(256 days)
No
The device description and performance studies focus on standard in vitro diagnostic assay components and analytical methods, with no mention of AI or ML.
No
Explanation: The device is an in vitro diagnostic device used for quantitative determination of cortisol to assist in the diagnosis and treatment of disorders, not to provide therapy itself.
Yes
The "Intended Use / Indications for Use" section explicitly states that the device is "an in vitro diagnostic device" and that its results are used "to assist clinicians in the diagnosis and treatment of disorders of the adrenal gland."
No
The device description explicitly states it consists of a "reagent cartridge" containing multiple chemical reagents, which are physical components, not software.
Yes, this device is an IVD (In Vitro Diagnostic).
Here's why:
- Intended Use Statement: The very first sentence explicitly states: "The IDS Cortisol assay is an in vitro diagnostic device intended for the quantitative determination of cortisol in human serum and plasma..."
- Device Description: The description details the reagents used to perform the test on biological samples (serum and plasma), which is characteristic of an in vitro diagnostic.
- Intended User / Care Setting: It states "For in vitro diagnostic use only."
- Performance Studies: The performance studies described (precision, linearity, detection limit, analytical specificity, method comparison, matrix comparison, expected values) are all standard evaluations for an in vitro diagnostic assay.
- Predicate Device: The mention of a predicate device (Roche Elecsys Cortisol II) with a K number (K152227) indicates that this device is being compared to a previously cleared IVD.
All of these points strongly confirm that the IDS Cortisol assay is an in vitro diagnostic device.
N/A
Intended Use / Indications for Use
The IDS Cortisol assay is an in vitro diagnostic device intended for the quantitative determination of cortisol in human serum and plasma on the IDS system. Results are to be used in conjunction with other clinical and laboratory data to assist clinicians in the diagnosis and treatment of disorders of the adrenal gland.
Product codes (comma separated list FDA assigned to the subject device)
CGR
Device Description
The IDS Cortisol assay consists of a reagent cartridge. The reagent cartridge contains multiple reagents:
- -MPE1:Magnetic particles coated rat anti-mouse monoclonal antibody in a phosphate buffer with Proclin as preservative.
- CONJ: Cortisol coupled with an acridinium ester derivative in = phosphate buffer with Proclin as a preservative.
- mAb: Mouse anti-cortisol monoclonal antibody in phosphate buffer with Proclin as a preservative .;
- BUF: HEPES buffer containing Proclin as preservative . -
Mentions image processing
Not Found
Mentions AI, DNN, or ML
Not Found
Input Imaging Modality
Not Found
Anatomical Site
Not Found
Indicated Patient Age Range
The study cohort included subjects from 21 to 65 years of age.
Intended User / Care Setting
Not Found
Description of the training set, sample size, data source, and annotation protocol
Not Found
Description of the test set, sample size, data source, and annotation protocol
Not Found
Summary of Performance Studies (study type, sample size, AUC, MRMC, standalone performance, key results)
Precision/Reproducibility:
Study type: Precision was evaluated in accordance with a modified protocol based on CLSI EP-5A3, "Evaluation of Precision Performance of Quantitative Measurement Methods".
Sample size: 6 samples were assayed using 3 lots of reagents in duplicate, twice a day for 20 days on 3 systems. The IDS Cortisol assay precision was established using samples with concentrations ranging from approximately 0.80 ug/dL to 46.00 ug/dL. Total N=240 per sample for combined results.
Key results:
Results from 1 representative lot on 1 system:
| Sample | N | Mean Conc. (µg/dL) | Repeatability SD | Repeatability CV | Within system SD | Within system CV |
|---|---|---|---|---|---|---|
| 1 | 80 | 0.94 | 0.07 | 7.8% | 0.15 | 16.2% |
| 2 | 80 | 1.84 | 0.08 | 4.6% | 0.20 | 10.9% |
| 3 | 80 | 5.75 | 0.14 | 2.4% | 0.30 | 5.2% |
| 4 | 80 | 13.06 | 0.31 | 2.4% | 0.52 | 3.9% |
| 5 | 80 | 19.94 | 0.36 | 1.8% | 1.02 | 5.1% |
| 6 | 80 | 44.63 | 0.85 | 1.9% | 1.89 | 4.2% |
| Results for the combined 3 lots on 3 systems: | ||||||
| Sample | N | Mean Conc. (µg/dL) | Within run SD | Within run CV | Total SD | Total CV |
| --- | --- | --- | --- | --- | --- | --- |
| 1 | 240 | 0.88 | 0.06 | 7.1% | 0.14 | 15.3% |
| 2 | 240 | 1.78 | 0.08 | 4.3% | 0.18 | 10.1% |
| 3 | 240 | 5.75 | 0.13 | 2.3% | 0.26 | 4.5% |
| 4 | 240 | 13.09 | 0.25 | 1.9% | 0.43 | 3.3% |
| 5 | 240 | 20.22 | 0.35 | 1.7% | 0.96 | 4.8% |
| 6 | 240 | 44.48 | 0.74 | 1.7% | 2.22 | 5.0% |
Linearity/assay reportable range:
Study type: A linearity study was conducted based on guidance from the CLSI EP6-A.
