Horizon 2020 SME
FAQs

Ordering of H-FABP Tests and Visual scoring cards

How do I order tests?

  • Tests can be ordered through your distributor.
  • Questions about orders should be directed to your distributor.

How do I order Visual scoring cards?

  •  Visual scoring cards can be ordered through your distributor.

 

Usage, execution of the test

When should I use the test?

  • The test can be used to support the diagnosis of a suspected acute myocardial infarction (AMI). The test is intended for professional (General Practitioner) use. The test must be used from 3 hours until 18 hours after onset of symptoms.

The package is damaged, but the individual pouches are undamaged. Can I still use the test?

  • It is advised not to use tests of which the outer carton, pouches and/or parts are visually damaged.
  • Do not use tests of which the pouch has already been opened.

The test has been stored refrigerated, can it still be used?

  • Yes, but it is not required to store the test in the refrigerator. Therefore, the instructions for use state that the test should be stored between 2°C and 30°C at ambient conditions. Storage outside these condition limits is not allowed. Test performance of tests stored outside the condition limits cannot be guaranteed. When a test has been stored in the refrigerator it is advised to first let the test warm up to ambient temperature (15-25°C) ca. 10 min. before use.

The test has been stored frozen, can it still be used?

  • No, the test should be stored between 2°C and 30°C at ambient conditions, as specified in the instructions for use. Storage outside these condition limits is not allowed. Test performance of tests stored outside the condition limits cannot be guaranteed.

The expiry date of the test has passed, can I still use the test?

  •  No, do not use a test of which the expiry date has passed.

Onset of symptoms of AMI has been within 3 hours, can I use the test?

  • H-FABP can be elevated within one hour after AMI, therefore a positive result observed within 3 hours of onset of symptoms can be regarded as true positive. However not all infarctions, especially the smaller ones, show H-FABP values above the cut-off value. So false negative results can occur when the test is used too early.
  • When a test being used within 3 hours after onset of symptoms shows a negative result it is not possible to rule out AMI; a positive result can however be regarded as true positive.
  •  Diagnostic sensitivity and specificity have been evaluated using patient samples from 3 to 18 hours after onset of symptoms.

Onset of symptoms of AMI has been over 18 hours, can I use the test?

  • H-FABP can be elevated as long as 24 hours after AMI, so a positive result observed after 18 hours of onset of symptoms can be regarded as true positive.
  • False negative results however can occur when the test is used too late.
  • When a test being used later than 18 hours after onset of symptoms shows a negative result it is not possible to rule out AMI, a positive result can however be regarded as true positive.
  • Diagnostic sensitivity and specificity have been evaluated using patient samples from 3 to 18 hours after onset of symptoms.
  • In the clinical evaluation too few samples between 18 and 24 hours have been analyzed to draw any conclusions.

What is meant with ‘test initiation’?

  • When the blue cylinder of the Sampling Module is twisted down the sample will be transferred to the strip in the Cartridge to which the Sampling Module is connected and the flow of the sample through the strip will start. This is called ‘test initiation’.
  • The result should be read 5 minutes after having completely twisted down the blue cylinder.

I do not hear a click when I’ve twisted the blue part of the Sampling Module down completely.

  • There is no click. The blue part should be twisted down untill the stop.

The test does not start flowing after dispensing (docking and twisting down the blue part of the Sampling Module). What should I do?

  • Wait a few seconds, the test might start flowing a bit later.
  • When the flow does not start automatically, push down (and twist) the Sampling Module as far as possible into the Cartridge.
  • Try to twist the blue part of the sampling module up and down again.
  • Perform a new test.

There is no finger prick device in the package.

  • The finger prick device is not part of the test and should be provided by the user.

Which sample types can be analyzed with the test?

  • Only fresh whole blood which is obtained by a finger prick can be analyzed with the test.

Is it possible to analyze plasma with the test?

  • No, only fresh whole blood which is obtained by a finger prick can be analyzed with the test.

I’m having trouble obtaining enough blood using the finger prick.

  • The test should only be used when the sponge of the Sampling Module is fully saturated with blood. Complete saturation of the sponge can be verified by observation of the sponge through the transparent part of the sponge holder of the Sampling Module.
  • Use a bigger size lancet or increase depth of the finger prick device
  • Place patients hands under warm water and rub together
  • Hang hand down below waist
  • Grasp finger near area to be pricked and squeeze gently for three seconds
  • Place finger on table or firm surface to avoid moving while pricking
  • It is advised to first obtain a full droplet of blood capable of fully saturating the sponge before applying it to the sponge. Failing to do so, may results in enhanced red blood cell lysis and red background coloration of the test strip.

 

Test results, interpretation of test results

What does the ‘C’ on the cartridge mean?

  • The ‘C’ marks the position where the Control line should appear on the test strip.
    The appearance of the Control line indicates that the test has performed correctly. When no Control line appears the test is invalid.

What does the ‘T’ on the cartridge mean?

  • The ‘T‘ marks the position where the Test line should appear on the test strip.
    The appearance of the Test line indicates that the H-FABP level of the analyzed sample is elevated, which is an indication for AMI.

I’m not sure about the interpretation of the test (Positive / Negative).

