The CALL Score Calculator is a clinical decision support tool developed to assist in predicting the potential outcomes of patients diagnosed with COVID-19. The acronym “CALL” stands for four key medical factors that influence the progression of the disease: Comorbidities, Age, Lymphocyte count, and LDH (Lactate Dehydrogenase) levels. By evaluating these parameters, the calculator generates a numerical score that helps estimate the likelihood of a patient's condition worsening.
This scoring system was created based on data collected from patients during the COVID-19 pandemic and is especially useful in hospital settings or for individuals under close medical supervision. The total score places patients into one of three risk classes:
The CALL Score Calculator is easy to use and requires just a few inputs related to the patient’s age, known health conditions, recent blood test results (specifically lymphocyte count and LDH levels). Once entered, the calculator provides an immediate score and corresponding risk level.
The CALL Score Calculator is intended for use by healthcare professionals, caregivers, and individuals who want to better understand the potential risk of COVID-19 progression in themselves or someone they are caring for. It is especially useful for patients who have already tested positive for COVID-19 and are in the early stages of the illness.
This tool can also benefit:
However, it is important to note that the calculator should not be used by individuals to self-diagnose or decide on treatment without medical guidance. The CALL Score is a supportive tool and should be used as part of a broader clinical evaluation by a qualified healthcare provider.
If you or someone you know has COVID-19 symptoms or test results and is concerned about worsening health, it’s always best to contact a medical professional, even if the score appears low.
Using the CALL Score Calculator is quick and straightforward. Just follow the four steps below by selecting the option that best describes your situation in each category. Once all selections are made, click the "Calculate" button to receive your total score, risk class, and predicted risk level.
Comorbidities refer to pre-existing medical conditions that can increase the severity of COVID-19. These may include:
If you have at least one of the conditions listed above, select “Yes.” If not, choose “No.” Having comorbidities will increase your CALL score, indicating a higher risk level.
Age is a significant predictor of COVID-19 outcomes. The calculator groups users into two categories:
Simply choose the option that reflects your current age. Older individuals tend to be more vulnerable to complications and may receive a higher score.
Lymphopenia is a condition where the level of lymphocytes (a type of white blood cell) in the blood is lower than normal. It indicates a weakened immune system response.
- If your lymphocyte count is greater than 1000/mm³, select “No lymphopenia.”
- If your lymphocyte count is 1000/mm³ or less, select “Lymphopenia.”
Low lymphocyte counts are associated with a higher risk of severe COVID-19, so this input directly affects your total score.
LDH is an enzyme found in almost all body tissues. Higher LDH levels can indicate tissue damage or stress and are often elevated in severe COVID-19 cases.
Choose your LDH level from the following ranges:
The higher your LDH, the more points you receive in this section, increasing your overall risk classification.
Once all selections are made, press the “Calculate” button. Your result will show a total score, a class (A, B, or C), and a risk level (Low, Intermediate, or High).
After you enter your information and click the "Calculate" button, the CALL Score Calculator will display three results:
The total score is the sum of the points assigned based on your answers to the four categories: Comorbidities, Age, Lymphocyte Count, and LDH Levels. Each answer has a numeric value, and the higher the total score, the greater the risk of your COVID-19 condition becoming more severe.
The score helps doctors and patients estimate the level of care that might be needed. While a lower score generally suggests a mild case, a higher score indicates the need for closer monitoring and possibly more aggressive treatment.
Once your score is calculated, it falls into one of three classes that represent your risk category:
The CALL Score Calculator divides patients into three main risk categories based on their total score: Low Risk, Intermediate Risk, and High Risk. These categories help estimate how likely it is that a patient's COVID-19 condition will worsen over time. Understanding what each category means can help patients and caregivers make informed decisions about monitoring and seeking medical attention.
Patients in this category are considered to have a low chance of experiencing severe complications from COVID-19. The risk of disease progression is estimated to be less than 10%. Most individuals in this group can recover safely at home with supportive care such as rest, hydration, and fever management.
However, it's still important to monitor symptoms closely and contact a healthcare provider if any new or worsening signs appear, such as difficulty breathing, persistent chest pain, or confusion.
This category represents a moderate risk of condition worsening, with an estimated progression rate of 10% to 40%. Patients may require closer observation, additional tests, or medical support—especially if they start to show signs of respiratory stress.
Healthcare providers may recommend more frequent check-ins, either remotely or in person. Hospitalization is not always needed at this stage but may become necessary if the patient's condition changes.
A high CALL score indicates a significant likelihood—50% or more—of developing severe COVID-19 complications. This group includes patients who may need immediate medical attention, advanced monitoring, or even intensive care.
If you or someone you know falls into this category, it's critical to alert a healthcare professional right away. Early intervention can make a substantial difference in outcomes for high-risk individuals.
CALL stands for the four factors used in the calculator: Comorbidities, Age, Lymphocyte count, and LDH (Lactate Dehydrogenase) levels. These factors help predict the risk of COVID-19 progression in a patient.
Yes. To get an accurate score, you’ll need recent blood test results for your lymphocyte count and LDH level. These values are usually available from a standard blood panel.
Yes, but it is intended to be used with the guidance of a healthcare provider. While anyone can input values and get a result, the interpretation and medical decisions should be made by a professional.
If the calculator places you in the high-risk category (Class C), you should contact a healthcare provider immediately. This may indicate the need for hospitalization or close monitoring. Do not rely solely on the score—seek medical advice right away.
No. The CALL Score is a predictive tool, not a diagnostic test. It helps estimate the risk of worsening symptoms but does not confirm or rule out any medical condition.
The CALL Score was developed based on early pandemic data and may not fully reflect the impact of newer variants or changing treatment protocols. Always consult with your doctor for the most up-to-date guidance.
Yes, but the calculator does not take vaccination status into account. Vaccination may lower the risk of severe illness, so the results should be interpreted in the context of your overall health and medical history.
No. The score is a helpful guide but should not be the only factor in deciding whether to seek hospital care. If you are experiencing symptoms like shortness of breath, chest pain, or confusion, you should seek medical help immediately—regardless of your score.
The CALL Score Calculator is intended for informational and educational purposes only. It is designed to help estimate the risk of COVID-19 progression based on selected clinical factors, but it does not provide a medical diagnosis or treatment recommendation.
This tool should not be used as a substitute for professional medical advice, diagnosis, or care. Always consult a qualified healthcare provider regarding any medical condition or concern. Never delay seeking medical attention based on the results of this calculator.
While the calculator is based on published research and clinical data, individual patient outcomes may vary, and the accuracy of the score may be affected by missing or inaccurate input data. The tool does not account for all possible medical variables, including vaccination status, emerging variants, or changes in treatment protocols.
By using this calculator, you acknowledge and agree that the creators of the tool are not responsible for any decisions made based on its output. For emergency situations, call your local emergency number or go to the nearest hospital.