Sample size: A high human serum sample and a low human serum sample were prepared respectively by spiking a serum sample with Cortisol high concentration solution and diluting a serum sample with Cortisol zero matrix. High and a low serum samples were analysed in addition to 12 evenly spaced dilutions.
Key results: Observed = 1.01 x (Expected) + 0.01 µg/dL; Regression coefficient R2: 1.00. The IDS Cortisol assay is linear over the measuring range 0.59 to 45.00 µg/dL.
Detection limit:
Study type: Determined with guidance from CLSI EP17A2, "Protocols for Determination of Limits of Detection and Limits of Quantitation"
Sample size: 60 blank replicates and 13 low level samples.
Key results: Limit of Blank (LoB) = 0.10 µg/dL, Limit of Detection (LoD) = 0.24 µg/dL, Limit of Quantitation (LoQ) = 0.59 µg/dL.
Analytical specificity (Interference and cross-reactivity):
Study type: Performed in accordance with the CLSI EP07-A3 Interference.
Key results:
Non-significant interference (
§ 862.1205 Cortisol (hydrocortisone and hydroxycorticosterone) test system.
(a)
Identification. A cortisol (hydrocortisone and hydroxycorticosterone) test system is a device intended to measure the cortisol hormones secreted by the adrenal gland in plasma and urine. Measurements of cortisol are used in the diagnosis and treatment of disorders of the adrenal gland.(b)
Classification. Class II.
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Image /page/0/Picture/0 description: The image contains the logo of the U.S. Food and Drug Administration (FDA). On the left is the Department of Health & Human Services USA logo. To the right of that is the FDA logo, which is a blue square with the letters "FDA" in white. To the right of the blue square is the text "U.S. FOOD & DRUG ADMINISTRATION" in blue.
April 13, 2021
Immunodiagnostic Systems Ltd. Mick Henderson Regulatory Affairs Manager 10 Didcot Way Boldon Business Park Boldon, Tyne and Wear NE35 9PD United Kingdom
Re: K202136
Trade/Device Name: IDS Cortisol Regulation Number: 21 CFR 862.1205 Regulation Name: Cortisol (Hydrocortisone And Hydroxycorticosterone) Test System Regulatory Class: Class II Product Code: CGR Dated: October 8, 2020 Received: October 13, 2020
Dear Mick Henderson:
We have reviewed vour Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food. Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrl/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal
1
statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801 and Part 809); medical device reporting of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.
For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE(@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
Sincerely.
Kellie B. Kelm -S
Kellie B. Kelm Director Division of Chemistry and Toxicology Devices OHT7: Office of In Vitro Diagnostics and Radiological Health Office of Product Evaluation and Quality Center for Devices and Radiological Health
Enclosure
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Indications for Use
510(k) Number (if known) K202136
Device Name IDS Cortisol
Indications for Use (Describe)
The IDS Cortisol assay is an in vitro diagnostic device intended for the quantitative determination of cortisol in human serum and plasma on the IDS system. Results are to be used in conjunction with other clinical and laboratory data to assist clinicians in the diagnosis and treatment of disorders of the adrenal gland.
Type of Use (Select one or both, as applicable)
| ☑ Prescription Use (Part 21 CFR 801 Subpart D) | ☐ Over-The-Counter Use (21 CFR 801 Subpart C) |
|---|---|
| ------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------- |
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Image /page/3/Picture/0 description: The image contains the logo for Immunodiagnostic Systems (IDS). The logo features the letters 'ids' in a stylized, lowercase font, with a red circle above the 'i'. Below the letters, the words 'immunodiagnosticsystems' are written in a smaller, red font. The logo is simple and modern, with a focus on the company's name and its area of expertise.
