General Laboratory Knowledge

MDL 102

What is the primary role of clinical laboratory testing?

the detection, diagnosis, and treatment of disease

What are the main duties of a Medical Laboratory Scientist (MLS) or Medical Laboratory Technician (MLT)?

Collecting and processing specimens

-chemical, biological, hematologic, immunologic, microscopic, molecular diagnostic, and microbial testing

-Preparing blood for transfusion

-Analyzing and communicating results to physicians or other primary care providers

T or F: The clinical laboratory should assume a role of leadership and education when tests are being ordered to help health care providers understand the best pattern for ordering tests

T

What is a "Core Laboratory"?

a current trend in laboratory organization where several departments share a workspace

-often combines routine hematology, transfusion, and clinical chemistry

What is the function of the Blood Bank/Transfusion Medicine department?

to study and prepare blood products for transfusion

What is the function of the Clinical Chemistry department?

performs quantitative analysis of constituents (like glucose) on various specimens such as blood serum, urine, and other body fluids

-may also include toxicology to analyze drugs

What is the function of the Hematology and Hemostasis department?

studies the formed elements of the blood (e.g., red blood cells, white blood cells, and platelets) and performs blood coagulation tests

What is the function of the Immunology and Serology department?

the testing of antigens and antibodies in blood serum

What is the function of the Microbiology department?

the detection of microorganisms that cause disease (pathogens)

What is Molecular Diagnostics?

a field that applies the principles of basic molecular biology to the study of human diseases

-provides information for applications like gene therapy and genetic screening

-usually predictive

Besides a central hospital laboratory, what are some alternate sites for laboratory testing?

Point-of-Care Testing (POCT): Testing performed at the patient’s bedside, in operating rooms, or recovery areas

Reference Laboratories: Outside laboratories where specimens for more complex or infrequently ordered tests are sent. This is often more cost-effective for smaller labs

Physician Office Laboratories (POLs): Where minor lab tests (e.g., urinalysis, pregnancy tests) are performed for a physician's own patients

Home Testing: Tests performed by the patient at home

What is "informed consent" in a healthcare context?

the patient is aware of, understands, and agrees to the nature of the testing to be performed and what will be done with the reported results

What is the difference between "implied" and specific written consent for laboratory procedures?

Implied consent generally occurs when a patient enters a hospital or lab; this covers many routine procedures, such as a venipuncture (blood draw)

Specific written consent is required for more complex procedures, such as a bone marrow aspiration or a lumbar puncture for cerebrospinal fluid (CSF) collection

What is the Hazard Communication Standard?

A standard requiring chemical manufacturers, distributors, or importers to provide Safety Data Sheets (SDSs) for each chemical to communicate hazards

ensures consistent presentation of chemical information and requires employers to make SDSs accessible to employees.

What is a biohazard?

Infectious materials/agents that present a (potential) risk to the health of human beings or animals in the laboratory, either through direct infection or through the environment.

What is biosafety?

The practice of reducing the risk of unintentional exposure to pathogens and toxins or their accidental release.

Describe the four biosafety levels.

BSL-1: Least hazardous with minimal risk for healthy adults

BSL-2: Moderate hazards, works with indigenous microorganisms causing diseases of varying severity

BSL-3: Works with potentially lethal microorganisms that may be transmitted through respiration

BSL-4: Highest level, deals with dangerous exotic microorganisms with high risk of aerosol transmission and fatal infections

What are standard precautions?

Safety precautions from the CDC concerning the handling of all patient specimens. All blood and body substances (fluids) are considered equally infectious (Universal Precautions).

What is personal protective equipment (PPE)?

Specialized clothing or equipment worn by an employee for protection against a hazard. Proper donning and doffing are essential for infection control.

What is disinfection?

The elimination of pathogenic microorganisms (except bacterial spores) on inanimate objects, usually done by liquid chemicals like household bleach or wet pasteurization in healthcare settings.

What are the requirements for sharps containers?

- Closable, puncture resistant, and leakproof on sides and bottom

- Accessible, maintained upright, and not allowed to overfill

-Labeled or color-coded

- Colored red or labeled with the biohazard symbol

- Labeled in fluorescent orange or orange-red with contrasting lettering/symbols

What is an aerosol?

An airborne infectious particle.

What are biosafety cabinets?

Protective workplace devices used to control the presence of infectious agents in the air. They're used for procedures that generate aerosols, use high-efficiency particulate air filters, and sterilize air via heat or UV.

What are the different classes of fires?

Class A: Ordinary combustibles Class B: Flammable liquids and gases Class C: Electrical equipment Class D: Powdered metal (combustible) material Class E: Cannot be extinguished

What is the proper order of priorities in first aid?

Stop bleeding, prevent shock, treat wound - in that order.

How should you treat alkali or acid burns in the eye?

Wash out the eye thoroughly with running water for a minimum of 15 minutes, holding the eyelid open. An eye fountain is recommended, but any running water will suffice. Notify a physician immediately while washing the eye.

How should you handle heat burns?

- Apply cold running water or ice in water to relieve pain and stop tissue damage

- Use a wet dressing - Apply bandage securely but not tightly

- For third-degree burns, don't use ointments or grease, and consult a physician immediately

What are SI Units?

