Elecsys BRAHMS PCT
Device Facts
| Record ID | K173927 |
|---|---|
| Device Name | Elecsys BRAHMS PCT |
| Applicant | Roche Diagnostics |
| Product Code | PRI · Microbiology |
| Decision Date | Jul 6, 2018 |
| Decision | SESE |
| Submission Type | Traditional |
| Regulation | 21 CFR 866.3215 |
| Device Class | Class 2 |
| Attributes | Real-World Evidence |
Real-World Evidence
| Submission | Device | Sponsor | RWD Sources | RWE Use Summary | Key Tags |
|---|---|---|---|---|---|
| K173927 · Jul 6, 2018 | Elecsys BRAHMS PCT | Roche Diagnostics | Retrospective clinical specimens (frozen samples) from the BRAHMS MOSES study | Retrospective clinical samples were used to perform a clinical concordance analysis comparing the candidate device to the predicate device across various medical decision points. | Retrospective clinical specimens; Clinical concordance; BRAHMS MOSES study |
Clinical Evidence
| Study Design | Population | Comparator | Key Endpoints |
|---|---|---|---|
| BRAHMS MOSES study; Retrospective clinical concordance study | Adult patients (>18 years) diagnosed with severe sepsis or septic shock; Sample Size: 2617; Number of Sites: Multicenter | BRAHMS PCT sensitive Kryptor (predicate device) | Clinical concordance at medical decision points (0.1, 0.25, 0.5, and 2.0 ng/mL) |
Indications for Use
Immunoassay for the in vitro quantitative determination of PCT (procalcitonin) in human serum and plasma (K2 –EDTA, K3-EDTA and Li-Heparin). The electrochemiluminescence immunoassay “ECLIA” is intended for use on Elecsys and cobas e immunoassay analyzers. Used in conjunction with other laboratory findings and clinical assessments, Elecsys BRAHMS PCT is intended for use as follows: - to aid in the risk assessment of critically ill patients on their first day of ICU admission for progression to severe sepsis and septic shock, - to determine the change in PCT level over time as an aid in assessing the cumulative 28-day risk of all-cause mortality for patients diagnosed with severe sepsis or septic shock in the ICU or when obtained in the emergency department or other medical wards prior to ICU admission, - to aid in decision making on antibiotic therapy, for inpatients or patients in the emergency department with suspected or confirmed lower respiratory tract infections (LRTI) – defined as community-acquired pneumonia (CAP), acute bronchitis, and acute exacerbation of chronic obstructive pulmonary disease (AECOPD), - to aid in decision making on antibiotic discontinuation for patients with suspected or confirmed sepsis.
Device Story
Elecsys BRAHMS PCT is an in vitro diagnostic immunoassay for quantitative measurement of procalcitonin (PCT) in human serum/plasma; used on Elecsys and cobas e analyzers. Device utilizes two-step sandwich immunoassay principle with biotinylated and ruthenium-labeled monoclonal antibodies; streptavidin-coated microparticles capture the sandwich complex. Electrochemiluminescence detection system measures light emission proportional to PCT concentration. Operated by laboratory personnel in clinical settings. Output provides numerical PCT values used by clinicians alongside other laboratory/clinical assessments to guide antibiotic therapy initiation/discontinuation and assess sepsis progression/mortality risk. Benefits include standardized, automated risk stratification for septic patients.
Clinical Evidence
Retrospective multicenter study (n=2617) of adult patients with severe sepsis or septic shock. Compared Elecsys BRAHMS PCT to predicate (KRYPTOR). Results showed >97% total agreement at medical decision points (0.1, 0.25, 0.5, 2.0 ng/mL). Passing-Bablok slope 0.959 (95% CI: 0.947-0.972); intercept -0.023. Pearson correlation 0.989. Precision studies (CLSI EP5-A3) showed intermediate precision CVs ranging from 2.2% to 24.3% across the measuring range.
Technological Characteristics
Two-step sandwich immunoassay; electrochemiluminescence detection. Reagents: streptavidin-coated microparticles, biotinylated monoclonal anti-PCT antibody, ruthenium-labeled monoclonal anti-PCT antibody. Measuring range: 0.02–100 ng/mL. Instrument: cobas e 411. Connectivity: barcode-based master curve calibration. Standards: CLSI EP05-A3, EP06-A, EP17-A2.
Indications for Use
Indicated for critically ill patients (adults >18 years) with suspected or confirmed sepsis, septic shock, or lower respiratory tract infections (CAP, acute bronchitis, AECOPD) to aid in risk assessment, mortality risk stratification, and antibiotic therapy management. Prescription use only.
Regulatory Classification
Identification
A device to detect and measure non-microbial analyte(s) in human clinical specimens to aid in assessment of patients with suspected sepsis is identified as an in vitro device intended for the detection and qualitative and/or quantitative measurement of one or more non-microbial analytes in human clinical specimens to aid in the assessment of patients with suspected sepsis when used in conjunction with clinical signs and symptoms and other clinical and laboratory findings.