510(k) SUMMARY
| 510k Number | K202136 | |
|---|---|---|
| Introduction | According to the requirements of 21CFR807.92, the following | |
| information provides sufficient detail to understand the basis for a | ||
| determination of substantial equivalence. | ||
| Submitter | Immunodiagnostic Systems Limited | |
| 10 Didcot Way | ||
| Boldon Business Park | ||
| Boldon | ||
| Tyne and Wear | ||
| NE35 9PD | ||
| United Kingdom | ||
| Contact Person: Mick Henderson | ||
| Phone: +44 191 5190660 | ||
| Fax: +44 191 5190760 | ||
| Email: mick.henderson@idsplc.com | ||
| Secondary Contact: Lee Harris | ||
| Phone: +44 191 5190660 | ||
| Fax: +44 191 5190760 | ||
| Email : lee.harris@idsplc.com | ||
| Date prepared: 27 July 2020 | ||
| Device Name | Proprietary names: | IDS Cortisol |
| Common names: | As above | |
| Classification: | 21CFR862.1205 Cortisol (hydrocortisone | |
| and hydroxycorticosterone) test system. | ||
| Class II | ||
| Product Code: | CGR |
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Image /page/4/Picture/0 description: The image shows the logo for Immunodiagnostic Systems (IDS). The logo features the letters "ids" in a stylized, interconnected design, with a red dot above the "i". Below the letters, the words "immunodiagnostic systems" are written in a smaller font size. The color scheme is primarily gray and red.
Predicate Device The IDS Cortisol is substantially equivalent to other products in commercial distribution intended for similar use. We claim equivalency to the currently marketed Roche Elecsys Cortisol II (K152227).
The IDS Cortisol assay consists of a reagent cartridge. The reagent Device Description cartridge contains multiple reagents:
- -MPE1:Magnetic particles coated rat anti-mouse monoclonal antibody in a phosphate buffer with Proclin as preservative.
- CONJ: Cortisol coupled with an acridinium ester derivative in = phosphate buffer with Proclin as a preservative.
- mAb: Mouse anti-cortisol monoclonal antibody in phosphate buffer with Proclin as a preservative .;
- BUF: HEPES buffer containing Proclin as preservative . -
Indications for Use
The IDS Cortisol assay is an in vitro diagnostic device intended for the quantitative determination of cortisol in human serum and plasma on the IDS system. Results are to be used in conjunction with other clinical and laboratory data to assist clinicians in the diagnosis and treatment of disorders of the adrenal gland.
- Conditions for use: For in vitro diagnostic use only. Rx Only
Special instrument Requirements:
IDS-iSYS Multi-Discipline Automated System (K091849)
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Image /page/5/Picture/0 description: The image shows the logo for Immunodiagnostic Systems (IDS). The logo features the letters "ids" in a stylized, connected font, with a red circle above the "i". Below the letters, the words "immunodiagnosticsystems" are written in a smaller, red font. The logo is simple and modern, with a focus on the company's name and area of expertise.