International System of Units used in laboratories, related to the metric system. Used for standardization between labs.

Why must lab results include both numbers and units?

To express the complete measurement with precision and to ensure results can be interpreted correctly.

What are significant figures/digits?

Digits of a number that express the precision of the measurement from which the number is derived.

What is the difference between volumetric and graduated pipettes?

Volumetric pipettes are designed to deliver a single fixed volume with high accuracy, while graduated pipettes have multiple calibration marks for delivering various volumes.

What is the difference between MOHR and SEROLOGICAL pipettes?

MOHR pipettes are calibrated between two marks on the stem, while SEROLOGICAL pipettes have graduation marks down to the delivery tip and drain faster due to larger orifice.

What is a TC (to-contain) pipette?

A pipette calibrated to contain a specified amount of liquid. Requires rinsing with diluting fluid to ensure all contents are emptied.

What is a TD (to-deliver) pipette?

A pipette calibrated to deliver the exact amount of fluid designated when held vertically, with a small amount remaining in the tip that should not be expelled.

What is a blowout pipette?

A pipette where the drop remaining in the tip must be "blown out" into the receiving vessel. These have an etched ring near the suction opening.

How do you read the meniscus correctly?

For clear solutions, read the bottom of the meniscus. For colored or viscous solutions, read the top of the meniscus. Always keep the eye at the level of the meniscus.

What is the proper method for cleaning glassware?

1. Wash with brush in detergent solution

2. Rinse in tap water

3. Rinse in distilled water

What is the maximum temperature for drying measuring glassware in an oven?

Never more than 100°C for measuring (volumetric) glassware.

What should you NEVER do when pipetting?

NEVER pipette by mouth! Always use a pipetting aid like a rubber suction bulb.

How should broken glassware be handled?

NEVER pick up broken glassware with your fingers. Use the provided dustpan and broom. Dispose in special receptacle, not regular garbage.

What is the role of analytical balances in clinical laboratories?

Analytical balances are essential for accurate mass measurement in clinical laboratories, offering high precision (0.0001g) needed for chemical measurements and reagent preparation.

What are the general rules for using an analytical balance?

1. Set up free from vibration

2. Close the case before reading

3. Never weigh chemicals directly on the pan

4. Clean any spills immediately 5. Transfer weighed materials to labeled containers immediately

How do top-loading balances differ from analytical balances?

Top-loading balances are faster and easier to use but offer less precision than analytical balances. They are used when high analytical precision isn't required, such as when preparing large volumes of reagents.

What is laboratory reagent grade water?

Water suitable for specified laboratory procedures that doesn't interfere with the specificity, accuracy, or precision of assay procedures. It has inorganic and organic impurities removed.

What are the three types of laboratory reagent water?

Type I: Purest form, used for standard solutions and precise measurements

Type II: Used for general laboratory tests and qualitative procedures

Type III: Used for urinalysis, glassware washing, and as source for preparing other water types

classified using max. colony count (CFU/mL), pH, and silica count

What applications require Type I reagent water?

- Preparation of standard solutions, buffers, and controls

- Quantitative analytical procedures (especially nanogram measurements) - Electrophoresis

- Toxicology screening tests

- High-performance liquid chromatography

How should reagent water be stored?

- Type I: Must be used immediately after production to prevent CO2 absorption

- Types II and III: Can be stored in borosilicate glass or polyethylene bottles but should be used quickly

- All containers should be tightly stoppered to prevent gas absorption

What are the main methods for purifying water in laboratories?

- Deionization

- Distillation

- Reverse osmosis

- Filtration and adsorption

- Combinations of these methods

How does deionization purify water?

Water passes through a resin column with positively and negatively charged particles that combine with and remove ions present in the water. Additional treatments may be needed to remove organic impurities and microorganisms.

How does distillation purify water?

Water is boiled and the resulting steam is cooled and condensed. This removes iron, magnesium, calcium, and microorganisms but doesn't remove volatile impurities like carbon dioxide, chlorine, and ammonia.

What is reverse osmosis in water purification?

The passage of water under pressure through a semi-permeable membrane that removes approximately 90% of dissolved solids, 98% of organic impurities, insoluble matter, and microorganisms, but only about 10% of ionized particles.

Name the equipment labelled 1-5

1. Bunsen Burner

2. Retort Stand

3. Clay Triangle

4. Clamp

5. Evaporating Dish

Name the equipment labelled 6-10

6. Ring Clamp

7. Mortar and Pestle

8. Test Tube

9. Beaker

10. Gas/Reagent Bottle

Name the equipment labelled 11-15

11. Wire Gauze

12. Safety Goggles

13. Cork Stoppers

14. Watch Glass

15. Erlenmeyer Flask

Name the equipment labelled 16-20

16. Tongs

17. Rubber Stoppers

18. Burette

19. Pipette

20. Thermometer

Name the equipment labelled 21-25

21. Graduated Cylinder

22. Wash Bottle

23. Transfer Pipette

24. Dropper

25. Test Tube Holder

Name the equipment labelled 26-30

26. Lab Burner

27. Forceps

28. File

29. Wire Brush

30. Test Tube Rack

Name the equipment labelled 31-35

31. Funnel

32. Spatula

33. Scoopula

34. 24-Well Tray

35. Crucible and Cover