Special Controls
A device to detect and measure non-microbial analyte(s) in human clinical specimens to aid in assessment of patients with suspected sepsis must comply with the following special controls:
*Classification.* Class II (special controls). The special controls for this device are:(1) Premarket notification submissions must include the device's detailed Indications for Use statement describing what the device detects and measures, the results provided to the user, whether the measure is qualitative and/or quantitative, the clinical indications for which the test is to be used, and the specific population(s) for which the device use is intended. (2) Premarket notification submissions must include detailed documentation of the device description, including (as applicable), all device components, software, ancillary reagents required but not provided, explanation of the device principle and methodology, and for molecular devices include detailed documentation of the primer/probe sequence, design, and rationale for sequence selection. (3) Premarket notification submissions must include detailed documentation of applicable analytical studies, such as, analytical sensitivity (Limit of Detection, Limit of Blank, and Limit of Quantitation), precision, reproducibility, analytical measuring range, interference, cross-reactivity, and specimen stability. (4) Premarket notification submissions must include detailed documentation of a prospective clinical study or, if appropriate, results from an equivalent sample set. This detailed documentation must include the following information: (i) Results must demonstrate adequate device performance relative to a well-accepted comparator. (ii) Clinical sample results must demonstrate consistency of device output throughout the device measuring range likely to be encountered in the Intended Use population. (iii) Clinical study documentation must include the original study protocol (including predefined statistical analysis plan), study report documenting support for the Indications for Use(s), and results of all statistical analyses. (5) Premarket notification submissions must include evaluation of the level of the non-microbial analyte in asymptomatic patients with demographic characteristics ( *e.g.,* age, racial, ethnic, and gender distribution) similar to the Intended Use population.(6) As part of the risk management activities performed under 21 CFR 820.10(c) design and development, you must document an appropriate end user device training program that will be offered as part of your efforts to mitigate the risk of failure to correctly operate the instrument. (7) A detailed explanation of the interpretation of results and acceptance criteria must be included in the device's 21 CFR 809.10(b)(9) compliant labeling, and a detailed explanation of the interpretation of the limitations of the samples ( *e.g.,* collected on day of diagnosis) must be included in the device's 21 CFR 809.10(b)(10) compliant labeling.
Predicate Devices
- BRAHMS PCT sensitive KRYPTOR (K171338)
Submission Summary (Full Text)
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# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION
DECISION SUMMARY
A. 510(k) Number:
K173927
B. Purpose for Submission:
To obtain a substantial equivalence determination for the Elecsys BRAHMS PCT.
C. Measurand:
Procalcitonin (PCT)
D. Type of Test:
Quantitative, Electrochemiluminescence Immunoassay
E. Applicant:
Roche Diagnostics
F. Proprietary and Established Names:
Elecsys BRAHMS PCT
G. Regulatory Information:
1. Regulation section:
21 CFR 866.3215; Device to detect and measure non-microbial analyte(s) in human clinical specimens to aid in assessment of patients with suspected sepsis
2. Classification:
Class II (Special Controls)
3. Product codes:
PMT
4. Panel:
83 - (Microbiology)
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## **H. Intended Use/ Indications for Use:**
### **1. Intended Use/ Indications for Use:**
Immunoassay for the in vitro quantitative determination of PCT (procalcitonin) in human serum and plasma (K2 –EDTA, K3-EDTA and Li-Heparin).
The electrochemiluminescence immunoassay “ECLIA” is intended for use on Elecsys and cobas e immunoassay analyzers.
Used in conjunction with other laboratory findings and clinical assessments, Elecsys BRAHMS PCT is intended for use as follows:
- to aid in the risk assessment of critically ill patients on their first day of ICU admission for progression to severe sepsis and septic shock,
- to determine the change in PCT level over time as an aid in assessing the cumulative 28-day risk of all-cause mortality for patients diagnosed with severe sepsis or septic shock in the ICU or when obtained in the emergency department or other medical wards prior to ICU admission,
- to aid in decision making on antibiotic therapy, for inpatients or patients in the emergency department with suspected or confirmed lower respiratory tract infections (LRTI) – defined as community-acquired pneumonia (CAP), acute bronchitis, and acute exacerbation of chronic obstructive pulmonary disease (AECOPD),
- to aid in decision making on antibiotic discontinuation for patients with suspected or confirmed sepsis.
### **2. Special conditions for use statement(s):**
For prescription use only
#### **Warnings and Precautions:**
The Elecsys BRAHMS PCT assay should not be used as a sole basis for diagnosis for determining the risk of 28 day all-cause mortality. Changes in PCT should always be interpreted in the context of the clinical status of the patient and other laboratory results. There is no uniformly recognized interpretation of the change in PCT levels for the prediction of mortality, and overall mortality is strongly dependent on many factors, including pre-existing patient risk factors and clinical course. The need for continued ICU care at Day 4 and other covariates (e.g., age, sepsis-related organ failure assessment (SOFA score) are also significant predictors of 28-day cumulative mortality risk. Validation of the Elecsys BRAHMS PCT assay as an aid in predicting mortality was performed in a study population with an overall 28-day mortality of 22%.
