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CRYOcheck Hex LA is for clinical laboratory use as a qualitative test kit intended to aid in the detection of lupus anticoagulants (LA) in 3.2% citrated human plasma by the application of hexagonal phase phospholipids. CRYOcheck Hex LA should be used as an integrated test for lupus anticoagulant detection. For in vitro diagnostic use. The performance of this device has not been established in neonate and pediatric patient populations.

CRYOcheck Hex LA is comprised of three reagents supplied in a frozen format as follows:

LA Start: Pooled normal plasma with buffer and a heparin neutralizer.

LA Correct: Pooled normal plasma with buffer, a heparin neutralizer, and inverted hexagonal phase phospholipid.

LA APTT: Silica-based lupus sensitive APTT reagent with stabilizer.

1. Acceptance Criteria and Device Performance:

2. Sample Sizes and Data Provenance:

• Precision Study:
  • 3 control plasmas and 5 plasmas with varying LA positivity.
  • Tested in duplicate, twice a day for 20 days per lot of reagent (3 lots used).
• Reproducibility Study:
  • 3 control plasmas and 5 plasmas with varying LA positivity.
  • Each sample tested in triplicate, twice a day for 5 days for each of the 3 lots of reagent.
• Normal Range and Assay Cut-off Study:
  • Normal samples: 137 on Analyzer A, 126 on Analyzer B.
  • Each sample tested using 3 lots of CRYOcheck Hex LA.
• Shelf Life Stability Study:
  • 3 lots of CRYOcheck Hex LA.
  • 10 replicates of 3 controls tested at time = 0 and regular intervals up to 37 months.
  • One additional plasma sample close to the cut-off for one lot.
• In-Use Stability Study:
  • 3 lots of CRYOcheck Hex LA.
  • 5 replicates of 3 control plasmas and 4 test plasmas with varying levels of LA.
  • Tested at 0, 2, 4, 6, 7, 8, and 9 hours.
• Interference Studies:
  • Patient plasma samples spiked with possible interferents.
  • 20 replicates of spiked samples tested alongside 20 replicates of corresponding blank matrix control.
  • Single lot of CRYOcheck Hex LA used.
• Method Comparison Studies (Test Set):
  • Total samples: 446
    • 124 known (previously characterized) LA positive samples.
    • 75 normal (presumed LA negative) samples from individuals with other medical conditions including autoimmune disorders.
    • 220 LA target screening population samples.
  • Data Provenance: The document does not explicitly state the country of origin for the patient samples. The study involved one internal site and three external sites, suggesting a multi-center study. It is a retrospective study since samples were "known (previously characterized) LA positive" or "presumed LA negative."
• Sample Integrity Study:
  • 64 samples.

3. Number of Experts and Qualifications for Ground Truth:

• This device is an in vitro diagnostic (IVD) test, not an AI/imaging device requiring expert interpretation for ground truth.
• The ground truth for the method comparison study was established by comparing the CRYOcheck Hex LA results against a legally marketed predicate device, Staclot® LA (K923731).
• The determination of "known (previously characterized)" LA positive samples and "presumed LA negative" samples would implicitly rely on established clinical or laboratory diagnostic procedures, which are performed by qualified laboratory personnel, not typically "experts" in the sense of a radiology reader study.

4. Adjudication Method for the Test Set:

• Not applicable as this is a comparison study against a predicate device's results, not a human reader study needing adjudication. The "ground truth" for the test set was the result obtained from the predicate device (Staclot® LA).

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:

• No, an MRMC comparative effectiveness study was not done. This is an IVD device measuring a biomarker, not an imaging AI device assisting human readers. Therefore, the concept of "effect size" of how human readers improve with AI vs. without AI assistance is not relevant here.

6. Standalone Performance:

• Yes, the performance data presented (Precision, Reproducibility, Normal Range, Stability, Interferences) are essentially standalone (algorithm-only) performance characteristics of the CRYOcheck Hex LA device in a laboratory setting.
• The method comparison study also evaluated the device's performance independently against a predicate, effectively demonstrating its standalone performance in identifying LA status.

7. Type of Ground Truth Used:

• For the method comparison study (test set), the ground truth was comparison to a legally marketed predicate device (Staclot® LA).
• For the known LA positive/negative samples, the ground truth was "previously characterized" LA status, likely established through a combination of clinical diagnosis and existing laboratory methods.

8. Sample Size for the Training Set:

• This document describes a 510(k) submission for an in vitro diagnostic (IVD) device, not an AI/machine learning device that typically involves a "training set" in the same computational sense.
• The development and optimization of such an IVD assay would involve internal development samples and studies, but these are not referred to as "training sets" in the context of this regulatory filing. The provided information focuses on analytical and clinical performance validation.

9. How the Ground Truth for the Training Set Was Established:

• Not applicable due to the nature of the device as explained in point 8. The device's "training" or development would involve laboratory optimization and calibration using reference materials and characterized samples, but not "ground truth" in the AI sense for a dedicated "training set."

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