Test tube

Last updated
Test tube
Two small test tubes held in spring clamps.jpg
Two small test tubes held in spring clamps
Other namesCulture tube
Uses Chemical reaction
Related items Vacutainer
Boiling tube
Centrifuge tube

A test tube, also known as a culture tube or sample tube, is a common piece of laboratory glassware consisting of a finger-like length of glass or clear plastic tubing, open at the top and closed at the bottom.

Contents

Test tubes are usually placed in special-purpose racks.

Types and usage

Louis Lumiere with a microscope and some test tubes Louis Lumiere with microscope and test tubes.jpg
Louis Lumière with a microscope and some test tubes

Chemistry

Test tubes intended for general chemical work are usually made of glass, for its relative resistance to heat. Tubes made from expansion-resistant glasses, mostly borosilicate glass or fused quartz, can withstand high temperatures up to several hundred degrees Celsius.

Chemistry tubes are available in a multitude of lengths and widths, typically from 10 to 20 mm wide and 50 to 200 mm long. [1] The top often features a flared lip to aid pouring out the contents.

A chemistry test tube typically has a flat bottom, a round bottom, or a conical bottom. Some test tubes are made to accept a ground glass stopper or a screw cap. They are often provided with a small ground glass or white glaze area near the top for labelling with a pencil.

Test tubes are widely used by chemists to handle chemicals, especially for qualitative experiments and assays. Their spherical bottom and vertical sides reduce mass loss when pouring, make them easier to wash out, and allow convenient monitoring of the contents. The long, narrow neck of test tube slows down the spreading of gases to the environment.

Test tubes are convenient containers for heating small amounts of liquids or solids with a Bunsen burner or alcohol burner. The tube is usually held by its neck with a clamp or tongs. By tilting the tube, the bottom can be heated to hundreds of degrees in the flame, while the neck remains relatively cool, possibly allowing vapours to condense on its walls. A boiling tube is a large test tube intended specifically for boiling liquids.

A test tube filled with water and upturned into a water-filled beaker is often used to capture gases, e.g. in electrolysis demonstrations.

A test tube with a stopper is often used for temporary storage of chemical or biological samples.

Samples of human blood collected for blood tests Blood test.jpg
Samples of human blood collected for blood tests

Biosciences

Culture tubes are test tubes used in biology and related sciences for handling and culturing all kinds of live organisms, such as molds, bacteria, seedlings, plant cuttings, etc.. Some racks for culture tubes are designed to hold the tubes in a nearly horizontal position, so as to maximize the surface of the culture medium inside.

Culture tubes for biology are usually made of clear plastic (such as polystyrene or polypropylene) by injection molding [2] and are often discarded after use. Plastic test tubes with a screwtop cap are often called "Falcon tubes" after a line manufactured by Becton Dickinson. [3]

Some sources consider that the presence of a lip is what distinguishes a test tube from a culture tube. [4]

Clinical medicine

In clinical medicine, sterile test tubes with air removed, called vacutainers, are used to collect and hold samples of physiological fluids such as blood, urine, pus, and synovial fluid. These tubes are commonly sealed with a rubber stopper and often have a specific additive placed in the tube with the stopper color indicating the additive. For example, a blue-top tube is a 5  ml test tube containing sodium citrate as an anticoagulant, used to collect blood for coagulation and glucose-6-phosphate dehydrogenase testing. [5] Small vials used in medicine may have a snap-top (also called a hinge cap) molded as part of the vial.

Vacutainer/sample tube types for venipuncture/phlebotomy   edit
Tube cap color or type in order of drawAdditiveUsage and comments
Blood culture bottleSodium polyanethol sulfonate (anticoagulant) and growth media for microorganismsUsually drawn first for minimal risk of contamination. [6] Two bottles are typically collected in one blood draw; one for aerobic organisms and one for anaerobic organisms. [7]
Light blue Sodium citrate (weak calcium chelator/anticoagulant)Coagulation tests such as prothrombin time (PT) and partial thromboplastin time (PTT) and thrombin time (TT). Tube must be filled 100%.
Plain redNo additiveSerum: Total complement activity, cryoglobulins
Gold (sometimes red and grey "tiger top" [8] )Clot activator and serum separating gel [9] Serum-separating tube (SST): Tube inversions promote clotting. Most chemistry, endocrine and serology tests, including hepatitis and HIV.
OrangeClot activator and serum separating gel [10] Rapid serum-separating tube (RST).
Dark greenSodium heparin (anticoagulant)Chromosome testing, HLA typing, ammonia, lactate
Light greenLithium heparin (anticoagulant) Plasma . Tube inversions prevent clotting
Lavender ("purple") EDTA (chelator / anticoagulant) Whole blood : CBC, ESR, Coombs test, platelet antibodies, flow cytometry, blood levels of tacrolimus and cyclosporin
PinkEDTA (chelator / anticoagulant) Blood typing and cross-matching, direct Coombs test, HIV viral load
Royal blueEDTA (chelator / anticoagulant)Trace elements, heavy metals, most drug levels, toxicology
TanEDTA (chelator / anticoagulant) Lead
Gray Glucose , lactate [12]
Yellow Acid-citrate-dextrose A (anticoagulant) Tissue typing, DNA studies, HIV cultures
Pearl ("white")Separating gel and (K2)EDTA PCR for adenovirus, toxoplasma and HHV-6