### **3. Special instrument requirements:**
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The submission demonstrates performance on the cobas e411 immunoassay analyzer.
### I. Device Description:
Reagents
Materials provided in Elecsys BRAHMS PCT:
The reagent working solutions include: Rackpack (kit placed on analyzer)
• M: Streptavidin-coated microparticles
• R1: Anti-PCT-Ab~biotin
• R2: Anti-PCT – Ab~Ru (bpy)
### J. Substantial Equivalence Information:
1. Predicate device name(s):
BRAHMS PCT sensitive KRYPTOR
2. Predicate 510(k) number(s):
K171338
4. Comparison with predicate:
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| Similarities | | |
| --- | --- | --- |
| Item | Candidate Device: Elecsys BRAHMS PCT (K173927) | Predicate Device: BRAHMS PCT sensitive KRYPTOR (K171338) |
| **Intended Use** | Immunoassay for the in vitro quantitative determination of PCT (procalcitonin) in human serum and plasma (K2 –EDTA, K3-EDTA and Li-Heparin). The electrochemiluminescence immunoassay “ECLIA” is intended for use on Elecsys and cobas e immunoassay analyzers. Used in conjunction with other laboratory findings and clinical assessments, Elecsys B·R·A·H·M·S PCT is intended for use as follows: - to aid in the risk assessment of critically ill patients on their first day of ICU admission for progression to severe sepsis and septic shock, - to determine the change in PCT level over time as an aid in assessing the cumulative 28-day risk of all-cause mortality for patients diagnosed with severe sepsis or septic shock in the ICU or when obtained in the emergency department or other medical wards prior to ICU admission, - to aid in decision making on antibiotic therapy, for inpatients or patients in the emergency department with suspected or confirmed lower respiratory tract infections (LRTI) – defined as community-acquired pneumonia (CAP), acute bronchitis, and acute exacerbation of chronic obstructive pulmonary disease (AECOPD), - to aid in decision making on antibiotic discontinuation for patients with suspected or confirmed sepsis. | The BRAHMS PCT sensitive KRYPTOR is an immunofluorescent assay using Time-Resolved Amplified Cryptate Emission (TRACE) technology to determine the concentration of PCT (procalcitonin) in human serum and EDTA or heparin plasma. The BRAHMS PCT sensitive KRYPTOR is intended to be performed on the BRAHMS KRYPTOR analyzer family. Used in conjunction with other laboratory findings and clinical assessments, BRAHMS PCT sensitive KRYPTOR is intended for use as follows: - to aid in the risk assessment of critically ill patients on their first day of ICU admission for progression to severe sepsis and septic shock, - to determine the change in PCT level over time as an aid in assessing the cumulative 28-day risk of all-cause mortality for patients diagnosed with severe sepsis or septic shock in the ICU or when obtained in the emergency department or other medical wards prior to ICU admission, - to aid in decision making on antibiotic therapy, for inpatients or patients in the emergency department with suspected or confirmed lower respiratory tract infections (LRTI) – defined as community-acquired pneumonia (CAP), acute bronchitis, and acute exacerbation of chronic obstructive pulmonary disease (AECOPD), - to aid in decision making on antibiotic discontinuation for patients with suspected or confirmed sepsis. |
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| Differences | | |
| --- | --- | --- |
| Item | Candidate Device: Elecsys BRAHMS PCT (K173927) | Predicate Device: BRAHMS PCT sensitive KRYPTOR (DEN150009) |
| Assay Protocol | The Elecsys BRAHMS PCT assay is a two-step sandwich immunoassay with streptavidin microparticles and an electrochemiluminescence detection system. The test system reagents contain a biotinylated monoclonal PCT-specific antibody and a ruthenium labeled monoclonal PCT-specific antibody. | The BRAHMS PCT sensitive KRYPTOR assay is a homogeneous sandwich immunoassay for detection of PCT in human serum or plasma. The measuring principle is based on Time-Resolved Amplified Cryptate Emission (TRACE) technology, which measures the signal that is emitted from an immunocomplex with time delay. |
| Detection Protocol | Electrochemiluminescent Assay | Time-Resolved Amplified Cryptate Emission (TRACE) |
| Applications | 18-minute application | 19-minute incubation |
| Instrument Platform | cobas e 411 analyzer | BRAHMS KRYPTOR analyzer |
| Sample Volume | 30 μL | 50 μL |
| Sample Type | Human serum and plasma (Li- Heparin, K2/K3 EDTA) | Human serum and plasma (EDTA, heparin) |
