinds of results. Exact results match the literal phrase — prefix searches work ("coronary artery calcificati") but suffix searches do not. Fuzzy results match on the meaning and intent of your phrase rather than the exact words, and are sorted by relevance score. Hover over the Exact or Fuzzy badge on any row to see exactly why it matched.
Use the checkboxes above the results to narrow: SaMD keeps only software-only devices, AI / ML keeps only devices with AI.
Exact vs. fuzzy search: what's the difference?
Exact matches on the literal phrase (prefix search works, suffix does not). Fuzzy matches on the meaning and intent of the phrase rather than the exact words. Hover over the badge on any row to see why it matched.
You search "coronary artery calcification" and want only software devices with AI. What two filters do you apply?
Narrow by SaMD (software-only devices), then narrow by AI/ML (devices with AI).
2. The results table
Scroll right in the results table. The intended use is extracted for you — no need to open the PDF. The device story gives a high-level snapshot of what the device does and how it's used. The AI Performance sub-table shows each output name, acceptance criteria, observed values, and development/test dataset descriptions — the same format Innolitics uses for regulatory strategy outputs, and the fastest high-level fingerprint of an AI device. It is AI-generated but has been very reliable in practice.
Where do you find a device's intended use without opening the PDF?
Scroll right in the search results table. The intended use column is extracted for you; no need to dig into the 510(k) summary PDF.
What does the AI Performance sub-table show, and why is it useful?
Output name, acceptance criteria, observed values, development dataset description, and test dataset description. It's the same format we use for regulatory strategy output and Fast 510(k) input, and the fastest high-level fingerprint of an AI device. AI-generated but reliable in practice.
3. Judging fuzzy relevance
Fuzzy results trail off in relevance as you scroll. Use three signals to decide how far down to go: the fuzzy badge explanations, the intended use column, and whether your target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, you're past the relevant zone. A top hit with a low score (~0.4) and a stretched explanation is a hint the closest predicates are far away — the project may be headed for De Novo. Note the fuzzy search is a pattern match: it doesn't handle negation ("not") well, and hardware devices can appear — filter by SaMD/AI ML to cut them.
How do you judge how far down fuzzy search results to go?
Use the relevancy signals: the fuzzy badge explanations, the intended use column, and whether the target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, results are trailing off in relevancy.
4. Device detail page: chat and citations
Click a device name to open its detail page: device facts on the left, a chat window on the right. Ask something like "Describe the training data". The answer carries little citation bubbles — click one to jump to the highlighted passage in the source PDF, so you can verify every AI answer against the document. There's also a Download PDF button for sharing.
How do you verify an AI chat answer on the device detail page?
Click the citation bubbles to jump to the relevant highlight in the source document.
Reading rule for every project: how many summaries do you read in full?
At least the three most relevant 510(k) or De Novo summaries, in full. After that, use targeted chat questions to confirm your memory quickly. The tool supports this professional habit — it doesn't replace it.
5. Side-by-side comparison
Select multiple rows in the results table (aim for under ~10), then open the PDF Viewer tab. Ask one question — it goes to all selected devices in parallel, each with citations. This is the fastest way to compare and contrast devices: training data, PCCP scope, how they handled adding new scanners, and so on.
What does the side-by-side PDF viewer mode do?
Select multiple devices, open the PDF viewer tab, and ask one question (e.g., "Describe the training data"). It queries all selected devices simultaneously with citations, so you can compare and contrast quickly.
6. Collections
With rows selected, go to the Collections tab and create a labeled collection (e.g., "Cobb Angle Project"). Reload that selection any time — before a client call, pull up the collection and ask questions across all of its devices at once.
How do you save a set of selected devices for later use?
Select the rows, go to the Collections tab, and create a labeled collection (e.g., "Cobb Angle Project"). You can reload the selection anytime and carry it into the PDF viewer and other tabs that support selections.
7. Product codes and the regulations tree
Click a product code in the results to jump to it in the regulations tree — identification text, sibling product codes, and devices you can open in a PDF viewer on the right. Click a regulation number to see its identification, special controls, and related product codes. You can also search by product code or regulation number at the top of the tree. Always read the special controls if any exist for your device — it broadens your search and sharpens pre-kickoff research.
What can you do from the regulations tree view?
Browse product codes and regulation numbers, read the identification text and special controls, browse sibling product codes, open device PDFs on the right, and search by product code or regulation number at the top of the tree.
8. Chart view
Click Show Chart and segment by regulation number (or product code) to see which regulations dominate your result set. Clicking a regulation takes you into the regulations tree. Great for spotting that most matches are, say, hardware laparoscopic devices — a cue to go back and filter.
How do you see which regulations dominate a search result set?
Click "Show Chart" and segment by Regulation Number. Clicking a regulation takes you to the regulations tree.
9. The predicate graph
Open the Predicates tab for a family-tree view of predicate relationships. Click a node to trace its parents and children; selections from search carry over pre-selected. Commonly predicated devices are worth reading — a lot of people predicated them for a reason. The visual lineage is also handy on client calls, e.g. to show how a predicate family evolved and justify why your predicate still holds.
In the predicate graph, why are commonly predicated devices worth reading?
A lot of people predicated them for a reason. Clicking a node traces parents and children, and selections from search carry over pre-selected.
10. Embeddings: the galaxy map
The Embeddings tab plots every matching document in a 2-D "galaxy map" where semantically similar devices cluster together. Hover or click clusters to explore, and let AI label the clusters for you. Embeddings beat product codes for grouping: two devices can carry different product codes (LLZ vs. QIH) yet do the same thing — the embedding captures the meaning of the intended use and device story. This is also exactly how retrieval-augmented generation (RAG) works under the hood, and it makes a great visual on client calls.
Try it yourself
Head to the search page and work through a few of these AI/ML fuzzy searches to build intuition: perivascular fat on CT · aortic valve calcification opportunistic screening on noncontrast CT · breast cancer prediction on digital pathology slides · autism detection · gestational age prediction · a hearing aid that can also detect a pulse · foundation model based analysis of ECG · large language models · penetration test. Watch how the relevance scores, intended use, and AI Performance tables tell you when results stop being meaningful.