The permitted Acceptable Quality Level (AQL) for medical gloves is 1.5, with an inspection level of GI.

The production batch is sampled according to sampling plans defined in ISO2859-1. For example, a production batch consisting of between 10001 and 35000 gloves would require the testing of 125 gloves. Out of the 125 gloves a maximum of 5 leaking gloves would be allowed and 6 or more leaking gloves would cause the batch to fail.

In cases where the batch number is not known; for example, if a Notified Body is required to carry out a Type Test, then EN455-1:2000 specifies that 200 gloves shall be tested, in which case 7 leaking gloves are allowed and 8 or more leaking gloves would cause the batch to fail.
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Dimensions of surgical gloves

Size	Minimum Length (mm)	Width (mm)
5	250	67±4
5.5	250	72±4
6	250	77±5
6.5	250	83±5
7	250	89±5
7.5	250	95±5
8	250	102±6
8.5	250	108±6
9	250	114±6
9.5	250	121±6

Dimensions of examination gloves

Size	Minimum Length (mm)		Width (mm)
	Seamed gloves	Unseamed gloves
Extra small	270	240	£80
Small	270	240	80±10
Medium	270	240	95±10
Large	270	240	110±10
Extra-large	270	240	³110

The second assessment is based upon a measurement of the force at break of dumb-bell test specimen cut from gloves, before and after accelerated ageing at 70°C for 7 days.

13 samples are tested from each batch and the median force at break must be above the following minimum values:

Gloves must meet a minimum force at break defined by the following table;

	Surgical gloves		Examination gloves
	Latex	Synthetic	Latex	Other Materials
Before accelerated ageing (N)	12	9	9	3.6
After accelerated ageing (N)	9	6	6	3.6

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The essential requirements of the Directive require products to be safe when used by the end-user.

Latex Protein

Part 3 of EN455 covers the biocompatibility of medical gloves and in particular introduced a test method for the measurement of latex protein in natural rubber gloves.

The test method is based upon a modified Lowry protein assay, in which gloves are extracted with a buffer solution, containing hemisodium TES (N-tris-[hydroxymethyl]-methyl-2-aminoethanesulfonic acid, disodium salt). The gloves are shaken with the buffer for 1 hour and then the protein in the extract is precipitated from solution. The precipitate is collected by centrifugation and re-dissolved with O.1M sodium hydroxide. This solution is then treated with Bio-Rad protein assay reagent and the resulting blue coloured complex measured by colorimetry.

This method enables a comparison of the total protein content of natural rubber gloves. The limit of detection is typically less than 50 mg/g of rubber.

EN455 provides an alternative method for the determination of latex protein in the event that other components of the rubber formulation interfere with the modified Lowry method. This alternative method is based on the use of high pressure liquid chromatography (HPLC) that measures the individual amino acids which make up the latex protein. This HPLC method takes a longer time to complete and is more complicated than the modified Lowry method, so although the measurement of protein by this method is more reliable and gives the best correlation with clinical data on latex protein reactions, the modified Lowry is still defined as the standard method for measurement of latex protein.

At present there is insufficient data to indicate what level of latex protein presents a hazard of sensitisation.

Non-latex Protein Allergens

EN455-3 specifies that a list of other materials present in the glove that are capable of causing allergic reaction shall be supplied upon request by the user or other relevant body.

Endotoxins

If product is claimed to be “low endotoxin content”, EN455-3 also specifies that sterile gloves shall be subject to monitoring of endotoxin levels to establish that the endotoxin content does not exceed a maximum limit of 20 endotoxin units per pair of gloves.

Endotoxins are toxic materials which are present in the cell walls of certain types of bacteria (gram negative). These toxins remain on the gloves even though the bacteria have been killed by the sterilisation process.

Endotoxins are a type of pyrogen, which means that they can cause fever and other adverse reactions in humans. Therefore, excessive levels of endotoxin can cause post-operative problems in patients who have undergone surgery.

The test for endotoxins is based upon the Limulus Amoebocyte Lysate (LAL) test. This test uses an extract from the blood of the horseshoe crab, in which the endotoxin suppresses the natural clotting mechanism of the extract. A series of diluted extracts from gloves is placed in a small test tube with a measured amount of the extract. The test tubes are examined to establish which concentrations suppress the formation of a clot. In this way an estimate of the amount of endotoxin can be obtained.

In some cases, chemicals from the gloves may interfere with this test, in which case the standard permits an alternative test to be carried out. This test is a rabbit pyrogen test. In the rabbit pyrogen test, extracts from the glove are injected into rabbits and their body temperature measured. If a pyrogen (endotoxin) is present, a significant increase in the rabbits’ body temperature will be observed.
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This harmonised standard encompasses all mercury containing thermometers constructed from glass except those for special purposes (such as ovulation thermometers).

The key performance requirement set down by the standard is that the thermometers shall have an accuracy of +0.1°C and -0.15°C between 35.5°C and 42.0°C. This is demonstrated by comparison to a highly accurate reference thermometer at a series of temperatures.

Additional requirements include that the thermometer scale and numbering are uniform and easily legible, the thermometer bulb must not break away from the body under a force of fifty Newtons and that the glass that the thermometer is constructed from must have certain physical characteristics and be free from defects.

