Search Results

The Nichols Advantage® 25-Hydroxyvitamin D assay is for use only on the Nichols Advantage® Specialty System. The Nichols Advantage 25-Hydroxyvitamin D assay is intended for the quantitative determination of 25-hydroxyvitamin D (25-OH-D) and other hydroxylated metabolites of vitamin D in serum or plasma to be used as an aid in the assessment of vitamin D sufficiency in an adult population. Assay results should be used in conjunction with other clinical data to assist the clinician in making individual patient management decisions.

The Nichols Advantage 25-OH-D (NA 25-OH-D) contains sufficient reagents for 100 tests. The NA 25-OH-D is an automated 25-OH-D assay for use only on the Nichols Advantage Immunoassay System.

This looks like a 510(k) summary for a medical device called the "Nichols Advantage® 25-Hydroxyvitamin D" assay. It's an immunoassay designed to measure 25-hydroxyvitamin D (25-OH-D) levels in serum or plasma.

Here's an analysis of the acceptance criteria and the study that proves the device meets those criteria, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance:

The document doesn't explicitly state "acceptance criteria" for each performance characteristic in a separate, clear table with pass/fail thresholds. Instead, it presents performance characteristics for both the new device and the predicate device, implying that equivalence to the predicate device's performance is the acceptance criterion.

However, based on the Comparison of Performance Characteristics table and the Comparison to Predicate Device section, we can infer some criteria and compare them to the reported performance.

• Passing & Bablok slope close to 1
• Passing & Bablok intercept close to 0
• Pearson correlation (r) value indicating strong correlation
• High overall agreement using a 20 ng/mL cutoff. | Y=1.1(X) - 0.6 (95% cf slope: 0.94 to 1.27; 95% cf intercept: -4.6 to 2.1)
  Pearson correlation r=0.84 (95%cf: 0.76-0.89)
  Relative agreement at 20 ng/mL or less: 97.8%
  Relative agreement at 20 ng/mL and higher: 90.6%
  Overall agreement (20 ng/mL cutoff): 93.9% |
  | Analytical Sensitivity | ≤ 1.5 ng/mL (Predicate) | 4 ng/mL |
  | Functional Sensitivity | 2.5 ng/mL (Predicate) | 7 ng/mL |
  | Within-Run Precision (%CV) | 8.6-12.5% (Predicate) | 3.0-4.5% (Overall study: Ave. CV 4.7%, Median CV 3.3%) |
  | Total Precision (%CV) | 8.2-11.0% (Predicate) | 6.4-14.5% |
  | Recovery | 92-119% (Predicate) | 90-99% |
  | Linearity | 96-110% (Predicate) | 80-109% |
  | Specificity (Cross-reactivity) | Detailed comparative percentages for various Vitamin D derivatives (e.g., Vitamin D2, D3, 25-OH-D2, 25-OH-D3, 24,25(OH)2D3, 25-26-OH2D3, 1,25(OH)2D3) with the predicate. | Closely comparable percentages for various Vitamin D derivatives, e.g., 25-OH-D2 and 25-OH-D3 both 100% for both devices; some differences in minor metabolites are noted and discussed as technology differences. |
  | Reportable Range | 5.0-100 ng/mL (Predicate) | 7-120 ng/mL |

Analysis of Performance vs. Criteria:

• Method Comparison: The Passing & Bablok results (Y=1.1(X) - 0.6, slope 0.94 to 1.27, intercept -4.6 to 2.1) and Pearson correlation (r=0.84) demonstrate a good correlation and substantial equivalence, despite some noted bias for higher values. The high overall agreement (93.9%) at the 20 ng/mL cutoff further supports this.
• Precision: The Nichols Advantage device shows better within-run precision (3.0-4.5% vs. 8.6-12.5% for predicate) and comparable total precision.
• Sensitivity: The analytical and functional sensitivities for the Nichols Advantage (4 ng/mL and 7 ng/mL) are higher (less sensitive) than the predicate (≤ 1.5 ng/mL and 2.5 ng/mL). The reportable range for the new device also starts higher (7 ng/mL vs. 5.0 ng/mL). This is a point of difference but not explicitly stated as failing an acceptance criterion, especially if the device is intended for "assessment of vitamin D sufficiency" where clinical cutoffs are typically higher (e.g., 20 ng/mL). The device still covers the critical 20 ng/mL cutoff for sufficiency.
• Recovery and Linearity: Both are within generally acceptable ranges and comparable to the predicate.
• Specificity: While there are minor differences in cross-reactivity percentages for some metabolites (e.g., 25-26-OH2D3 and 1,25(OH)2D3), these are acknowledged as relating to "differences in immunoassay technology" and not affecting the intended use.

