Frequently Asked Questions
Assignment
Four copies of the assignment sheet are enclosed:
- The original form is signed and returned with the box
- Three copies to remain at the clinic (e.g. for the ward, patients’ files, microbiology)
What information does the assignment sheet contain?
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a short medical history questionnaire
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patient-specific QR codes
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signature of the attending physician
Is a patient consent form required?
The attending physician uses the form enclosed in the box to commission Noscendo GmbH. A patient’s consent form is not required as DISQVER is not a genetic investigation according to the German Genetic Diagnostics Act (GenDG).
Does DISQVER have approval from the ethics committee?
No approval from the ethics committee is necessary, because DISQVER is a medical device bearing the CE mark.
What information does Noscendo need from the clinic?
Prior to commissioning, Noscendo needs the following information:
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Contact of clinical microbiology department
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Contact of the attending physician
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In case of sample collection: DHL Medical Express pick-up address
Sampling
How much blood is needed?
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One standard blood draw
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Fill the enclosed blood tubes with 5-10 ml blood
Are there limitations or rejection criteria for the samples?
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Heparin blood tubes are not suitable, as they can influence the sample preparation process.
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In case of multiple blood collection, the Cell-Free DNA BCT® (Streck) tubes should be filled after EDTA and before heparin tubes (according to the manufacturer’s specifications).
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Peripheral venous extraction of blood is preferred.
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Other blood collection sites are not rejected or have limited disadvantages.
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Tubes with less than 5 ml blood.
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Blood tubes that are damaged as a result of poor packaging.
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Use of expired blood tubes.
What are the blood draw instructions?
What are the blood draw instructions?
What blood draw equipment can be used?
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Any common blood collection sets (butterfly cannulas with tube)
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BD Safety-Lok™ blood collection set 21 G 3/4 (order no. 367282)
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BD Vacutainer one-use holder (order no. 364815)
Is it possible to use other blood tubes?
No, because:
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The blood tubes contain a liquid that enables stable storage of the cell-free DNA in the whole blood at room temperature for up to one week.
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Furthermore, the blood tubes enclosed in the DISQVER box are labelled with a Noscendo bar code for pseudonymisation and tracing purposes.
Can other samples also be tested?
No. The test is currently validated for cell-free DNA from patients’ whole blood.
Sample dispatch
What does the DISQVER box contain?
The standardised DISQVER processes ensure high quality standards. The DISQVER box overpack is labelled with a use-by date and a unique barcode. It contains:
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Return box with box bar code, absorbent bag, plastic bag in accordance with UN3373 and a cool pack
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Two blood tubes with sample bar QR code for whole blood to stabilise the cell-free DNA (Cell-Free DNA BCT®, Streck)
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Blood collection and shipment instructions
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Assignment sheet with report QR code.
How is the box to be stored until blood collection? How are the samples stored in the box until shipment?
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The box can be stored at room temperature before and after blood collection until shipment.
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The cool pack intended for return shipment should be cooled to 4°C before dispatch and added to the box shortly before shipment.
How do I send the box?
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Request pick-up of the samples in the Noscendo portal.
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Take the return boxes to the DHL Medical Express pick-up address or hand them over to a DHL courier.
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Please note the individual collection times of the pick-up addresses.
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In case of an in-house laboratory, the samples are transferred to the trained staff there.
Results
How are the results communicated?
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The attending physician is sent an email stating that the DISQVER report is complete.
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The DISQVER report can then be accessed via the link in the email, via the QR code on the assignment form or via the QR code on the individual patient stickers in the Noscendo portal.
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The DISQVER report is generated as a list of positively tested pathogens or as a negative result, so that it can be assessed with knowledge of the other patient results.
How long does it take to get the result?
Depending on the limiting factors of shipment and sequencing, the DISQVER report can currently be transmitted 36–44 hours after shipment.
In case of an in-house laboratory, there is no dispatch time and reports can be sent within 24 hours.
How should the number of reads be interpreted?
As a general rule, more reads being detected means more cfDNA of a pathogen was present at the time the sample was taken.
Noscendo and clinical background
Who are we?
Noscendo GmbH is an IVD stand-alone software company from Germany which focuses on the reliable, efficient and fast detection of pathogens in patients’ blood.
What clinical studies have been carried out on the DISQVER pathogen diagnostics?
In collaboration with Heidelberg University Hospital, the Noscendo founders have already successfully completed two clinical studies (Grumaz et al. Genome Medicine, 2016; Grumaz et al. CCM, 2019).
What is DISQVER?
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DISQVER is the Noscendo CE-IVD pathogen test based on NGS (next-generation sequencing) for detecting bloodstream infections.
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With a hypothesis-free approach that is open to any results, DISQVER enables the detection of bacteria, fungi, DNA viruses and parasites from a standard blood sample without prior cultivation or prior knowledge in relation to the infection or the causative pathogen.
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DISQVER uses proprietary databases and relevance assessments to enable differentiation between commensals, contaminations and infections and makes it possible for you to make an informed decision.
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DISQVER represents a new generation of pathogen diagnostics and enables an entirely new perspective in the treatment of bloodstream infections.
How does DISQVER work?
- Blood sample: the cell-free DNA from the patient’s blood is prepared for sequencing.
- Sequencing: the sample is sequenced using parallel sequencing (next-generation sequencing, NGS).
- Bioinformatic analysis: the reads from the sequencing are categorised into human and non-human reads. Microbial reads are compared with a proprietary database with over 16,000 genomes and the signals are assessed in terms of their relevance.