Other uses

Test tubes are sometimes put to casual uses outside of lab environments, e.g. as flower vases, glassware for certain weak shots, or containers for spices. They can also be used for raising queen ants during their first months of development.

Variants

Boiling tube

A boiling tube is a small cylindrical vessel used to strongly heat substances in the flame of a Bunsen burner. A boiling tube is essentially a scaled-up test tube, being about 50% larger.

They are designed to be wide enough to allow substances to boil violently as opposed to a test tube, which is too narrow; a boiling liquid can explode out of the end of test tubes when they are heated, as there is no room for bubbles of gas to escape independently of the surrounding liquid. This phenomenon is called bumping.

Ignition tube

An illustration of a setup using an ignition tube. The ignition tube is being heated by the Bunsen burner on the left, with the heated gas escaping from the tube to the pan via the delivery tube on top and at right. Ignition Tube.png
An illustration of a setup using an ignition tube. The ignition tube is being heated by the Bunsen burner on the left, with the heated gas escaping from the tube to the pan via the delivery tube on top and at right.

An ignition tube is used in much the same way as a boiling tube, except it is not as large and thick-walled. It is primarily used to hold small quantities of substances which are undergoing direct heating by a Bunsen burner or other heat source. [13] This type of tube is used in the sodium fusion test.

Ignition tubes are often difficult to clean due to the small bore. When used to heat substances strongly, some char may stick to the walls as well. They are usually disposable.

See also

Eight-cavity culture-tube mold (Lake Charles Manufacturing) Tube mold.gif
Eight-cavity culture-tube mold (Lake Charles Manufacturing)

Related Research Articles

<span class="mw-page-title-main">Bunsen burner</span> Laboratory device used to make fire from fuel and oxidizer gases

A Bunsen burner, named after Robert Bunsen, is a kind of ambient air gas burner used as laboratory equipment; it produces a single open gas flame, and is used for heating, sterilization, and combustion.

<span class="mw-page-title-main">Bain-marie</span> Device for double boiling, often used for cooking and material creation

A bain-marie, also known as a water bath or double boiler, a type of heated bath, is a piece of equipment used in science, industry, and cooking to heat materials gently or to keep materials warm over a period of time. A bain-marie is also used to melt ingredients for cooking.

<span class="mw-page-title-main">Laboratory glassware</span> Variety of equipment usually made of glass used for scientific experiments

Laboratory glassware refers to a variety of equipment used in scientific work, and traditionally made of glass. Glass can be blown, bent, cut, molded, and formed into many sizes and shapes, and is therefore common in chemistry, biology, and analytical laboratories. Many laboratories have training programs to demonstrate how glassware is used and to alert first–time users to the safety hazards involved with using glassware.

<span class="mw-page-title-main">Phlebotomy</span> Medical procedure involving an incision in a vein

Phlebotomy is the process of making a puncture in a vein, usually in the arm, with a cannula for the purpose of drawing blood. The procedure itself is known as a venipuncture, which is also used for intravenous therapy. A person who performs a phlebotomy is called a phlebotomist, although most doctors, nurses, and other technicians can also carry out a phlebotomy. In contrast, phlebectomy is the removal of a vein.

Fractional distillation is the separation of a mixture into its component parts, or fractions. Chemical compounds are separated by heating them to a temperature at which one or more fractions of the mixture will vaporize. It uses distillation to fractionate. Generally the component parts have boiling points that differ by less than 25 °C (45 °F) from each other under a pressure of one atmosphere. If the difference in boiling points is greater than 25 °C, a simple distillation is typically used. It is used to refine crude oil.

<span class="mw-page-title-main">Venipuncture</span> Process of obtaining intravenous access

In medicine, venipuncture or venepuncture is the process of obtaining intravenous access for the purpose of venous blood sampling or intravenous therapy. In healthcare, this procedure is performed by medical laboratory scientists, medical practitioners, some EMTs, paramedics, phlebotomists, dialysis technicians, and other nursing staff. In veterinary medicine, the procedure is performed by veterinarians and veterinary technicians.