| Reagents | • Streptavidin-coated microparticles: • Steptavidin-coated microparticles; preservative • Anti-PCT-Ab~biotin: Biotinylated monoclonal anti-PCT antibody (mouse), phosphate buffer, preservative • Anti-PCT – Ab~Ru(bpy) 2/3+ a monoclonal anti-PCT antibody (mouse) labeled with ruthenium complex, phosphate buffer, preservative | • Cryptate conjugate, cryptate labeled, anti-PCT antibody (polyclonal, sheep), 3.2mL after reconstitution with KRYPTOR Solution 2 • L665 conjugate, XL665 labeled, anti-PCT antibody (monoclonal, mouse), 3.95 mL after reconstitution with KRYPTOR Solution 1 and KRYPTOR Solution 2 • Defibrinated human plasma, for diluting samples above 50 μg/L, ready for use |
| Calibrator | Elecsys PCT CalSet | BRAHMS PCT sensitive KRYPTOR Calibrator |
| Calibration Interval | Calibration must be performed once per reagent lot using fresh reagent (i.e. not more than 24 hours since the reagent kit was registered on the analyzer). Renewed calibration is recommended as follows: • after 8 weeks when using the same reagent lot after 7 days (when using the same reagent kit on the analyzer) as required: e.g. quality control findings outside the specified limits | Before first use of each new BRAHMS PCT sensitive KRYPTOR assay lot, then repeated on a regular basis automatically managed by the BRAHMS PCT sensitive KRYPTOR. |
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| Differences | | |
| --- | --- | --- |
| Item | Candidate Device: Elecsys BRAHMS PCT (K173927) | Predicate Device: BRAHMS PCT sensitive KRYPTOR (DEN150009) |
| Controls | Precicontrol PCT | BRAHMS PCT sensitive KRYPTOR Controls |
| Traceability/Standardization | This method has been standardized against the BRAHMS PCT LIA assay. | Not Provided |
| Reagent Stability | Store at 2-8 °C. Do not freeze. Store the Elecsys reagent kit upright in order to ensure complete availability of the microparticles during automatic mixing prior to use. Stability: • unopened at 2-8 °C: up to the stated expiration date • after opening at 2-8 °C: 12 weeks on the analyzers: 4 weeks | In original shipping containers unopened at 2-8 °C: up to the stated expiration date after opening, onboard at 2-8 °C: 29 days |
| Measuring Range | 0.02 – 100ng/mL | 0.02-50μg/L |
| LoB | 0.015 ng/mL | Not Provided |
| LoD | 0.02 ng/mL | Not Provided |
| LoQ | 0.06 ng/mL | 0.075 μg/L |
| Hook Effect | No hook effect up to 1000ng/mL | N/A |
### K. Standard/Guidance Documents Referenced (if applicable):
- CLSI Guideline EP05-A3 – Evaluation of Precision Performance of Quantitative Measurements and Methods; Approved Guideline; Third Edition.
- CLSI Guideline EP06-A, Evaluation of the Linearity of Quantitative Measurement Procedures: A Statistical Approach; Approved Guideline.
- CLSI EP17-A2 guideline, Protocol for Determination of Limits of Detection and Limits of Quantitation; Approved Guideline; Second Edition.
### L. Test Principle:
The Elecsys BRAHMS PCT assay is a two-step sandwich immunoassay with streptavidin microparticles and an electrochemiluminescence detection system. The test system reagents contain a biotinylated monoclonal PCT-specific antibody and a ruthenium labeled monoclonal PCT-specific antibody.
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Total assay duration: 18 minutes.
- 1st incubation: Antigen in the sample (30 μL), a biotinylated monoclonal PCT-specific antibody, and a monoclonal PCT-specific antibody labeled with a ruthenium complex*) react to form a sandwich complex.
- 2nd incubation: After addition of streptavidin-coated microparticles, the complex becomes bound to the solid phase via interaction of biotin and streptavidin.
- The reaction mixture is aspirated into the measuring cell where the microparticles are magnetically captured onto the surface of the electrode. Unbound substances are then removed. Application of a voltage to the electrode then induces chemiluminescent emission which is measured by a photomultiplier.
- Results are determined via a calibration curve which is instrument specific, generated by 2-point calibration and a master curve provided via the reagent barcode.
### M. Performance Characteristics:
#### 1. Analytical performance:
##### a. Reproducibility/Precision:
The repeatability and intermediate precision studies of the Elecsys BRAHMS PCT assay were conducted using the cobas e 411 analyzer. Studies were performed in accordance with CLSI guideline EP5-A3, “Evaluation of Precision Performance of Quantitative Measurement Methods”. One reagent lot was evaluated.
The precision study was conducted using the study design of 21 days x 2 runs per day x 2 replicates per sample. One (1) instrument was used for the study and calibration was performed according to the Instructions for Use. Aliquots of sixteen (16) human serum samples and two (2) QC samples (PC PCT 1 and PC PCT 2) distributed over the measuring range were assayed in duplicate and randomized order on the cobas e 411 analyzer using one lot of reagent.