- DISQVER report: the relevance assessment enables a statistical evaluation and differentiation between commensals or contaminations and pathogens. The differentiation between infectious pathogens, which may only be present in small numbers, and contaminations, which are often present in larger number, is calculated automatically on the basis of the non-human reads in the patient sample.
Which patients is DISQVER suitable for?
DISQVER can be used in all patients for whom it is ethically acceptable to take 5-10 ml of blood (generally patients with a body weight of at least 10 kg).
Using DISQVER in young children or younger patients requires prior consultation with the physician. The patients’ state of health and the risk-benefit balance of taking blood should be the main considerations.
Which indications is DISQVER suitable for?
DISQVER can be used to identify pathogens in patients who have already been diagnosed with a bloodstream infection (possibly with prior negative pathogen diagnostics) and to exclude an infection for preventive testing of patients who belong to a risk group for severe infections (e.g. progress monitoring after transplantations or oncology patients).
In a 2019 pilot study, DISQVER was successfully tested for acute and severe infections (sepsis, peritonitis, pneumonia, severe local infections), oncology (solid tumours and haematological oncology) and cardiology (including endocarditis).
Typical indication areas are:
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Cardiology (e.g. acute/subacute endocarditis, patients with LVAD device and a suspected infection)
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Transplantations (e.g. progress monitoring after transplantation)
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Acute and severe infections (severe cases of sepsis, peritonitis, pneumonia, for example)
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Oncology/haematology-oncology (e.g. leukaemia – cases with neutropenic fever, neutropenia, fever of unknown origin)
Scientific background
What is cell-free DNA and where does it come from?
Cell-free DNA (cfDNA) occurs naturally in the blood (Aucamp et al. Biol. Rev., 2018). Human cfDNA from the natural renewal process of dying cells and cfDNA from commensals can be detected in the blood. In the event of an infection, this natural background noise is supplemented by the cfDNA of the infectious pathogens, which is released as the immune system fights and kills the pathogens (Grumaz et al., Genome Medicine, 2016).
How stable is cell-free DNA?
On the basis of human sample material, cfDNA has been shown to have a very short half-life of only approximately 30 minutes to 2 hours (Khier and Lohan, Future Sci., 2018). This short half-life of cfDNA in the blood allows DISQVER to present an accurate picture of the infection present at the time the sample was taken.
For DISQVER, the samples are taken in Cell-Free DNA BCT® (Streck) blood collection tubes to stabilise the cell-free DNA.
Why does DISQVER use cell-free DNA?
Cell-free DNA (cfDNA) represents a new molecule class in diagnostics, and, with the help of the latest high-throughput sequencing technologies, it constitutes an unprecedented opportunity to identify pathogens quickly, specifically and with high sensitivity.
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The analysis thus presents an approach without hypotheses that is open to any results (no PCR panel that is restricted to a selection of particular pathogens) – independently of the growth of pathogens in the blood culture.
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Initial comparisons with culture-based procedures and extrapolations have shown that cfDNA is considerably more abundant than individual pathogens in the patient’s blood.
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Real-time analysis (infection status at the time blood was taken).
What is the relationship between cell-free DNA and infection? Is the amount of cell-free DNA in the blood always the same, regardless of the origin or severity of the infection?
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Regardless of the origin of the infection, pathogens can be identified on the basis of cell-free DNA in the blood, e.g. in the case of pulmonary, abdominal or urogenital sepsis (Grumaz et al. CCM, 2019).
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DISQVER can provide information on the progress of an infection by means of changes of relevant to non-relevant hits over time (Grumaz et al 2016/2019).
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In preventive testing of risk patients, the DISQVER test can be used to detect pathogens of an incipient infection early on (Grumaz et al 2016/2019).
What is the laboratory procedure and how long does it take?
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Whole blood is centrifuged, causing the plasma to separate from the erythrocytes
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The cfDNA is isolated from the plasma.
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Sequencing of all cfDNA fragments.
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The laboratory process currently takes approximately 24 hours from receipt.
What sequencers are used?
The Noscendo lab uses and recommends Illumina sequencers.
Can you use DISQVER in your own laboratory?
Yes. DISQVER can also be used in in-house laboratories. The Noscendo lab team provides extensive consulting and training to ensure that the same standards are upheld. DISQVER is then used by means of software into which the sequencing data generated in the lab is uploaded.
Bioinformatic background
Is there a CE mark and what does the CE marking cover?
DISQVER is a CE-marked medical device. As stand-alone software, DISQVER is SaMD (Software as Medical Device), classified as ‘other IVD’ under 98/79/EC (IVDD). The CE mark and the patents of DISQVER cover the bioinformatic processes, or more precisely, the software for analysing microbial nucleic acids in the blood and assessing their relevance.
Does DISQVER determine an absolute number of pathogens?
The absolute number of pathogens is not determined. DISQVER provides information on significantly elevated pathogens in the patient’s blood, which are detected on the basis of fragments of cell-free DNA in the bloodstream and not on the basis of living colony-forming units (CFUs). This means that analysis is still possible even after treatment with anti-infective agents has begun.
What pathogen classes are detected?
DISQVER detects pathogens by performing comparisons with a database of over 16,000
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bacteria
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DNA viruses
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fungi
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parasites.
In addition to the high-precision detection of pathogens, DISQVER enables in particular precise differentiation between contamination or commensals and the actual infection.
What makes DISQVER different from blood culture and conventional methods of analysis?
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Higher positivity rate thanks to use of cell-free DNA and innovative bioinformatics.
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Precise measurement of the germ load at the time the blood sample was taken thanks to the short half-life of cfDNA.
Do you want to find out more or
test DISQVER?
Then get in touch with us!
Christian Lohmann
+49 2066 50687-70