Comparison Tables
Similarities compared to the chosen (FDA cleared; marketed) predicate device (K152227)
| Assay
Performance | Predicate Device
Roche Elecsys Cortisol II
(K152227) | Candidate Device
IDS Cortisol |
|----------------------------------------------|------------------------------------------------------------|----------------------------------|
| Intended Use | For quantitative determination
of Cortisol | same |
| Method of
detection (Test
methodology) | chemiluminescence | same |
Differences compared to the chosen (FDA cleared; marketed) predicate device (K152227)
| Predicate Device | Candidate Device | |
|---|---|---|
| Performance | Roche Elecsys Cortisol II | IDS Cortisol |
| (K152227) | ||
| Indications for | ||
| Use | Immunoassay for the in vitro | |
| quantitative determination of | ||
| cortisol in human serum, | ||
| plasma, urine and saliva. The | ||
| determination of cortisol is | ||
| used for the recognition and | ||
| treatment of functional | ||
| disorders of the adrenal gland. | ||
| The electrochemiluminescence | ||
| immunoassay "ECLIA" is | ||
| intended for use on Elecsys | ||
| and cobas e immunoassay | The IDS Cortisol assay is an in | |
| vitro diagnostic device intended for | ||
| the quantitative determination of | ||
| cortisol in human serum and | ||
| plasma on the IDS system. Results | ||
| are to be used in conjunction with | ||
| other clinical and laboratory data | ||
| to assist clinicians in the diagnosis | ||
| and treatment of disorders of the | ||
| adrenal gland. | ||
| Sample Type | Human Serum, plasma, urine | |
| and saliva | Human Serum and plasma | |
| Sample | ||
| Volume | 10 µL | 30 µL |
| Range of assay | 3 - 1750 nmol/L | |
| (0.109 to 63.4 ug/dL) | 0.59 - 45 µg/dL | |
| Sensitivity | LoB 1.0 nmol/L (0.036 µg/dL) | |
| LoD 1.5 nmol/L (0.054 µg/dL) | ||
| LoQ 3.0 nmol/L (0.109 µg/dL) | ||
| Morning hours 6-10am | ||
| 95th percentile 6.02-18.4 µg/dL | ||
| Afternoon hours 4-8pm | ||
| 95th percentile 2.68-10.5 µgd/L | LoB 0.1 µg/dL | |
| LoD 0.24 µg/dL | ||
| LoQ 0.59 µg/dL | ||
| Morning hours 6-10am | ||
| 95th percentile 4.23-20.1 µg/dL | ||
| Afternoon hours 4-8pm | ||
| 95th percentile 2.37-13.6 µg/dL | ||
| Precision | Repeatability n =84 | |
| 1.4% to 7.1% in the | ||
| concentration range 0.112 to | ||
| 57.7 µg/dL | ||
| Intermediate Precision n = 84 | ||
| 2.5% to 12.7% in the | ||
| concentration range 0.014 to | ||
| 0.653 µg/dL | Within Run / Repeatability | |
| Precision n =80 | ||
| 1.8% to 7.8% in the concentration | ||
| range 0.94 to 44.63 µg/dL | ||
| Within System n = 80 | ||
| 3.9% to 16.2% in the concentration | ||
| range 0.94 to 44.63 μg/L | ||
| Specificity, | ||
| Interfering | ||
| substances | ||
| And | ||
| Cross | ||
| Reactivity | Interfering Substances | |
| Bilirubin 25 mg/dL | ||
| Biotin 30ng/mL | ||
| Haemoglobin No Claim | ||
| Human Anti | ||
| Mouse Antibody | ||
| (HAMA) No Claim | ||
| Rheumatoid Factor 600IU/mL | ||
| Total Protein No Claim | ||
| Triglycerides No Claim | ||
| Acetaminophen No Claim | Interfering Substances | |
| Bilirubin – | ||
| conjugated 40 mg/dL | ||
| Bilirubin – | ||
| unconjugated 40 mg/dL | ||
| Biotin 6 µg/dL | ||
| Haemoglobin 500 mg/dL | ||
| Human Anti | ||
| Mouse Antibody | ||
| (HAMA) 1000 ng/dL | ||
| Rheumatoid Factor 2000IU/mL | ||
| Total Protein 12 g/dL | ||
| Triglycerides 3000mg/dL | ||
| Acetaminophen 200 µg/ml |
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Image /page/6/Picture/0 description: The image shows the logo for Immunodiagnostic Systems (IDS). The logo features the letters "ids" in a stylized, sans-serif font, with a red circle above the "i". Below the letters, the words "Immunodiagnostic systems" are written in a smaller, red font.
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Image /page/7/Picture/0 description: The image shows the logo for Immuno Diagnostic Systems (IDS). The logo features the letters 'ids' in a stylized, sans-serif font, with the 'i' having a red circular dot above it. Below the letters, the words 'immunodiagnosticsystems' are written in a smaller, sans-serif font. A registered trademark symbol is located to the upper right of the 's' in 'ids'.
