Preparing for the GPhC pharmaceutical calculations assessment 

Introduction

Foundation trainee pharmacists frequently report challenges in understanding and performing pharmaceutical calculations. These calculations are assessed within part 1 of the General Pharmaceutical Council (GPhC) registration assessment. The pass score for the most recent exam sitting was 25 marks out of a possible 40 (62.5%)^​1​ and to achieve this foundation trainees need to prepare well and use their time effectively. 

Common avoidable errors include poor time management/allocation during the exam, inadequate preparation and practice and inadequate knowledge of unit conversion.

As you prepare for part 1 of the GPhC assessment, there are several important points to keep in mind: 

• Knowing the correct topics to revise; 
• The importance of carefully planning your revision to ensure that you cover all topics and can track your progress. 
• The need to master units and conversions; 
• Knowing concentrations and their different permutations, 
• Practising sample questions and past papers and being able to handle a wide range of question types. 

This article provides eight tips on how best to prepare for part 1 of the GPhC registration assessment. Articles covering individual calculation topics in more detail are available from The Pharmaceutical Journal and listed at the bottom of the page.

Tip 1: Familiarise yourself with the GPhC assessment framework 

Part 1 of the GPhC exam focuses on the following learning outcome from section 10.2.3 of the assessment framework: 

It is a highly weighted learning outcome and failure to achieve the passing score for part 1 of the exam will prevent you from passing the GPhC assessment.

The topics covered in the exam are shown in Box 1.

There will be 40 questions in the exam and each of these topics will be examined at least once. It is important that you can tackle all aspects of pharmaceutical calculations and prepare equally across all topics. You will have two hours to complete part 1, which equates to an average of three minutes per question; however, it is important to be aware that some questions will be quicker to answer than others. Rather than allocating three minutes of time to each question, you will need to look for opportunities to bank time where you encounter questions that you can manage comfortably to use for questions that will take you longer.

Tip 2: Make a revision plan and use your time effectively

While this article focuses on part 1 of the exam, you will need to ensure you revise strategically and keep in mind that you will need to prepare for both parts of the exam. For guidance on how to prepare for part 2 of the exam see the article ‘Preparing for the GPhC registration exams: six steps to help you effectively plan your revision’. It is wise to focus initially on the areas where you are less confident while allocating sufficient revision time for part 2 of the exam as well. 

It will be down to you to come up with a plan that works for you but an example of a simple revision timetable is below. 

Reproduced with kind permission from focuspreg.com

Tip 3: Read the feedback from previous exam sittings

The GPhC publishes feedback after each exam sitting and this provides invaluable information on common errors made by previous cohorts. Read through this feedback and use it as a guide when you begin to plan your revision and allocate time for different topics. Links to feedback from recent exams cohorts are below.

• Feedback from the June 2024 registration assessment sitting; 
• Feedback from the November 2023 registration assessment sitting;
• Feedback from the June 2023 registration assessment sitting.

Tip 4: Ensure you fully understand the basics

At this stage of your pharmacist education and training, you should be familiar with the common metric units of weight, volume and time and be competent in converting between these units. Although this may sound obvious, some foundation trainees struggle with conversion of units especially between grams, micrograms and nanograms. Marks can be lost owing to avoidable mistakes arising from incorrect conversion of units. It is important to be fully secure in your knowledge of units and conversions before you begin to revise specific calculation topics in depth. Table 2 below shows some of the metric units that are commonly used in pharmacy practice. 

Trainee pharmacists should also know the various forms of expressing concentration and can correctly convert from one form of concentration to another. The common concentrations units in pharmacy practice are shown in Table 3. This list is not exhaustive.

The full list of units that you are likely to encounter in the GPhC exam can be found in the current GPhC assessment framework^​2​. The GPhC feedback also reveals that often, trainee pharmacists did not follow specific rounding instructions or failed to apply knowledge of the practicalities of providing a specific dose (e.g. accounting for graduation markings on a pre-filled syringe or optimising for ease of administration)^​3​.

Tip 5: Attempt all the sample questions provided on the GPhC website

The GPhC provide access to a bank of sample questions that you can work through as part of your preparation. The questions use the same online system as the exam itself meaning that you can familiarise yourself with how it works and know what to expect on the day. 

Other banks of sample revision questions are available from a number of sources, including Pharmacy Knowledge ONtrack.

Tip 6: Be prepared for questions to have multiple steps 

Questions are often designed to test multiple competency outcomes. For example, a single calculation question may test your knowledge and competency in converting units, understanding the various expressions of concentrations, and correctly applying rounding rules while requiring you to apply clinical knowledge to the question. A mistake made in any of these steps will result in an incorrect answer. 

Tip 7: Consider the context of the question

While part 1 of the assessment is primarily focus on pharmacy calculations, questions are scenario based and you will still need to consider the ‘real-world’ context. For example, a dose calculation may be performed correctly but require you to factor in practical considerations such as the amount of product contained in a pack, how long a product can be stored or other details associated with a specific dose or route of administration.

Tip 8: Use high-quality resources and access the support that is available to you

There is a wealth of information available but the quality of materials and relevancy to the GPhC assessment outcomes will vary. Your university will also be able to provide support and suggestions. Organisations including the RPS and third party providers also offer addition revision support. 

Next steps

The following articles from The Pharmaceutical Journal provide greater depth on specific calculation topics and can be incorporated into your revision:

GPhC exam part 1

• Medication maths: how to solve dose and dosage calculations (video);
• Medication maths: how to solve infusion calculations (video);
• Medication maths: quantities to supply and using provided formulae calculations (video);
• Medication maths: how to solve pharmacy calculations – concentrations, dilutions, and health economics (video);
• ‘Medication maths: estimations of kidney function‘;

GPhC exam part 2

• ‘Preparing for the GPhC registration exams: six steps to help you effectively plan your revision‘;
• ‘Preparing for the GPhC registration exams: how to approach learning outcomes relating to professional practice‘;
• ‘Preparing for the GPhC registration exams: how to approach learning outcomes relating to professional practice‘.