The Evidence Guide provides advice on assessment and must be read in conjunction with the performance criteria, required skills and knowledge, range statement and the Assessment Guidelines for the Training Package.

Overview of assessment

Critical aspects for assessment and evidence required to demonstrate competency in this unit

Assessors should ensure that candidates can:

follow enterprise standards, procedures and practices

prepare suitable samples

recognise, identify and document significant sample characteristics

set up a light microscope for optimal resolution

maintain personal safety and that of others

minimise cross-contamination and contamination of the laboratory and environment.

Context of and specific resources for assessment

This unit of competency is to be assessed in the workplace or simulated workplace environment.

This unit of competency may be assessed with:

MSL922001A Record and present data

MSL933002A Contribute to the achievement of quality objectives

MSL943002A Participate in laboratory/field workplace safety

MSL953001A Receive and prepare samples for testing.

Resources may include:

standard laboratory equipped with appropriate equipment, such as light microscopes and samples

enterprise procedures, standard methods and materials.

Method of assessment

The following assessment methods are suggested:

observation of the candidate performing microscopic examinations

review of data records prepared by the candidate, such as counts, observations and results

feedback from supervisors and peers about adherence to enterprise/technical procedures

questioning to assess underpinning knowledge.

In all cases, practical assessment should be supported by questions to assess underpinning knowledge and those aspects of competency which are difficult to assess directly.

Where applicable, reasonable adjustment must be made to work environments and training situations to accommodate ethnicity, age, gender, demographics and disability.

Access must be provided to appropriate learning and/or assessment support when required.

The language, literacy and numeracy demands of assessment should not be greater than those required to undertake the unit of competency in a work like environment.

This competency in practice

Industry representatives have provided the case studies below to illustrate the practical application of this unit of competency and show its relevance in a workplace setting.

Construction materials testing

The supply of river sand is running out and quarries are accessing alternative sources of sand for use in concrete mixes in construction. The sand should not be an aggregate that is likely to break down into smaller particles. A technician in a quarry company is required to analyse samples of crushed rock using a light microscope. The technician looks for characteristics of the sample, such as angularities, roundness, sharpness, cracks, presence of organic matter, mineral structure and whether the particles are a conglomerate. If the sample does not meet the characteristics, the company will need to treat it to make it suitable for use in concrete mixes (for example by washing, crushing and sieving).

Food processing

A customer complaint is received about the baking properties of a flour delivery. The laboratory assistant at the flour mill is given the task of testing the starch content of the suspect flour. He/she prepares iodine stained samples of the returned flour and a range of baked and partially baked products prepared from it. First, the assistant makes up fresh iodine staining solution and then prepares slides of each sample for microscopic examination. He/she identifies the characteristic starch granules of the flour sample and records the degree of gelatinisation in the starch granules in the baked samples. He/she discusses the results with the supervisor and prepares a report for the customer.

Biomedical

A laboratory assistant works in the microbiology laboratory of a public hospital and is responsible for preparing and staining sputum smears from patients for micro and culture. The assistant puts on a clean gown and gloves before collecting the specimens from the reception area of the laboratory. The assistant prepares cultures of the sputum specimens on simple and selective media before preparing, fixing and staining smears for microscopic examination. The results are checked by the supervisor, entered into the laboratory information management system (LIMS) and sent to the appropriate section of the hospital.

Environmental

A laboratory assistant prepares media for plant tissue culture. There has been some contamination of Gram-positive bacteria in the last two batches and the supervisor has initiated an overhaul of the preparation and aliquotting procedure. The laboratory assistant has been asked to follow the new procedure exactly and to remove samples at each stage of ingredient addition for microscopic examination. The laboratory assistant records the exact addition amounts, batch numbers and brands of the reagents, the location of the addition (which biohazard cabinet), the equipment used and the pre-sterilisation records of all equipment.

The laboratory assistant then prepares slides, fixes them and performs a Gram stain on each of the aliquots removed from the new preparation run. Microscopic analysis of each aliquot reveals nil contamination. The supervisor decides that there has been a breach in the old procedure and the laboratory assistant is asked to follow the new procedure and to perform a routine microscopic check on all batches for the next month.

Required skills

Required skills include:

setting up the workbench and microscope ergonomically

setting up, cleaning and using a light microscope to achieve optimum resolution of the specimen

using personal protective clothing and other safety equipment correctly

performing counts on samples

performing basic measurements using grids

logging and tracking samples through all steps from receiving a sample through to completion of a procedure and reporting

interpreting and recording test results, including simple calculations

correctly handling and storing samples and equipment

Required knowledge

Required knowledge includes:

parts and functions of a light microscope

importance and appropriate use of controls and certified reference materials

hazards and risks in laboratories associated with performing microscopic examination

enterprise and/or legal traceability requirements

relevant health, safety and environment requirements

Specific industry

Additional knowledge requirements may apply for different industry sectors. For example:

Biological industry:

basic structure and function of cells and organelles

basic classes and classification of organisms of organisms, such as prokaryotes, eukaryotes, plants, animals, bacteria, viruses and prions

cell physiology and processes, such as simple and facilitated diffusion, plasmolysis, osmosis, tonicity, active transport, energy production, mitosis, motility, phagocytosis and pinocystosis

purposes and mechanisms of staining (e.g. Gram +ve and -ve)

The range statement relates to the unit of competency as a whole. It allows for different work environments and situations that may affect performance. Bold italicised wording, if used in the performance criteria, is detailed below. Essential operating conditions that may be present with training and assessment (depending on the work situation, needs of the candidate, accessibility of the item, and local industry and regional contexts) may also be included.