Cross Reactivity 11-Deoxycorticosterone 10ug/L yields a result of 0.64% 11-Deoxycortisol 10ug/L yields a result of 4.9% 17-a-Hydroxyprogesterone 10ug/L vields a result of 0.08% Corticosterone 10ug/L vields a result of 2.48% Cortisone 10ug/L yields a result of 6.58% Dexamethasone 10ug/L yields a result of not detectable Prednisone 10ug/L yields a result of 2.23% Progesterone 10ug/L yields a result of 0.035% 21-Deoxycortisol 1 ug/L yields a result of 2.4% Prednisolone 0.1ug/L yields a result of 7.98% 6-a-Methylprednisolone
0.1µg/L yields a result of 12.0%
Cross Reactivity 11-Deoxycorticosterone 1000ug/dL yields a result of 2.2%
11-Deoxycortisol 100ug/dL yields a result of 11.5%
17-a-Hydroxyprogesterone 1000ug/dL yields a result of 2.6%
Corticosterone 100ug/dL vields a result of 19.9%
Cortisone 100ug/dL yields a result of 36.5%
Dexamethasone 1000ug/dL yields a result of 1.4%
Prednisone 100ug/dL yields a result of 43.5%
Progesterone 1000ug/dL yields a result of 0.3%
21-Deoxycortisol 100ug/dL vields a result of 37%
Prednisolone 50ug/dL yields a result of 51.3%
6-a-Methylprednisolone 10ug/dL yields a result of 0%
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Image /page/8/Picture/0 description: The image shows the logo for Immunodiagnostic Systems (IDS). The logo features the letters "ids" in a stylized, sans-serif font, with the "i" having a red circular dot above it. Below the letters, the words "Immunodiagnostic Systems" are written in a smaller, red font.
| Method
comparison | Against Elecsys Cortisol
(K070788):
n = 536 | Against Elecsys Cortisol II
(K152227):
n = 194 |
|----------------------|--------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------|
| | Elecsys Cortisol II =
$0.76 x (Elecsys Cortisol) -1.85$
µg/L | IDS Cortisol =
$1.06 x (Roche Elecsys Cortisol II) - 0.10$ µg/dL |
| | Correlation coefficient (r) =
0.968 | Correlation coefficient (r) = 0.99 |
| Linearity | 3.0 to 1750 nmol/L | 0.59 – 45 µg/dL
Observed =
$1.01 x (Expected) +0.01$ µg/dL
Regression coefficient R2: 1.00 |
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Image /page/9/Picture/0 description: The image shows the logo for Immunodiagnostic Systems (IDS). The logo features the letters "ids" in a stylized, gray font, with a red dot above the "i". Below the letters, the words "immunodiagnosticsystems" are written in a smaller, red font. A circled "R" trademark symbol is located in the upper right corner of the logo.
Performance Characteristics (if/when applicable):
-
- Analytical performance:
- a. Precision/Reproducibility:
Precision was evaluated in accordance with a modified protocol based on CLSI EP-5A3, "Evaluation of Precision Performance of Quantitative Measurement Methods". A total of 6 samples were assayed using 3 lots of reagents in duplicate, twice a day for 20 days on 3 systems. The IDS Cortisol assay precision was established using samples with concentrations ranging from approximately 0.80 ug/dL to 46.00 ug/dL.
| Sample | N | Mean Conc.
(µg/dL) | Repeatability | | Within system | |
|--------|----|-----------------------|---------------|------|---------------|-------|
| | | | SD | CV | SD | CV |
| 1 | 80 | 0.94 | 0.07 | 7.8% | 0.15 | 16.2% |
| 2 | 80 | 1.84 | 0.08 | 4.6% | 0.20 | 10.9% |
| 3 | 80 | 5.75 | 0.14 | 2.4% | 0.30 | 5.2% |
| 4 | 80 | 13.06 | 0.31 | 2.4% | 0.52 | 3.9% |
| 5 | 80 | 19.94 | 0.36 | 1.8% | 1.02 | 5.1% |
| 6 | 80 | 44.63 | 0.85 | 1.9% | 1.89 | 4.2% |
Results from 1 representative lot on 1 system:
Results for the combined 3 lots on 3 systems:
| Sample | N | Mean Conc.
(µg/dL) | Within run | | Total | |
|--------|-----|-----------------------|------------|------|-------|-------|
| 1 | 240 | 0.88 | 0.06 | 7.1% | 0.14 | 15.3% |
| 2 | 240 | 1.78 | 0.08 | 4.3% | 0.18 | 10.1% |
| 3 | 240 | 5.75 | 0.13 | 2.3% | 0.26 | 4.5% |
| 4 | 240 | 13.09 | 0.25 | 1.9% | 0.43 | 3.3% |
| 5 | 240 | 20.22 | 0.35 | 1.7% | 0.96 | 4.8% |
| 6 | 240 | 44.48 | 0.74 | 1.7% | 2.22 | 5.0% |
b. Linearity/assay reportable range:
A linearity study was conducted based on guidance from the CLSI EP6-A. A high human serum sample and a low human serum sample were prepared respectively by spiking a serum sample with Cortisol high concentration solution and diluting a serum sample with Cortisol zero matrix. High and a low serum samples were analysed in addition to 12 evenly spaced dilutions which were created by mixing the high and low sample as indicated below:
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Image /page/10/Picture/0 description: The image shows the logo for Immunodiagnostic Systems (IDS). The logo features the letters "ids" in a stylized, interconnected design, with the "i" having a red circular dot above it. Below the main logo, the words "immunodiagnosticsystems" are written in a smaller font, with the "immuno" part in red and the rest in gray.