Concern has been expressed in the media regarding the safety of mercury containing thermometers. Guys Hospital Poison Centre has informed us that the danger from swallowed mercury is negligible. This is because the human body is exceptionally bad at absorbing mercury through the gut; swallowed mercury is excreted before it causes harm. The main risk from mercury lies in inhalation of mercury vapours over a long time period.
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This standard applies to any thermometer utilising a series of chemical dots that have been designed to change appearance in order to indicate temperature.

The key performance requirement set down in the standard is that the thermometers shall have an accuracy of between +0.1°C and -0.2°C across its indicated range. This is demonstrated by comparison to a highly accurate reference thermometer at a series of temperatures.

Additional requirements include that the thermometer indicates temperature every 0.1oC, that the change in appearance of the chemical dots should be distinct, that the thermometer must hold the reading for at least 20 seconds and that the thermometer must be able to regenerate (i.e. return to working condition after use).
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This Standard applies to any thermometer with a digital readout and an internal power supply that does not provide continuous measurement or is intended for measurement of temperature of the skin.

The key performance requirement set down by this standard is that the thermometers shall have an accuracy of ±0.1°C between 35.5°C and 42.0°C. This is demonstrated by comparison to a highly accurate reference thermometer at a series of temperatures.

Additional requirements include a stable response with time, resistance to thermal and physical shocks and the incorporation of a self testing mechanism to ensure correct working prior to use.
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There is currently no European standard available for liquid crystal thermometers. BM Polyco uses an American (ASTM) standard to help demonstrate conformity.

Liquid crystal thermometers are constructed from a series of liquid crystal cells attached to a plastic strip. Each liquid crystal cell is formulated to change colour within a certain temperature range so that they provide a continuous measuring scale.

The standard specifies that the thermometer must measure across the range 32°C to 38°C, accurate to within ±0.6°C, and the thermometer must be supplied with detailed instructions as laid out in the standard.

BM Polyco meet the performance requirements of this standard by immersing six liquid crystal thermometers from every batch into a waterbath and slowly increasing the waterbath temperature. As the temperature increases the colour change of the liquid crystals is recorded and compared with the reading of a highly accurate calibrated thermometer.
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BM Polyco swabs containing cotton are tested for compliance with this standard. Non-woven swabs that do not contain cotton are not covered by this standard. However, in the absence of other guidance the safety and performance requirements for cotton and cotton/viscose swabs are used. The draft standard specifies values for the absorptive capacity of the swabs, their acidity/alkalinity, sinking time (rate of absorption), water and ether extractables, and ignition residues.
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The British Pharmacopoeia is a document that was originally used to store the formulation details of generic medicines and the production requirements for certain medical devices. As standards bodies introduce standards for these medical devices they are removed from the Pharmacopoeia. The British Pharmacopoeia defines several types of swab:

Gauze Swab; An absorbent cotton and viscose gauze folded into rectangles of 8 – 32 ply with no cut edges exposed. Requirements are provided

X-Ray-Detectable Gauze Swab; a gauze swab into which is incorporated a distinctly coloured yarn securely heat bonded to an x-ray detectable component.

The general requirements for these swabs are identical to those given in the draft EN 14079 standard (above). Additionally x-ray detectable swabs must give equivalent x-ray opacity as a material containing 55% barium sulphate. In order to demonstrate this requirement swabs must be sent out to a hospital to be x-rayed as part of the quality control process.
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This harmonised standard states that a device can only be labelled sterile if there is less than a one in a million chance of product containing micro-organisms. The standard does not contain test methods or methods of sterilisation but directs the manufacturer to use a ‘validated sterilisation process’ such as that described by EN 1174.
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The process of sterilisation destroys any micro-organisms living on a product. However, if the product packaging is inadequate micro-organisms from the environment can reach the product and re-colonise it, rendering it non-sterile. Additionally, the sterilisation process can damage incorrectly selected packaging leading to an undesirable change in properties and/or appearance.

The EN868 series of standards provide guidance on the correct packaging to use when sterilising products using a variety of techniques.
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This harmonised standard gives the basic requirements for any information supplied with a medical device. This includes the use of the sterile symbol, labelling of lot and use by dates, legibility and a number of other information requirements. The standard also directs the manufacturer to refer to other standards applicable to their product as these may give additional labelling requirements.
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An important component of product certification is the identification and, where possible, measurement of the effect that the product has upon human tissue. This standard deals with the identification and measurement of these hazards. Assessment of these hazards and their associated risks can then be conducted according to EN1441 or EN ISO 14971.

Some of the effects this standard series examines include:

Cytotoxicity; the propensity of the device to kill or slow the growth of cells.

Irritation; the propensity of the device to irritate the skin, eyes or other area.

Systemic toxicity; the propensity to cause a number of effects including fever.
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This standard encompasses the risk analysis process given in EN 1441 and provides additional guidance on the use of a vigilance system to monitor the product after it has been released into the marketplace. Data from this in-use monitoring is then fed back into the design and risk assessment processes leading to improvements in product safety.

This standard will supersede EN1441:1998 during March 2004.
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EN1174 is a series of standards that give guidance on the selection and use of microbiological methods to determine an estimated level of micro-organisms on a medical product. This data is used during sterilisation to establish that irradiation will produce a sterile product.
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