Study Proving Acceptance:

The primary study proving the device meets the acceptance criteria is a method comparison study against the legally marketed predicate device, the DiaSorin 25-Hydroxyvitamin D 125I RIA kit.

2. Sample size used for the test set and the data provenance:

• Test Set Sample Size:
  • Method Comparison: 111 total samples were initially assayed (each in duplicate).
    • 80 samples were identified as being within the reportable ranges of both methods and had acceptable precision. These 80 samples were used for the statistical analysis (Deming, Passing & Bablok, Pearson).
    • 19 samples were below the reportable range of the subject device.
    • 12 samples were deleted due to unacceptable imprecision (>4 standard deviations), primarily associated with the DiaSorin assay.
    • Thus, the core statistical comparison was based on 80 samples. The concordance chart combined the 80 precise samples and the 19 below-range samples, making the concordance analysis based on 99 samples.
  • Clinical Study (separate): 100 patients with a diagnosis of chronic renal insufficiency.
• Data Provenance: The document does not specify the country of origin for the samples. It mentions "samples were assayed over 3 days in 3 different runs," indicating the data was generated specifically for this comparison study, making it prospective data collection for the method comparison. The clinical study on renal patients is also likely prospective or involved newly collected samples for evaluation.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

• For the method comparison study, the "ground truth" is established by the predicate device (DiaSorin 25-Hydroxyvitamin D 125I RIA kit). There were no human experts establishing ground truth; it's a comparison of two analytical methods.
• For the clinical study, the "ground truth" for vitamin D deficiency/insufficiency was assessed using the device's results in conjunction with "biochemical measures of disordered calcium mineral ion metabolism." It does not explicitly state that experts established ground truth for each case. The study aimed to show the device's consistency with known clinical relationships (e.g., renal failure and low 25-OH-D).

4. Adjudication method (e.g., 2+1, 3+1, none) for the test set:

• None. For the method comparison, the reference is the predicate device's measurement. Discordant results are analyzed statistically, not adjudicated by experts.

5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:

• No. This document describes an in vitro diagnostic (IVD) assay, not an AI-powered diagnostic imaging or interpretation device that would involve human readers. Therefore, an MRMC study and analysis of human reader improvement with AI assistance are not applicable.

6. If a standalone (i.e. algorithm only without human-in-the loop performance) was done:

• Yes. The device is an automated immunoassay system. Its performance is measured as a standalone analytical instrument. There is no human-in-the-loop performance component in the direct interpretation of the assay result, although clinicians use the result in conjunction with other data for patient management.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):

• Method Comparison: The ground truth is the results from the predicate device (DiaSorin 25-Hydroxyvitamin D 125I RIA kit). This is a comparison against a previously validated and legally marketed analytical method.
• Clinical Study: The ground truth for correlating 25-OH-D levels with clinical status was based on a diagnosis of chronic renal insufficiency and "biochemical measures of disordered calcium mineral ion metabolism." This leans towards clinical outcomes/correlation data rather than a single definitive ground truth like pathology for each case.

8. The sample size for the training set:

• The document does not explicitly describe a training set. This is common for traditional immunoassay development, where a "training set" in the machine learning sense isn't typically used. Instead, development involves optimizing reagents, calibration, and assay parameters, often through iterative testing with various samples, but not usually in a formally defined "training set" that precedes a distinct "test set" in the way an AI algorithm might require. The samples mentioned (111 for method comparison, 100 for clinical study) are for validation, not distinct training.

9. How the ground truth for the training set was established:

• As a formal "training set" is not explicitly defined or discussed in the context of this traditional immunoassay, the concept of establishing ground truth for it is not applicable here. The overall "truth" for this device's validation is based on its analytical accuracy and its agreement with a predicate device, which itself was previously validated.

Ask a specific question about this device