Quality assurance is a management or oversight function, it deals with setting policy and running an administrative system of management control that cover planning, implementation and review of data collection activities and the use of data in decision making.
Where as Quality Control is a technical function that includes all the scientific precautions, such as calibrations and duplications that are needed to acquire data of known and adequate quality.

The easiest way to categorize these two is to say that quality assurance deals with verification while quality control deals with validation. QA looks to prevent quality problems through planned and systematic activities. Their main goal is to improve development and test processes so that defects do not arise when the product is being developed. QC uses activities to achieve and maintain product quality, process, and service. Their main goal is to identify defects after a product is developed and before it's released.

Two terms that have many interpretations because of the multiple definitions for the words assurance and control. One definition of quality assurance is: all the planned and systematic activities implemented within the quality system that can be demonstrated to provide confidence that a product or service will fulfill requirements for quality. One definition for quality control is: the operational techniques and activities used to fulfill requirements for quality. Often, however, “quality assurance” and “quality control” are used interchangeably, referring to the actions performed to ensure the quality of a product, service or process.

http://asq.org/learn-about-quality/quality-assurance-quality-control/overview/overview.html

Quality Assurance: ensures that the approaches, techniques, methods and processes are designed for the projects are implemented correctly. Quality assurance activities monitor and verify that the processes used to manage and create the deliverables.
Quality Control: ensures that the approaches, techniques, methods and processes are designed in the project are following correctly. Quality Control activities monitor and verify that the project deliverables meet the defined quality standards.

The QA and QC both are the part of Quality Management system .QMS takes comprehensive approach affecting the company's processes ensuring the safety and efficiency. QA is process oriented or procedure oriented as it focused on methods how to prevent the defects in the process while QC focus on the identification of the defects hence it is product oriented. QC follows steps to check the end product against quality standards. QA main goal is to improve development and tests processes so that the defects do not arises when product is being developed where as QC identify defect in the finished product before it is released. . Hence, QA is a proactive quality process and QC is a reactive process. QC may be conducted at several steps through out production as well as at the end as final QC inspection so to catch non conforming product before they reach the customer. QA tends to be applied more towards engineering rather than manufacturing required more formal education and training as compare to QC.

QA or Quality Assurance makes sure that the project is meeting all industry regulations. For example if you want to set new storage conditions for one of your devices, you consult the quality assurance specialist to make sure that this is 1) meeting industry regulations and 2) all labels and customer letter and product inserts are updated to include the new storage conditions. They are in charge of properly communicating these so that it meets any labeling requirements.

QE or Quality Engineering is more in charge of the process to validate and should consult with QA to make sure the outputs meet standards. For example, to set those new storage conditions the QE would have to do verifications and validations to support that the new storage conditions are adequate for the product.

Quality assurance is a set of different activities for ensuring the quality in the processes by which products are developed. It aims at preventing defects with a focus on the process, which is used to make the product. It is a proactive quality process. The main goal of QA is the improvement of the development and the testing processes. It establishes a good quality management system and the assessment of its adequacy. It is important for the prevention of quality problems through planned and systematic activities including documentation. Everyone on the team involved in developing the product is responsible for quality assurance. Verification is an example of QA.

Quality control is a set of activities for ensuring the quality of products. The activities focus on identifying defects in the actual products produced. It aims to identify and corrects defects in the final product. Unlike quality assurance, quality control is a reactive process. The main goal of QC is to identify defects after a product is developed and before it's released. Quality control is usually the responsibility of a specific team that tests the product for defects. Validation and software testing are examples of QC.

QA/QC is the combination of quality assurance, the process or set of processes used to measure and assure the quality of a product, and quality control, the process of ensuring products and services meet consumer expectations.

Quality assurance is process oriented and focuses on defect prevention, while quality control is product oriented and focuses on defect identification.

Quality Assurance (QA) is defined as if the project is equipped to handle the standards. It is a process oriented and focusses on defect prevention. QA is a set of activities for ensuring quality in the processes by which the products are developed. It aims to prevent defects with a focus on the process used to make the product. It is a proactive quality process. Everyone on the team is responsible for the quality assurance. Verification is an example of the quality assurance. Quality assurance is a process oriented.
Quality Control (QC) is defined if the project complying with the standards. It is product oriented and focusses on defect identification. Quality control is a set of activities which ensures the quality of the product. The activities focus on identifying defects in the actual products that are produced. Qc aims to identify and correct the defects in the finished products. So, it is a reactive process. The main goal of quality control is to identify defects after a product is developed and before its released. Quality control is usually responsible of a specific team that tests the product for defects. Validation is an example of Quality control. Quality control is a product oriented.

The primary difference between quality control (QC) and quality assurance (QA) is that QA correlates the industry's standards to the project at hand, whereas QC ensures that the standards are being met as a project proceeds. From an industry perspective, QC is more engaged with real time testing while QA works more with documentation and compliance with protocol. The company I work for is a project-based clinical research organization that manufactures autogeneic and allogeneic cell-based products for patient infusion. Since the product we work with is considered to be high risk (ISO 5 cleanroom standards), it requires QC to acquire daily samples of cell cultures for sterility analysis as they are currently being processed. At the same time, it is the role of QA to ensure that the batch record of the process was completed as per standard operating procedures (SOPs) and that all supporting documentation was fulfilled. For a company such as my own, QC essentially regulates the lab work and QA regulates all paperwork and electronic documentation.

According to lecture, there are 3 major processes that fall under quality control management: QC, QA, and quality planning. How does quality planning affect the QC and QA processes? The PMBOK Guidebook defines quality as "the degree to which a set of inherent characteristics fulfills requirements". Is it more efficient to determine FDA requirements prior to or after initiating a project? The PMBOK guide also covers quality-related topics such as quality metrics, quality audits, quality function deployment, etc. How do each of these contribute to the overall integrity of a project?

I'll add to what's been said above. People who work QA usually work with the people who are writing SOPs, change controls, etc. They're in the office making sure that all of the paper work and paper trail are correct and follow regulation. They catch any issues and send it back for revision. QC people are usually on the floor, checking machinery and the production area. They're familiar with the process and check to see whether things are they way they should be. If they aren't, they bring it up and ensure that CAPAs/Quality Notifications are written so that someone will address the issue(s).

Both quality assurance and quality control ensure the safety. Quality Assurance focus on the planning process and how closely the project is following to prevent any risk from arising . Quality Assurance verifies if everything is as plan. Quality control is the validation it is where the the product is deemed to pass or fail after looking at the result of the test done on the product. If the product fail, quality must find and fix the problem. This is the inspection process on the product.

The QA and QC both are embedded in Quality Management system. While QA focuses on defect prevention, QC deals with identification of those defects before hand.

QA&QC both are different from each other and required as part of quality management … QA is process focused while QC is end product focused. Quality Control is inspecting something( a product or a service) to ensure that it is working fine. QC Confirms that the standards that are defined during the QA process are followed while developing the product. Quality Control is a procedure or set of procedures intended to ensure that a manufactured product or performed service adheres to a defined set of quality or meets the requirement of the client or customer.