Codes of practice

Where reference is made to industry codes of practice, and/or Australian/international standards, it is expected the latest version will be used

Standards, codes, procedures and/or enterprise requirements

Standards, codes, procedures and/or enterprise requirements may include:

Australian and international standards, such as:

AS ISO 17025-2005 General requirements for the competence of testing and calibration laboratories

AS/NZS ISO 9000 Set:2008 Quality management systems set

AS/NZS 2243 Set:2006 Safety in laboratories set

principles of good laboratory practice (GLP)

Australian code of good manufacturing practice for medicinal products (GMP)

safety manuals

quality manuals and equipment and procedure manuals

standard operating procedures (SOPs)

material safety data sheets (MSDS)

enterprise recording and reporting procedures

production and laboratory schedules

material, production and product specifications

Preparation of samples

Preparation of samples may include:

aseptic transfer of specimen

centrifugation

cooling

drying

filling a counting chamber in one continuous flow without bubbles or overflow

filtration

fixing of films to minimise cell damage and the production of artefacts

labelling

mounting of stained films, sections and whole mounts to ensure long term preservation

permanent labels for smears, films and sections for presentation, storage and retrieval

physical or chemical separation

selection of diluent to preserve or enhance visibility of the cells to be counted

selection, filling and cover slipping of a clean, dry counting chamber to ensure even distribution of cells during filling

serial dilution to enable individual cells to be reliably counted

staining of fixed material to illustrate required characteristics

sub-sampling

thin film or smear on a slide

Checking sample condition

Checking sample condition may include:

labelling

spillage

spoilage due to incorrect storage and transport conditions

temperature control

suitability for the examination

Pre-use checks

Pre-use checks may include:

calibration

cleaning/checking use by dates of reagents

routine maintenance

Equipment

Equipment may include:

glass slides

counting chambers (e.g. haemocytometer)

optical graticules and stage micrometers

tissue culture flasks

Light microscopes

Light microscopes may include:

bright field illumination microscopic examination up to 1000x magnification

stereomicroscopes and dissection microscopes

compound microscopes

phase contrast microscopes

inverted microscopes

Biological samples

Biological samples may include:

smears, impression smears, sections, squashes, films and whole mounts

a monolayer of cells in smears and films

fixed smears for demonstration of bacteria by the methylene blue and Gram staining techniques

blood films stained by a Romanowsky technique to clearly show differentiation of granulocytes

stained sections of animal tissues using regressive haematoxylin and eosin to differentiate cytoplasmic and nuclear detail

differentially stained monocotyledon and dicotyledon stem sections to demonstrate the structure of vascular bundles (xylem, phloem and cambium)

stained whole mounts of helminths

whole mounts, such as liver flukes, planaria and samples of animal faeces to demonstrate ova, cysts and larvae

pond water organisms

onion root tip squash

midstream sample of urine

Physical samples

Physical samples may include:

sand

asbestos fibres

coal samples

construction testing materials

geological specimens

Checking prepared samples

Checking prepared samples may include looking for:

clean and scratch-free microscope slides to reduce artefacts

preparation according to SOPs

a homogeneous suspension of sample

films and smears that have been fixed rapidly

thin films with a monolayer of cells

appropriate whole mounts for intact organisms

correct sample identification during and after processing

Sample characteristics

Sample characteristics are restricted to what can be viewed by bright light microscopy and may include:

shape and size of particles

presence of contamination

colour

consistency and variability

number of cells (e.g. cells in blood or other particulate samples, such as a yeast suspension or pollen grains)

type of cells, percentage of atypical cells, presence/absence of cells, size of cells, viable and non-viable cells and trajectory

presence of stained material, such as starch

colour/staining and morphology

motility

Calculations

Calculations may include:

dilutions

percentage viability

number of cells in original sample after dilution

calculation of cells/ml in a number of squares of a counting chamber

Hazards

Hazards may include:

micro-organisms and agents associated with soil, air, water, blood and blood products and human or animal tissue and fluids

chemicals and stains

sharps and broken glassware

aerosols

Safety practices and personal protective equipment

Safety practices and personal protective equipment may include:

use of MSDS

use of personal protective equipment, such as safety glasses, gloves and coveralls

use of biohazard containers and laminar flow cabinet

correct labelling of reagents and hazardous materials

handling and storing hazardous materials and equipment in accordance with labels, MSDS and manufacturer's instructions

ergonomic layout, correct illumination and organisation of workbench

regular cleaning and/or decontamination of equipment and work areas

Occupational health and safety (OHS) and environmental management requirements

OHS and environmental management requirements:

all operations must comply with enterprise OHS and environmental management requirements, which may be imposed through state/territory or federal legislation - these requirements must not be compromised at any time

all operations assume the potentially hazardous nature of samples and require standard precautions to be applied

where relevant, users should access and apply current industry understanding of infection control issued by the National Health and Medical Research Council (NHMRC) and State and Territory Departments of Health