<span class="mw-page-title-main">Vacutainer</span> Type of blood collection equipment for medical testing

A vacutainer blood collection tube is a sterile glass or plastic test tube with a colored rubber stopper creating a vacuum seal inside of the tube, facilitating the drawing of a predetermined volume of liquid. Vacutainer tubes may contain additives designed to stabilize and preserve the specimen prior to analytical testing. Tubes are available with a safety-engineered stopper, with a variety of labeling options and draw volumes. The color of the top indicates the additives in the vial.

<span class="mw-page-title-main">Funnel</span> Pipe with a wide top and narrow bottom

A funnel is a tube or pipe that is wide at the top and narrow at the bottom, used for guiding liquid or powder into a small opening.

<span class="mw-page-title-main">Stopper (plug)</span> Conical closure used to seal a container

A stopper is a cylindrical or conical closure used to seal a container, such as a bottle, tube or barrel. Unlike a lid or bottle cap, which encloses a container from the outside without displacing the inner volume, a bung is partially or wholly inserted inside the container to act as a seal. Synonyms are bung and cork. A bung can be defined as "a plug or closure used to close an opening in a drum or barrel. It is called a plug when referring to a steel drum closure."

<span class="mw-page-title-main">Closure (container)</span> Devices and techniques used to close or seal a bottle, jug, jar, tube, can, etc.

A closure is a device used to close or seal a container such as a bottle, jug, jar, tube, or can. A closure may be a cap, cover, lid, plug, liner, or the like. The part of the container to which the closure is applied is called the finish.

<span class="mw-page-title-main">Laboratory flask</span>

Laboratory flasks are vessels or containers that fall into the category of laboratory equipment known as glassware. In laboratory and other scientific settings, they are usually referred to simply as flasks. Flasks come in a number of shapes and a wide range of sizes, but a common distinguishing aspect in their shapes is a wider vessel "body" and one narrower tubular sections at the top called necks which have an opening at the top. Laboratory flask sizes are specified by the volume they can hold, typically in metric units such as milliliters or liters. Laboratory flasks have traditionally been made of glass, but can also be made of plastic.

<span class="mw-page-title-main">Vial</span> Small glass vessel or bottle used in laboratories or hospitals

A vial is a small glass or plastic vessel or bottle, often used to store medication in the form of liquids, powders, or capsules. They can also be used as scientific sample vessels; for instance, in autosampler devices in analytical chromatography. Vial-like glass containers date back to classical antiquity; modern vials are often made of plastics such as polypropylene. There are different types of vials such as a single dose vial and multi-dose vials often used for medications. The single dose vial is only used once whereas a multi-dose vial can be used more than once. The CDC sets specific guidelines on multi-dose vials.

<span class="mw-page-title-main">Round-bottom flask</span>

Round-bottom flasks are types of flasks having spherical bottoms used as laboratory glassware, mostly for chemical or biochemical work. They are typically made of glass for chemical inertness; and in modern days, they are usually made of heat-resistant borosilicate glass. There is at least one tubular section known as the neck with an opening at the tip. Two- or three-necked flasks are common as well. Round bottom flasks come in many sizes, from 5 mL to 20 L, with the sizes usually inscribed on the glass. In pilot plants even larger flasks are encountered.

<span class="mw-page-title-main">Eye dropper</span> Device used to transfer small quantities of liquids

An eye dropper, also called Pasteur pipette or simply dropper, is a device used to transfer small quantities of liquids. They are used in the laboratory and also to dispense small amounts of liquid medicines. A very common use was to dispense eye drops into the eye. The commonly recognized form is a glass tube tapered to a narrow point and fitted with a rubber bulb at the top, although many styles of both plastic and glass droppers exist. The combination of the pipette and rubber bulb has also been referred to as a teat pipette. The Pasteur pipette name is from the French scientist Louis Pasteur, who used a variant of them extensively during his research. In the past, there was no equipment to transfer a chemical solution without exposing it to the external environment. The hygiene and purity of chemical compounds is necessary for the expected result of each experiment. The eye dropper, both glass and plastic types, can be sterilized and plugged with a rubber bulb at the open end of the pipette preventing any contamination from the atmosphere. Generally, they are considered cheap enough to be disposable, however, so long as the glass point is not chipped, the eye dropper may be washed and reused indefinitely.

<span class="mw-page-title-main">Heating mantle</span>

A heating mantle, or isomantle, is a piece of laboratory equipment used to apply heat to containers, as an alternative to other forms of heated bath. In contrast to other heating devices, such as hotplates or Bunsen burners, glassware containers may be placed in direct contact with the heating mantle without substantially increasing the risk of the glassware shattering, because the heating element of a heating mantle is insulated from the container so as to prevent excessive temperature gradients. Heating mantles may have various forms. In a common arrangement, electric wires are embedded within a strip of fabric that can be wrapped around a flask. The current supplied to the device, and hence the temperature achieved, is regulated by a rheostat. This type of heating mantle is quite useful for maintaining an intended temperature within a separatory funnel, for example, after the contents of a reaction have been removed from a primary heat source.

