QUALITY ASSURANCE Quality Assurance of Reagents Supplies And

QUALITY ASSURANCE Quality Assurance of Reagents, Supplies, And Laboratory Water

• In order to produce high quality work, a laboratory requires a constant supply of good quality reagents, supplies and water • A deficiency of any of these can cause the most efficient laboratory either to come to a standstill or to provide substandard service 2

Choice and Evaluation of Reagents and Supplies • A selection of a brand of reagent for instrument system or laboratory tests is made after searching and gathering information concerning the reagent sensitivity, preparation, storage, and cost • Next, an evaluation of the selected material is performed in the laboratory, comparing the new reagent to the old • If the comparison is favorable, the new reagent is purchased 3

Choice and Evaluation of Reagents and Supplies • Before committing to purchase insists on performing a field trial of the reagent • Factors that should be considered in selecting and evaluating a new reagent or material supplies are: 1. Sensitivity 2. Stability and storage conditions 3. Vendor reputation 4. Delivery time 5. Cost 4

Laboratory Inventory Management • Effective inventory control involves setting up a system that has the following goals: • Simplify and reduce paperwork • Improve communication between the laboratory and the other hospital departments involved in purchasing, stocking, and paying for supplies • Manage inventory so that Shortages and overstocking should be avoided • Teaching laboratory employees better budgeting and materials management techniques 5

Inventory Control Program • Designing and implementing an inventory control program involves : • The identification of the needed supplies • Their rate of use • Periodic review and evaluation of the inventory and ordering process 6

Inventory Control Program • Conduct a survey to list all of supplies that the laboratory uses, the list should include: • The name of the item • A brief description • Approximate usage per month • Current vendor • Order unit amount • Current unit packing, that is per box, carton, or bag • Order or catalogue number • Priority of need • Assigning an item its relative importance • High priority: if needed constantly or cannot be done without • Medium priority: if needed occasionally • Low priority: if needed rarely 7

Inventory Control Program • The next step is to determine the order point, order quantity and lead time for the item • Order point: the sum of the minimum inventory plus the emergency supply • The level of inventory at which an order is generated • Lead Time: is the length of time between initiating an order and receiving it in the laboratory 8

Inventory Control Program • Controlling inventory involves the counting, storage and movement of supplies within the laboratory • A written record system of inventory levels and checks should be devised • Three types of record systems are suggested: 1. The periodic count • Strict inventory control is not required • Count of materials weekly or every two weeks, when count reaches the order point, an order is generated • Good for small to midsize Lab. 9

Inventory Control Program 2. The perpetual inventory record • Strict inventory control is required • Inventory is closed to lab. Personnel, one or two persons manage it • Good for larger lab. 3. The specialized inventory record • Used for slow-moving, infrequently ordered parts such as instrument spare parts • Parts are not ordered until inventory is used • Once the inventory system has been set up, it should be reviewed annually for updating 10

Reagents Prepared in the Lab. • Reagents, standards and controls prepared in the laboratory from stock chemicals should be: • Prepared using class A volumetric glassware and properly calibrated balances • To eliminate variation (batch to batch), preparation should be limited to one or two persons • Label each reagent, standard, and control with the following: • The name of the material • The procedure for which the material is to be used • Date of preparation • Date of expiration • Initials of the person who prepared it 11

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Laboratory Water • Reagent - grade water must be properly purified and periodically inspected for: • Electrical resistivity • Resistivity (R) of water is the measurement of electrical resistance and is the inverse of electrical conductivity (C) • R and C are directly related to the number of inorganic ions and conduction particles in the water • The greater the ionic concentration, the greater the electrical conductivity and the less the electrical resistance • Measurements are made using a resistivity or conductivity meter • Soluble silica concentration • measured by a chemical reaction between silicate and molybdate ions to form a blue complex 13

Laboratory Water • Desired p. H • The p. H is measured with p. H meter • Bacterial contamination • The microbiological content of the water is defined as the number of colony - forming units per milliliter of water • Three recommended methods: • Pour plate (1 ml of water) • membrane filtration • or calibrated loop for sampling (0. 01 ml) • If organic free water is desired , soluble organic materials can be removed using charcoal filter 14

Laboratory Water • Purification of water can be achieved through 3 methods: • Distillation • Deionization • Reverse osmosis • Additional purity is obtained with charcoal filtration. Membrane capacitive deionization 15

Water Grades According to Purity • Type I water: • The highest level of purity, • used for: • tissue and cell culture methods • special and critical analytical chemical analysis • and in preparation of standard solutions • Type II water: • Used for most routine quantitative clinical laboratory methods • It should be stored for short periods of time before use, to prevent change in resistivity and bacterial growth 16

Water Grades According to Purity • Type III water: • The least pure • Suitable for most qualitative procedures including: • Urine analysis • parsitology • and histology • Suitable for glassware washing • Stored in containers that protect it form contamination 17

Three of Clinical Laboratory Water 18