Summary of precision results are represented in the table below:
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Table 1: Summary of Precision Results –cobas e 411 analyzer
| Sample | Mean (ng/mL) | Repeatability (CV%) | | Intermediate Precision (CV%) | | % Total Error |
| --- | --- | --- | --- | --- | --- | --- |
| | | Within Run | | Within Lab | | |
| | | SD (ng/mL) | CV% | SD (ng/mL) | CV% | |
| 1 | 0.036 | 0.008 | 21.2 | 0.009 | 24.5 | 60.33 |
| 2 | 0.037 | 0.006 | 16.7 | 0.009 | 24.3 | 57.02 |
| 10 | 0.085 | 0.005 | 6.4 | 0.008 | 9.2 | 22.49 |
| 11 | 0.121 | 0.005 | 4.2 | 0.007 | 6.2 | 14.95 |
| 12 | 0.183 | 0.006 | 3.1 | 0.008 | 4.2 | 10.18 |
| 13 | 0.242 | 0.005 | 2.2 | 0.009 | 3.6 | 8.67 |
| 14 | 0.300 | 0.006 | 2.1 | 0.008 | 2.8 | 6.75 |
| 3 | 0.400 | 0.008 | 2.0 | 0.013 | 3.2 | 7.68 |
| 15 | 0.415 | 0.008 | 1.9 | 0.010 | 2.3 | 5.56 |
| 4 | 1.52 | 0.024 | 1.6 | 0.034 | 2.2 | 5.36 |
| 16 | 2.12 | 0.032 | 1.5 | 0.047 | 2.2 | 5.38 |
| 5 | 2.93 | 0.042 | 1.4 | 0.071 | 2.4 | 5.76 |
| 6 | 26.1 | 0.392 | 1.5 | 0.725 | 2.8 | 6.81 |
| 7 | 44.6 | 0.723 | 1.6 | 1.25 | 2.8 | 6.69 |
| 8 | 64.5 | 1.24 | 1.9 | 1.96 | 3.0 | 7.33 |
| 9 | 97.6 | 1.67 | 1.7 | 2.31 | 2.4 | 5.79 |
| Control 1 | 0.466 | 0.007 | 1.5 | 0.010 | 2.2 | N/A |
| Control 2 | 9.53 | 0.101 | 1.1 | 0.207 | 2.2 | N/A |
Reproducibility/Precision results are acceptable.
### b. Linearity/Assay Reportable Range:
Linearity:
See K160729 for study design and data.
Linearity was confirmed in the range of 0.02 ng/mL to 100 ng/mL, which fulfills the defined specifications. The measuring-range claim for the Elecsys BRAHMS PCT assay is 0.02–100 ng/mL.
Linearity results are acceptable.
Dilution Tests:
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See K160729 for study design and data.
The data shown demonstrate consistent accuracy of recovery with all dilution steps.
The recommended dilution in the Method sheet is 1:4 using PCT-negative human serum or plasma.
c. Traceability, Stability, Expected Values (controls, calibrators, or methods):
See K160729 for study design and data.
d. Limit of Blank:
See K160729 for study design and data.
Based on testing, the highest LoB value is 0.011 ng/mL, which fulfills the specification of LoB: ≤0.015 ng/mL. The claim for LoB is 0.015 ng/mL
e. Limit of Detection:
See K160729 for study design and data.
Based on testing, the highest LoD value was determined to be 0.0181 ng/mL, which fulfills the specification of LoD: ≤0.02 ng/mL. The claim for LoD is 0.02 ng/mL
f. Limit of Quantitation:
See K160729 for study design and data.
Based on testing, the highest LoQ value (meeting the CV% specification) was determined to be 0.045 ng/mL. The claim for LoQ is 0.06 ng/mL.
Table 2: Total Error
| Expected value ng/mL | Elecsys BRAHMS PCT | | |
| --- | --- | --- | --- |
| | % CV | % BIAS | % TE |
| 2.00 | 2.37 | 1.94 | 5.85 |
| 0.50 | 2.40 | 2.17 | 6.13 |
| 0.30 | 3.00 | 2.50 | 7.44 |
| 0.25 | 3.41 | 2.70 | 8.32 |
| 0.15 | 5.38 | 3.7 | 12.57 |
| 0.10 | 8.11 | 5.35 | 18.73 |
| 0.05 | 16.65 | 12.45 | 39.92 |
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# g. Analytical Specificity/Cross-Reactivity:
See K160729 for study design and data.
