Science & evidence

Technical findings for a research workflow.

The study summarized here evaluates post-staining analytical stability. Its findings inform research workflow discussions under the tested conditions; they do not establish diagnostic performance or patient outcomes.

Technical-stability study

Follow the same technical tests over time.

The study followed separately prepared technical tests from an early acquisition through later post-staining measurements.

Semen specimensBiorepository samples in the technical study

Technical testsIndependently pipetted preparations

2.5

Minute originReference acquisition for each test

Dilute in TNE30 s denaturationAcridine-orange stainCold hold at 4–8°CSerial acquisitionSDF-Index analysis

Multiple technical tests came from the same specimens. The 70 preparations should not be read as 70 independent specimen donors.

The 60-minute observation

Read the mean alongside retention and discordance.

At 60 minutes, the mean DFI change was +1.04 percentage points relative to origin. Individual results varied: 81.4% were within ±5 percentage points, and 21.4% had a different DFI category.

+1.04 ppDFI mean changerelative to 2.5-minute origin

81.4%DFI within ±5 ppat 60 minutes

21.4%DFI category discordanceat 60 minutes

0.946DFI Lin concordanceat 60 minutes

DFI mean changeHDS mean change15–60 minute interval

Mean changes relative to each test’s 2.5-minute origin. Lines connect the measured timepoints; they do not show individual-test variability. Solid line/circles: DFI. Dashed line/squares: HDS.

Technical interpretationThe observations support a practical post-staining acquisition window of up to 60 minutes under the evaluated conditions. The group mean does not imply every result stayed within tolerance or retained its category.

All evaluated timepoints

Later measurements show greater DFI drift.

Both retention and category discordance are shown alongside the mean changes and concordance. The 120- and 240-minute observations were exploratory.

DFI and HDS changes relative to a 2.5-minute origin, by time after staining
Time after staining	DFI mean Δ vs origin	DFI Lin CCC	HDS mean Δ vs origin	HDS Lin CCC	DFI within ±5 pp	DFI category discordance
15 min	+0.11 pp	0.973	−0.50 pp	0.984	91.4%	15.7%
30 min	+0.28 pp	0.959	−0.68 pp	0.981	87.1%	17.1%
60 min	+1.04 pp	0.946	−0.81 pp	0.972	81.4%	21.4%
120 min	+3.40 pp	0.797	−1.05 pp	0.948	76.7%	30.0%
240 min	+6.42 pp	0.652	−1.20 pp	0.936	58.3%	48.3%

pp = percentage points. CCC = Lin’s concordance correlation coefficient. HDS retention within ±5 percentage points was 100% at every evaluated timepoint. DFI category discordance includes observations near category boundaries. The table summarizes the supplied study findings; it does not display confidence intervals or per-timepoint denominators.

Scope of the evidence

An analytical-stability study with defined limits.

What was evaluated

Post-staining measurement stability
Agreement with an early origin
Retention within a practical tolerance
Research category reproducibility over time

What was not established

Clinical sensitivity or specificity
A patient diagnosis
Treatment selection or effectiveness
Pregnancy or live-birth outcomes

Applying the findings

Evaluated protocol and instrument conditions matter
Technical replicates and specimens are distinct
Mean agreement does not describe every result
Each laboratory evaluates its research workflow

Study context

Review the methods behind the numbers.

This summary draws on the technical-stability study materials supplied to Varen. Contact us for the available methods and supporting technical information when assessing the workflow for your research.

FRAGSIGN and SDF-Index are For Research Use Only. Not for use in diagnostic procedures.

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Ask about the evaluated workflow conditions, analysis methods, and available study materials.

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