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Does the thermometer still work? When to replace items in your first aid kit at home

CNA Lifestyle checks with the experts on when to replace items such as plasters, medicine and even masks – because a lot of these expire after a couple of years.

When was the last time you took a good look inside your first aid kit at home? (No, rifling through for a surgical mask doesn’t count.) Was it a few months back? More than a year ago?

Maybe your first aid kit isn’t a box but a pouch or spare drawer with odds and ends rattling around inside, along with bandages, plasters, an assortment of blister packs, and bottles of mixtures from … you can’t remember when.

READ: Are expired toiletries and beauty products still effective and safe to use?

Not knowing what’s in your medical kit at home isn’t a good idea because some items may have shorter shelf lives than others. And having a messy drawer or cabinet worsens the situation because you can’t keep track of its contents. 

"The shelf life for items in a first aid kit is usually about two to three years, depending on the item," said Sucy Mathew, a senior nurse manager with SingHealth Polyclinics-Marine Parade. "It is necessary to conduct regular checks on the items in a first aid kit to ensure that the items have not expired and to have them replaced if expired."

We find out more from the experts what things you should be replacing from your first aid kit at home.


These are just pieces of non-woven material with elastic loops at the ends. Surely these can’t expire, right?

Well, masks do. “All unused disposable masks generally expire in one to three years (and a maximum five years) after the date of manufacture,” said Dr Gan Heng Hui, a senior specialist in Food Chemistry & Safety from Nanyang Polytechnic’s School of Chemical & Life Sciences.

She added that the expiry date only applies if the masks are not opened and are stored in proper conditions.

“The expired masks could lose their effectiveness or may have attracted micro-organisms, resulting in irritations and skin infections,” she explained. “If the mask is dirty or damaged, or the breathing resistance is unacceptably high, it should be disposed of.”

When to replace: If the packaging is already opened, you should dispose the mask, especially when the mask has discoloured or if the foam strips inside have crumbled, said Dr Gan. Using such expired masks would result in you breathing in the disintegrated particles.


Bandages are fine to use as long as they are individually packed, and remain sealed and undamaged, said Elissa Wong, a senior pharmacist from Khoo Teck Puat Hospital (KTPH).

But once the packaging is broken, microbes may enter and the bandages become something you don’t want to use directly on open cuts and wounds.

(Photo: Pixabay/Heung Soon)

As for plasters, they may or may not come with shelf-life recommendations, said Wong. But don’t assume they last forever. For one, they may lose their adhesiveness. “If you have purchased sterile plasters, the wound pad may become contaminated over time,” she said.

When to replace: For both bandages and plasters, check for damaged, discoloured or mouldy packaging. If you are not sure whether the item has been compromised, replace it to be safe, advised Wong.

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Stick to the expiry date religiously, said Dr Wong Li Lian, a senior lecturer with the Department of Pharmacy, Faculty of Science at National University of Singapore. 

It may seem like a waste but when medicines have passed the expiry date, they may degrade, lose their efficacy and even potentially become unsafe, she said. “Some of these products may cause irritation, rashes or infection.”

Another reason to chuck those expired tablets or cough mixture: You can’t tell if they’re still effective just by appearance. “It is not possible to tell which expired medication is safe for consumption without laboratory tests,” said Dr Wong.

When to replace: If a medicine has noticeably changed its texture, smell or colour, or has developed a film or spots, it should be discarded regardless of expiry date. “The molecules in these products can break down and form other molecules that may cause a bad reaction when used,” she said.


Similar to oral medications, it is not recommended to use topical products such as medicated oil, antiseptic cream and muscle pain relief ointment past their expiration dates, said KTPH’s Wong. The chemical components of the preparation may degrade or lose its stability, thereby compromising the safety and efficacy of the product, she added.

When to replace: “Topical products should be discarded if they emit weird odours, or have discoloured or changed in physical appearance,” said Wong.


When it comes to your digital thermometer's accuracy, the battery condition shouldn’t affect it, according to the World Health Organization (WHO).

In fact, the WHO noted that these devices should still provide accurate readings “after being stored and/or transported in an environment of -20 degrees Celsius to 50 degrees Celsius, and a relative humidity of 15 per cent to 95 per cent non-condensing for one month” – which covers most situations in Singapore.


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As for glucometers and blood pressure monitors, they are expected to last two to three years on average if they are well maintained, said Wong. “It is advisable to send your device for servicing every one to two years (or as indicated on the device’s website or instruction manual) to ensure correct functioning and accuracy.” 

Also, pay attention to the accessories, such as the inflatable cuff that accompany your blood pressure machine; they are expected to require more frequent replacement with regular use, said Wong.

(Photo: Pixabay/Steve Buissinne)

If you use a glucometer with a test strip, note that most of the strips may be stored in their original packaging up to the expiry date stated on the product.

“Once the packaging is opened, the shelf life may be reduced, ranging from three to six months. This is due to the reagents that are used in the test strips,” said Wong. And you want to use strips that have not expired to ensure the test results' accuracy.

But no matter what device you use, "to prolong a gadget’s shelf life, patients can remove the batteries when not in use," advised SingHealth Polyclinic's Mathew.

When to replace: If you haven't used your digital thermometer until recently, don't take the initial "Lo" reading on the display as low battery. It just means that the ambient temperature the thermometer is reading is beyond what it is programmed to register. For most digital thermometers, a blinking battery icon is what signals low battery. It is also time to change the battery if the thermometer doesn't start or if it doesn’t give the beep sound.

But if the display is cracked, damaged or not displaying well despite having a good battery, whether it’s a digital thermometer, glucometer or blood pressure monitor, it's time to get a new device. 

“If you suspect your device is inaccurate, bring it along on your next doctor’s visit so you can compare the measurements,” advised Wong. If you use a glucometer with a test strip, it should be replaced if it has been exposed to moisture and heat, or air for prolonged periods of time.

Source: CNA/bk