The Elecsys BRAHMS PCT assay on Elecsys and cobas e analyzers does not show any significant cross-reaction with the following substances, tested with PCT concentrations of approximately 0.4 ng/mL and 1.5 ng/mL (maximum tested concentration):
Table 3: Analytical Specificity/Cross-Reactivity
| Substances | Non-interfering concentration (ng/mL) |
| --- | --- |
| Human katacalcin | 30 |
| Human calcitonin | 10 |
| Human alpha-CGRP* | 10000 |
| Human beta-CGRP | 10000 |
* Calcitonin Gene-Related Peptide
# h. Interfering Substances:
Endogenous Interference:
The effect on quantitation of PCT in the presence of five endogenous interfering substances (Hemoglobin, Biotin, Intralipid, Bilirubin, and Rheumatoid Factor) was tested using one cobas e 411 analyzer. Spiked serum pools were used for testing. For each potential interferent, three human serum samples (containing low, mid, and high concentrations of PCT) were tested.
The following substances evaluated with the Elecsys BRAHMS PCT assay were found not to affect the test performance at concentrations reasonably and consistently found in clinical situations.
Table 4: Endogenous Interference
| Interfering substance | Claim | Maximum Value with No Interference Observed |
| --- | --- | --- |
| Hemoglobin | 900 mg/dL | 1000 mg/dL |
| Biotin | 30 ng/mL | 42 ng/mL |
| Intralipid | 1,500 mg/dL | 2,000 mg/dL |
| Bilirubin | 25 mg/dL | 66 mg/dL |
| Rheumatoid Factor | 1,500 IU/mL | 1,500 IU/mL |
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Table 5: Endogenous Interference: Biotin
| % Bias for samples containing various concentrations of biotin | | | | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Samples PCT concentrations (ng/mL) | Biotin concentration (ng/mL) | | | | | | | | | |
| | 9.6 | 20.4 | 30.0 | 39.6 | 80.4 | 99.6 | 150 | 300 | 600 | 1200 |
| 0.04 | 2.3 | 2.8 | 0.2 | -17.0 | * | -65.7 | * | * | * | * |
| 0.10 | 4.5 | -2.8 | -6.6 | -13.2 | -26.8 | -55.2 | -83.3 | * | * | * |
| 0.13 | 0.5 | -2.8 | -3.1 | -4.8 | -25.1 | -45.8 | -68.4 | * | * | * |
| 0.20 | 1.5 | 0.3 | -8.6 | -11.5 | -38.4 | -50.9 | -75.8 | * | * | * |
| 0.48 | 0.9 | 0.5 | -0.03 | -0.5 | -9.1 | -15.5 | -26.8 | -60.5 | -97.7 | * |
| 1.96 | 3.9 | 3.6 | 1.4 | 0.5 | -8.0 | -12.7 | -24.1 | -60.5 | -92.0 | -97.5 |
* = value below measurable range
### Exogenous Interference:
Fifteen pharmaceutical compounds were spiked into two human serum sample pools of different PCT concentrations. Each serum sample was evaluated both with and without the potential interference substances and tested with the Elecsys BRAHMS PCT assay on the Elecsys 2010 analyzer.
The following substances evaluated with the Elecsys BRAHMS PCT assay were found not to affect the test performance at concentrations reasonably and consistently found in clinical situations.
Table 6: Exogenous Interference
| Interfering substance | Concentration tested (mg/L) | Result |
| --- | --- | --- |
| Cromolyn | 24 | No interference observed |
| Acetaminophen | 200 | No interference observed |
| Acetylsalicylic acid | 652 | No interference observed |
| Alcohol | 4000 | No interference observed |
| Azithromycin | 11.5 | No interference observed |
| Cetirizine HCL | 3.6 | No interference observed |
| Dextromethorphan | 1.4 | No interference observed |
| Ibuprofen | 500 | No interference observed |
| Imipenem | 1180 | No interference observed |
| Levofloxacin | 17.5 | No interference observed |
| Loratadine | 0.3 | No interference observed |
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| Interfering substance | Concentration tested (mg/L) | Result |
| --- | --- | --- |
| Nicotine | 1 | No interference observed |
| Oxymetazoline HCL | 0.09 | No interference observed |
| Phenylephrine | 0.18 | No interference observed |
| Tiotropium | 0.0216 | No interference observed |
See K160729 for additional interference studies.
HAMA Effect:
See K160729 for study design and data.
There was no HAMA interference observed.
i. High-Dose Hook Effect:
There was no observed high-dose hook effect at PCT concentrations up to 1,000 ng/mL PCT.
j. Assay Cut-off:
28-day mortality:
- \(\Delta \mathrm{PCT} \leq 80\%\)
A decrease in the PCT levels below or equal to 80% defines a positive \( \Delta \) PCT test result representing a higher risk for 28-day all-cause mortality of patients diagnosed with severe sepsis or septic shock.
- \(\Delta \mathrm{PCT} > 80\%\)
A decrease in the PCT levels of more than 80% defines a negative \( \Delta \) PCT test result representing a lower risk for 28-day all-cause mortality of patients diagnosed with severe sepsis or septic shock.
NOTE: The combination of the first PCT level ( \( \leq 2.0 \) ng/mL or >2.0 ng/mL) at initial diagnosis of severe sepsis or septic shock with the patient's clinical course and the change in PCT level over time until Day 4 provides important additional information about the mortality risk.
