Studybox Research CLIA Waiver Studies

Point-of-Care PT/INR Test

Accuracy in the hands of untrained intended-use operators at waived sites.

Studybox

CLIA Waiver Studies

Point-of-care INR monitoring of warfarin therapy spans clinic testing and patient self-testing at home, and both have waived or home-use precedents. The clinical study is a method comparison against a laboratory PT/INR using a reference thromboplastin, with agreement assessed not just as a regression but in the clinical categories that drive dosing. The known limitation of point-of-care INR is reduced agreement at high INR values, and the study must enroll enough patients above the therapeutic range to characterize it.

Enrollment comes from anticoagulation clinics, where patients on warfarin are seen regularly and INR values span the range, including supratherapeutic values on the day of a dose adjustment. Patients with antiphospholipid antibodies, those transitioning from heparin and those with hematocrit outside the device's range are typical exclusions or separately analyzed groups, because these conditions affect point-of-care PT methods differently from laboratory methods.

Analyte: Prothrombin time, reported as International Normalized Ratio (INR)
Therapeutic area: Hematology
Specimens: Capillary Fingerstick Blood, Venous Whole Blood
Intended-use settings: physician office, home use, urgent care, hospital POC, emergency department
Operators: Anticoagulation clinic staff, medical assistants and nurses in waived settings; patients or caregivers for prescription home-use self-testing.
Comparator: Typically a laboratory PT/INR using a reference thromboplastin with a documented International Sensitivity Index, run on paired citrated venous plasma; a comparison with a cleared point-of-care INR device may be included but does not replace the laboratory reference.

CLIA Waiver Studies specifics

What Changes for This Assay on This Pathway.

Fingerstick sample application (volume, timing after lancing, strip handling) is the operator-dependent step; flex studies typically stress these along with strip and meter temperature and the interval from fingerstick to application.
Precision in untrained hands at anticoagulation and physician office sites is run on fingerstick samples and compared to the analytical claim.
Waived INR sites are predominantly anticoagulation clinics and physician offices whose staff may be highly practiced with a specific device; the study must enroll operators without laboratory training rather than only the clinic's most experienced users.

Endpoints the study must support

Method comparison of INR against the laboratory reference across the therapeutic and supratherapeutic ranges, with agreement in clinical categories (below range, in range, above range)
Imprecision at waived sites by untrained operators and, for self-testing claims, by patients
Agreement between fingerstick and venous whole blood on the device
For home-use claims, lay user agreement with the laboratory reference and labeling comprehension

Enrollment realities

Driven by coverage of the INR range, especially supratherapeutic values, which are a small fraction of anticoagulation clinic visits and must be actively captured. Self-testing arms add training and same-day laboratory logistics.

How Studybox runs it

Pre-Qualified Sites, Embedded Coordinators.

Waiver evidence depends on genuine intended-use operators in genuine waived settings. Our network of 100+ pre-qualified urgent care, physician office, and point-of-care sites already runs IVD protocols, so operator recruitment and site activation don't start from zero. How we run clia waiver studies →

Same assay, other pathways

Relevant FDA guidance

Our track record here

Studies Our Team Has Run for This Test Type.

Dual 510(k) + CLIA waiver · Hematology

Dual 510(k) and CLIA Waiver Study for a Point-of-Care Fingerstick PT/INR System

A point-of-care coagulation system that reports INR and prothrombin time in seconds from fresh capillary fingerstick blood, for warfarin monitoring in professional settings including CLIA-waived sites, was cleared and categorized as waived across a 0.8 to 8.0 INR reportable range. A study at 3–5 CLIA-waived sites with about 10 untrained operators, enrolling about 300 warfarin patients and about 150 healthy subjects, showed close agreement with a cleared point-of-care PT/INR device and with a laboratory coagulation analyzer, and precision held in untrained hands.

FAQ

Point-of-Care PT/INR Test Study Questions.

01 Who operates the point-of-care pt/inr test in a clia waiver studies study?

Anticoagulation clinic staff, medical assistants and nurses in waived settings; patients or caregivers for prescription home-use self-testing.

02 What is the comparator for a point-of-care pt/inr test study?

Typically a laboratory PT/INR using a reference thromboplastin with a documented International Sensitivity Index, run on paired citrated venous plasma; a comparison with a cleared point-of-care INR device may be included but does not replace the laboratory reference.

03 What drives enrollment for a point-of-care pt/inr test study?

Let's talk IVD research

Planning a point-of-care pt/inr test study?

Tell us the intended use and setting. We'll come back with a site plan, operator strategy, and a realistic activation timeline for the clia waiver studies pathway.