earlier (never use slides used for examining acid fast bacilli for the same purpose). Infected Glassware Contaminated material—may be disposed in paper or cardboard wrappers and incinerated.
11. Quaternary ammonium compounds are active against
both gram-positive and gram-negative species but are
not effective against spores and mycobacteria. They
are used for sterilizing food utensils in restaurants and
hotels and for disinfecting blankets in hospitals.
12. Glutaraldehyde (Cidex) affects even spores and
mycobacteria. It is employed as 2% solution and is
recommended for sterilizing cystoscopes, etc.
13. Ethylene oxide gas is being widely used to sterilize
disposable plastic syringes, petri dishes, etc.
Grade A glassware needs no testing. Grade B is satisfactory
for most routine work. Others should be heat resistant,
have a low coefficient of expansion and be free from
soluble metals and free alkali; in addition, they should be
New: Look for cracks if any. Soak in 2% HCl for overnight to
neutralize any alkali present. Wash in running water. Boil
in synthetic detergent for 30 minutes, rinse in tap water
and finally in distilled water.
Used glassware should be rinsed immediately after use.
Boil in a detergent for 30 minutes and clean thoroughly with
a brush, rinse in tap water and finally in distilled water. Dry
them in the oven with temperature not exceeding 80°C.
Dissolve 25 g potassium dichromate in 25 mL of water. Add
50 mL concentrated sulfuric acid (slowly, always add acid
to water and not (vice-versa), cool, store it in a stoppered
bottle; discard when it starts turning green.
¾ Autoclave to remove infected material
¾ Rinse in running water, let dry
¾ Rinse in methylated spirit, let dry
¾ Soak in chromic acid solution overnight
¾ Dry on suction pump using methylated spirit, or ether,
¾ To sterilize—plug mouth piece with nonabsorbent
cotton wool, wrap in kraft paper and hot air sterilize
¾ Autoclave to remove infected material
¾ Boil in detergent solution for 30 minutes
¾ Rinse in running water, rinse in distilled water and place
them in a wire basket upside down and dry in an oven
¾ Cotton plug them and sterilize in the hot air oven.
¾ Wash as before (as for test tubes).
¾ Dry quickly to avoid corrosion
¾ Sterilize metal caps and their bottles in hot air oven
¾ Boil in a detergent for 30 minutes
¾ Place in dichromate for overnight
¾ For using, take them out with a forceps and hold them
¾ Should be autoclaved and then cleaned as mentioned
earlier (never use slides used for examining acid fast
bacilli for the same purpose).
Contaminated material—may be disposed in paper or
cardboard wrappers and incinerated.
Autoclave the glassware that has been contaminated.
Having autoclaved, wash and prepare in the usual way.
Complete bacterial sterility can be achieved either by
sterilizing them in the hot air oven or in an autoclave.
Keep injection syringes separate from blood withdrawing
syringes. Fresh syringes (sterilized) should be used
for withdrawing blood for each patient. Before reusing
them, clean them properly and then sterilize them.
Needles used should be sharp and not with blunted
Choice of Syringes and Needles
All glass syringes are preferred over glass and metal ones.
Preferably keep size 5 mL or more syringes for withdrawing
blood. Needles should be of size equal to or less than 21
(SWG). A needle with a smaller diameter would cause lysis
of blood when used for blood withdrawing. Withdrawing
needles should be at least an inch long.
These are washed in the usual way. Dried with acetone.
Wrap the plunger and the barrel in a paper and sterilize in
Immediately after use, wash them thoroughly with cold
water (hot water will coagulate proteins and will make
the syringes difficult to clean). Clean them thoroughly in
a detergent, brush the barrel properly, rinse in tap water
and then in distilled water. Rinse in acetone and let dry.
Sterilize in hot air oven as mentioned above.
These should be washed at first with cold 2% lysol solution
and then clean as above. Syringes infected with highly
virulent material should at first be autoclaved. The syringes
should be placed in the cold oven and be heated at 160°C
for 90 minutes. Syringes not used for 3 months should be
Glass Barrel and Metal Plunger Syringes
The only precaution to be taken here is that metal corrosion
should be avoided and the barrel and the plunger should
be sterilized separately (kept in a wrapper) by autoclaving
34 Concise Book of Medical Laboratory Technology: Methods and Interpretations Needles
¾ Should first be rinsed in cold water
¾ Clean the mounts with a cotton-wool swab
¾ Wash again, rinse in acetone
¾ Pass a stylet through the hole to remove any plugs if
(It is important to discard all needles with blunted tips,
a hand lens can be used to examine needle tips)
¾ Serum hepatitis and HIV can be transmitted through
using imperfectly cleaned and sterilized needles
¾ The needle should be sterilized in hot air oven.
Disinfection of Syringes by Boiling
In an emergency, syringes can be effectively sterilized by
boiling them in distilled water for at least 5 minutes after
having cleaned them in the usual way.
This is the world and time of disposables. In the interest
of the patient every laboratory should ideally use disposable syringes only.
As far as possible use disposable, sterilized plasticware instead of glassware.
(Commercially available from Bioshields)
Air, land and water are the essential elements around
which diverse life forms our planet “Earth” thrive and
Precious human life needs to be protected against the
challenge mounted by microbes in day to day life as well
as professional settings of infectious agents. Build up of
Comments
Post a Comment
اكتب تعليق حول الموضوع