| Sample | Dilution | Dilution Factor (%) |
|---|---|---|
| 1: | Low (L) | 0 |
| 2: | 0.98L + 0.02H | 2 |
| 3: | 0.95L + 0.05H | 5 |
| 4: | 0.92L + 0.08H | 8 |
| 5: | 0.90L + 0.10H | 10 |
| 6: | 0.80L + 0.20H | 20 |
| 7: | 0.70L + 0.30H | 30 |
| 8: | 0.60L + 0.40H | 40 |
| 9: | 0.50L + 0.50H | 50 |
| 10: | 0.40L + 0.60H | 60 |
| 11: | 0.30L + 0.70H | 70 |
| 12: | 0.20L + 0.80H | 80 |
| 13: | 0.10L + 0.90H | 90 |
| 14: | High (H) | 100 |
Results:
Linearity was evaluated based on CLSI EP-6A, "Evaluation of the Linearity of Quantitative Measurement Procedures". Samples were prepared by diluting a high patient sample with a low patient sample prior to assay. The linear regression of the observed concentrations versus the expected concentrations is:
Observed = 1.01 x (Expected) + 0.01 µg/dL; Regression coefficient R2: 1.00
The IDS Cortisol assay is linear over the measuring range 0.59 to 45.00 µg/dL
c. Traceability, Stability, Expected values (controls, calibrators, or methods):
Traceability
The IDS Cortisol assay is traceable to the LC-MS/MS Candidate Reference Measurement Procedure (cRMP) Total Serum Cortisol. Through analysis of a Joint Committee for Traceability in Laboratory Medicine (JCTLM)-listed panel of higher-order Candidate Reference Materials (CRM), the IDS Cortisol provided metrologically traceable results.
Stability
The stability based on accelerated stability studies determined a shelf life of 12 months
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Image /page/11/Picture/0 description: The image shows the logo for Immuno Diagnostic Systems (IDS). The logo features the letters "ids" in a stylized, sans-serif font, with a red circle above the "i". Below the letters, the words "immunodiagnosticsystems" are written in a smaller, red font. The logo is simple and modern, with a focus on the company's name and area of expertise.
d. Detection limit:
The limit of blank (LoB), limit of detection (LoD) and limit of quantitation (LoQ) were determined with guidance from CLSI EP17A2, "Protocols for Determination of Limits of Detection and Limits of Quantitation" using 60 blank replicates and 13 low level samples.
| Sensitivity | Concentration (µg/dL) |
|---|---|
| Limit of Blank (LoB) | 0.10 |
| Limit of Detection (LoD) | 0.24 |
| Limit of Quantitation (LoQ) | 0.59 |
e. Analytical specificity:
Interference and cross-reactivity studies were performed in accordance with the CLSI EP07-A3 Interference.
The potential interference of each substance in the specific detection of Cortisol, with the exception of Rheumatoid Factor (see the description of the Rheumatoid Factor interference), was tested using human serum samples with low and high cortisol concentrations. Interference substances were spiked into the serum samples and the results were measured and compared between the spiked and unspiked samples.
% Interference was calculated using the following formula:
$$% \text{Interference} = \underbrace{(\text{mean spilled concentration} - \text{mean unspilled concentration})}_{\text{mean unspilled concentration}} \ge 100$$
To determine potential interference of Rheumatoid Factor, a serum sample with low Cortisol and high Rheumatoid Factor concentration was diluted 1:2 and 1:4 in cortisol zero matrix and each dilution was assayed in duplicate. Linearity on dilution was assessed.
% Observed/Expected (%O/E) was calculated using the following formula:
% O/E= observed mean concentration x 100 expected concentration
12
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The following compounds were tested and found not to interfere significantly with the test, based on the predefined acceptance criteria of non-significant interference of