<span class="mw-page-title-main">Condenser (laboratory)</span> Laboratory apparatus used to condense vapors

In chemistry, a condenser is laboratory apparatus used to condense vapors – that is, turn them into liquids – by cooling them down.

<span class="mw-page-title-main">Reflux</span> Condensation of vapors and their return to where they originated

Reflux is a technique involving the condensation of vapors and the return of this condensate to the system from which it originated. It is used in industrial and laboratory distillations. It is also used in chemistry to supply energy to reactions over a long period of time.

<span class="mw-page-title-main">Reagent bottle</span> Laboratory storage container

Reagent bottles, also known as media bottles or graduated bottles, are containers made of glass, plastic, borosilicate or related substances, and topped by special caps or stoppers. They are intended to contain chemicals in liquid or powder form for laboratories and stored in cabinets or on shelves. Some reagent bottles are tinted amber (actinic), brown or red to protect light-sensitive chemical compounds from visible light, ultraviolet and infrared radiation which may alter them; other bottles are tinted blue or uranium green for decorative purposes -mostly vintage apothecary sets, from centuries in which a doctor or apothecary was a prominent figure. The bottles are called "graduated" when they have marks on the sides indicating the approximate amount of liquid at a given level within the container. A reagent bottle is a type of laboratory glassware. The term "reagent" refers to a substance that is part of a chemical reaction, and "media" is the plural form of "medium" which refers to the liquid or gas which a reaction happens within, or is a processing chemical tool such as a flux.

<span class="mw-page-title-main">Evaporating dish</span>

An evaporating dish is a piece of laboratory glassware used for the evaporation of solutions and supernatant liquids, and sometimes to their melting point. Evaporating dishes are used to evaporate excess solvents – most commonly water – to produce a concentrated solution or a solid precipitate of the dissolved substance.

<span class="mw-page-title-main">Teclu burner</span> Variant of the Bunsen burner

The Teclu burner is an ambient air laboratory gas burner, that was created by Romanian chemist Nicolae Teclu in 1882. The burner is most commonly used to heat substances in a laboratory, can be used for sterilisation and sometimes it is used for soldering or glasswork. It is commonly made from brass or iron.The burner physically consists of a round base, a tube connected to it providing the gas to the flame and a vertical metal tube that directs the flame upwards. The tube has a conical shape closer to the base.

References

  1. MiniScience.com catalog: Test Tube, accessed March 27, 2009.
  2. M. Jeremy Ashcraft; General Manager; Lake Charles Manufacturing (2007). Test Tube Molding Process: A discussion on the molding of plastic test tubes. Lake Charles Manufacturing.
  3. "BD Falcon Tubes and Pipets" (PDF). Becton Dickinson . Retrieved 14 March 2016.
  4. Thomas Scott (transl., 1996), Concise Encyclopedia: Biology. Walter de Gruyter. ISBN   3-11-010661-2, ISBN   978-3-11-010661-9. 1287 pages.
  5. TheFreeDictionary > blue top tube. Citing: McGraw-Hill Concise Dictionary of Modern Medicine. 2002 by The McGraw-Hill Companies, Inc.
  6. Pagana, KD; Pagana, TJ; Pagana, TN (19 September 2014). Mosby's Diagnostic and Laboratory Test Reference - E-Book. Elsevier Health Sciences. p. xiii. ISBN   978-0-323-22592-2.
  7. "Chapter 3.4.1: Blood cultures; general detection and interpretation". Clinical Microbiology Procedures Handbook. Wiley. 6 August 2020. ISBN   978-1-55581-881-4.
  8. "Test Tube Guide and Order of Draw" (PDF). Guthrie Laboratory Services. June 2019.
  9. "Specimen requirements/containers". Pathology & Laboratory Medicine, UCI School of Medicine. Retrieved 2020-09-10.
  10. "Proper Order of Draw" (PDF). Memorial Lab Services. Retrieved 2023-06-15.
  11. Castellini MA, Castellini JM, Kirby VL (1992). "Effects of standard anticoagulants and storage procedures on plasma glucose values in seals". J Am Vet Med Assoc. 201 (1): 145–8. PMID   1644639.
  12. Amitava Dasgupta; Jorge L. Sepulveda (20 July 2019). Accurate Results in the Clinical Laboratory: A Guide to Error Detection and Correction. Elsevier Science. p. 131. ISBN   978-0-12-813777-2.
  13. Nichols, William Ripley (1877). An Elementary Manual of Chemistry: Abridged from Eliot and Storer's Manual, with the Co-operation of the Authors. Ivison, Blakeman, Taylor.