Progression Risk:
- \(\mathrm{PCT} > 2\mu \mathrm{g / L}\)
A PCT level above 2.0 \( \mu \) g/L on the first day of ICU admission is associated with a high risk for progression to severe sepsis and/or septic shock.
- \(\mathrm{PCT} < 0.5\mu \mathrm{g / L}\)
A PCT level below 0.5 \( \mu \) g/L on the first day of ICU admission is associated with a low
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risk for progression to severe sepsis and/or septic shock.
#### LRTI Antibiotic Decision Making:
- PCT < 0.10 ng/mL
Antibiotic therapy strongly discouraged.
• PCT 0.10-0.25 ng/mL
Antibiotic therapy discouraged.
• PCT 0.26-0.50 ng/mL
Antibiotic therapy encouraged.
• PCT >0.50 ng/mL
Antibiotic therapy strongly encouraged.
#### Sepsis Antibiotic Discontinuation:
- \(\Delta\)PCT \(>80\%\)
Antibiotic therapy may be discontinued
• PCT ≤ 0.50 ng/mL
Antibiotic therapy may be discontinued
#### Recommendations for Laboratory Reports for Initiation and Discontinuation:
The Change in Procalcitonin Calculator is available at http://www.brahms-pct-calculator.com. The Change in Procalcitonin Calculator can be used to determine \( \Delta \) PCT results. It is suggested to report the numerical PCT values (individual or paired). For paired PCT values the report should also indicate if the \( \Delta \) PCT(%) was \( \leq 80\% \) or >80%. The laboratory report should include a reference or a link to the package insert for a guided interpretation of the test results.
#### k. Specimen Stability:
Refer to K160729 for stability data.
#### 1. Sample Matrix Comparison:
See K160729 for study design and data.
SST is an acceptable sample type for use with the Elecsys PCT assay
Li-Heparin plasma is an acceptable sample type for use with the Elecsys BRAHMS PCT assay
K2-EDTA plasma is an acceptable sample type for use with the Elecsys BRAHMS PCT assay.
K3-EDTA plasma is an acceptable sample type for use with the Elecsys BRAHMS PCT assay.
### 2. Clinical Studies:
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The clinical performance of the Elecsys BRAHMS PCT assay was establishing with multicenter testing of retrospective specimens available as frozen samples from adult patients (i.e., >18 years of age) diagnosed with severe sepsis or septic shock who were enrolled in the BRAHMS MOSES study from the Intensive Care Unit, the emergency department, other wards or directly from out of hospital and subsequently admitted to the ICU.
The clinical concordance analysis in this report was performed with all available valid test results obtained in the Elecsys BRAHMS PCT clinical performance study. The line listings of the Elecsys BRAHMS PCT clinical performance study were included in K160729.
The clinical concordance analysis of the Elecsys BRAHMS PCT clinical performance study shows more than 97% total agreement between the Elecsys BRAHMS PCT and the BRAHMS PCT sensitive Kryptor (predicate device) at the medical decision points 0.1, 0.25, 0.5 and 2.0 ng/mL. The regression slopes are within +/- 10% of identity in Passing-Bablok and Weighted Deming Analysis. This demonstrates equivalence to the predicate device.
Table 7: Elecsys BRAHMS PCT vs Predicate at 0.5 ng/mL
| Elecsys BRAHMS PCT on cobas e 411 | BRAHMS PCT sensitive Kryptor | | Total |
| --- | --- | --- | --- |
| | ≤ 0.5 ng/mL | > 0.5 ng/mL | |
| ≤ 0.5 ng/mL | 667 | 50 | 717 |
| > 0.5 ng/mL | 18 | 1882 | 1900 |
| Total | 685 | 1932 | 2617 |
Table 8: Elecsys BRAHMS PCT vs Predicate at 2.0 ng/mL
| Elecsys BRAHMS PCT on cobas e 411 | BRAHMS PCT sensitive Kryptor | | Total |
| --- | --- | --- | --- |
| | ≤ 2.0 ng/mL | > 2.0 ng/mL | |
| ≤ 2.0 ng/mL | 1223 | 56 | 1279 |
| > 2.0 ng/mL | 13 | 1325 | 1338 |
| Total | 1236 | 1381 | 2617 |
Table 9: 3 x 3 Table Elecsys BRAHMS PCT vs Predicate
| Elecsys BRAHMS PCT on cobas e 411 | BRAHMS PCT sensitive Kryptor | | | Total |
| --- | --- | --- | --- | --- |
| | ≤ 0.5 ng/mL | 0.5 ng/mL < PCT ≤ 2.0 ng/mL | > 2.0 ng/mL | |