  • Use the Visual Scoring Card as reference to determine whether the test result is Positive or Negative.
  • The diagnosis should always be based on the GP’s expertise, the H-FABP test is an aid in the diagnosis of an AMI.
  • If possible, repeat the test.

At 5 minutes the test was negative, but now I’ve read it again and now it’s positive.

  • The test result should be read at 5 minutes after test initiation. When a test result is read later than 5 minutes of test initiation, a false positive result can occur.

The test result is positive before 5 minutes after test initiation.

  • If a positive result is observed before 5 minutes after test initiation, the test result can be considered as positive.
  • For a negative call, read out should take place at 5 minutes after test initiation.
  • Based on a test result read before 5 minutes after test initiation it is possible to rule in AMI, it is however impossible to rule out AMI using test results read before 5 minutes after test initiation.

A red background appears which makes it difficult to interpret the test result at 5 minutes.

  • Red blood cells may have lysed during Sample preparation. Perform a new test if possible.
  • It is advised to first obtain a full droplet of blood capable of fully saturating the sponge before applying it to the sponge. Failing to do so, may results in enhanced red blood cell lysis and red background coloration of the test strip.

No Test and no Control line is visible at 5 minutes

  • Is there a flow (of sample through the strip in the cartridge) observed?
    Yes:       Test is invalid; please perform a new test if possible and report to FABPulous  or distributor.
    No:        Test did not start flowing (see “The test does not start flowing after   dispensing)

Test line is visible but no Control line is visible at 5 minutes

  • Test is invalid, perform another test if possible and report to distributor.
  • When it’s not possible to perform a new test regard the result as Positive.

 

Test performance

For technical questions about the FABPulous H-FABP rapid test or the marker H-FABP, please contact your distributor.

What does a diagnostic sensitivity of 93,6 % mean?

  • This means that 93,6 % of the patients eventually diagnosed with AMI are expected to have a positive test result.

What does a diagnostic specificity of 67,4 % mean?

  • This means that 67,4 % of the patients eventually not diagnosed with AMI are expected to have a negative test result.

What is the cut-off H-FABP concentration of the test?

  • The cut-off is 4 ng/ml; this is the concentration that will give 95% chance of detection.

What can cause false negative test results?

A false negative result, in the sense that although the patient underwent an AMI no elevated H-FABP level is detected by the test, can be caused by amongst others:

  • The test being performed before 3 hours or later than 18 hours after onset of symptoms. Before 3 hours H-FABP level may have not reached the cut-off level (4 ng/ml) of the test yet. After 18 hours the H-FABP level may have dropped again below the cut-off level.
  • Small variability in sensitivity of the test due to small variations in the production process. This may lead to H-FABP levels just above the cut-off not being detected. In production it is monitored that a H-FABP level of 4 ng/ml has a detection probability of at least 95%.
  • Biological variation. A very small AMI with minor H-FABP release may result in a H-FABP level below the  cut-off.

What can cause false positive test results?

A false positive result, in the sense that although the patient underwent no AMI an elevated H-FABP level is detected by the test, can be caused by:

  • Test results being read later than 5 minutes after test initiation. The development of the test line signal intensity marginally continues after 5 minutes. The test result should be read at 5 minutes after test initiation.
  • Kidney problems. In healthy persons H-FABP is present at low levels in the blood plasma and is filtered out of the plasma by the kidneys. When the renal function is impaired (low eGFR, < 30), elevated H-FABP levels can occur.
    Renal function decreases with increase of age. Older persons have a bigger chance of false positives due to impaired renal function.
  • Elevated H-FABP levels could also indicate  myocardial cell damage other than AMI.

Are there any medication or biological components which interfere with the test (results)?

  • There are no indications that there are any drugs or biological components which interfere with the test (results).
  • For the following drugs it has been demonstrated that they do NOT interfere in the test at their maximum therapeutic concentrations: Acenocoumarole, acetaminophen, acetylsalicylic acid, amoxicilline, atorvastatin, diclofenac, doxycyclin, furosemide, hydrochlorothiazide, ibuprofen, metformin, metoprolole, naproxen, nitrofurantoin, omeprazole, oxazepam, simvastatin and temazepam.
    Other drugs have not been subjected to interference testing.
  • For the following biological components it has been demonstrated that they do NOT interfere in the test at the concentrations mentioned: Triglycerides (3000 mg/dl), hemoglobin (300 μM), bilirubin (491μM) and cholesterol (20 mM).
    Other biological components have not been subjected to interference testing.
  • No cross-reactivity occurs with other FABP-subtypes that are not heart specific.

What is included in the package?

The package contains the following parts:

  • one pouch with a sampling module
  • one pouch with a cartridge
  • an instructions for use
  • The finger prick device is not included in the package and should be provided by the user.
  • The Visual scoring card is not included in the package and can be ordered through your distributor.

Can the test be reused?

  • No, the test can be used only once.
  • Also when a negative results has been obtained, the test can be used only once.

How do I dispose of used tests?

  • Used tests contain human blood sample that must be treated as infectious and should be decommissioned as such. The test device does not contain chemicals in such concentration that other specific guidelines have to be followed.