| ≤ 0.5 ng/mL | 667 | 48 | 2 | 717 |
| 0.5 ng/mL < PCT ≤ 2.0 | 18 | 490 | 54 | 562 |
| > 2.0 ng/mL | 0 | 13 | 1325 | 1338 |
| Total | 685 | 551 | 1381 | 2617 |
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Table 10: 5 x 5 Table Elecsys BRAHMS PCT vs Predicate
| Elecsys BRAHMS PCT on cobas e 411 | BRAHMS PCT sensitive Kryptor | | | | | Total |
| --- | --- | --- | --- | --- | --- | --- |
| | ≤ 0.1 ng/mL | 0.1 ng/mL < PCT≤ 0.25 ng/mL | 0.25 ng/mL < PCT≤ 0.5 ng/mL | 0.5 ng/mL < PCT ≤ 2.0 ng/mL | > 2.0 ng/mL | |
| ≤ 0.1 ng/mL | 97 | 47 | 1 | 1 | 1 | 147 |
| 0.1 ng/mL < PCT≤ 0.25 ng/mL | 6 | 240 | 42 | 1 | 1 | 290 |
| 0.25 ng/mL < PCT≤ 0.5 ng/mL | 0 | 16 | 218 | 46 | 0 | 280 |
| 0.5 ng/mL < PCT≤ 2.0 ng/mL | 1 | 1 | 16 | 490 | 54 | 562 |
| > 2.0 ng/mL | 0 | 0 | 0 | 13 | 1325 | 1338 |
| Total | 104 | 304 | 277 | 551 | 1381 | 2617 |
Table 11: Comparison Elecsys BRAHMS PCT vs Predicate
N = 2617 (104 ≤ 0.1 ng/mL, 408 ≤ 0.25 ng/mL; 685 ≤ 0.5 ng/mL; 1236 ≤ 2.0 ng/mL)
| Cutoff (> vs. ≤) | PositiveAgreement (95% CI) | NegativeAgreement(95% CI) | TotalAgreement | Cohen'sKappa |
| --- | --- | --- | --- | --- |
| 0.10 ng/mL | 93.3% | 98.0% | 97.8% | 0.762 |
| | (86.6 - 97.3) | (97.4 - 97.3) | | |
| 0.25 ng/mL | 95.6% | 97.9% | 97.5% | 0.908 |
| | (93.1 - 97.4) | (97.2 - 98.4) | | |
| 0.50 ng/mL | 97.4% | 97.4% | 97.4% | 0.934 |
| | (95.9 - 98.4) | (96.6 - 98.1) | | |
| 2.00 ng/mL | 98.9% | 95.9% | 97.4% | 0.947 |
| | (98.2 - 99.4) | (94.8 - 96.9) | | |
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Table 12: Weighted Deming and Passing Bablok Regression Analysis
| Parameter | Passing Bablok Regression | Weighted Deming (λ=1) Regression Analysis |
| --- | --- | --- |
| n | 2617 | 2617 |
| Slope | 0.959 | 0.949 |
| 95% CI | [0.947; 0.972] | [0.937; 0.961] |
| Intercept | -0.023 | -0.008 |
| 95% CI | [-0.028; -0.018] | [-0.013; -0.004] |
| Pearson Correlation Coefficient (R) | 0.989 | 0.989 |
| Spearman Correlation Coefficient (R) | 0.990 | 0.990 |
| Sample Range | [0.02; 662.86] | [0.02; 662.86] |
Figure 1: Weighted Deming Regression plots of Elecsys BRAHMS PCT versus Predicate
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Figure 2: Passing Bablok Regression plots of Elecsys BRAHMS PCT versus Predicate
#### 3. Clinical Cut-off:
See assay cut-off M.1.j above.
### N. Instrument Name:
The cobas e411 immunoassay analyzer
### O. System Descriptions:
#### 1. Modes of Operation:
See Device Description (Section I) above
#### 2. Software
FDA has reviewed applicant's Hazard Analysis and software development processes for this line of product types:
Yes ____X____ or No ____
#### 4. Specimen Identification:
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A barcode reader reads the barcodes on each tube for positive identification.
4. Specimen Sampling and Handling:
See Sample Stability (M.1.k) above.
5. Calibration:
Results are determined via a calibration curve which is instrument specifically generated by 2-point calibration and a master curve provided via the reagent barcode.
Calibration must be performed once per reagent lot using fresh reagent (i.e. not more than 24 hours since the reagent kit was registered on the analyzer). Renewed calibration is recommended as follows:
- after 8 weeks when using the same reagent lot
- after 7 days (when using the same reagent kit on the analyzer)
- as required: e.g. quality control findings outside the defined limits
6. Quality Control:
See “Traceability, Stability, Expected Values (controls, calibrators, or methods)” Section (M.1.c) above.
# **P. Other Supportive Instrument Performance Characteristics Data Not Covered In the “Performance Characteristics” Section above:**
N/A
# **Q. Proposed Labeling:**
The labeling supports the finding of substantial equivalence for this device.
# **R. Conclusion:**
The submitted information in this premarket notification is complete and supports a substantial equivalence decision.
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