An Overview of Subjective Global Assessment

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The Subjective Global Assessment (SGA) is a type of clinical tool doctors use to determine a person's overall state of health. It is most often used when assessing nutritional status in patients with kidney problems like end-stage renal disease or chronic renal insufficiency. The method is also useful when evaluating patients at risk for malnutrition.

Purpose of Test

If you are malnourished it is very important that your doctor addresses the underlying cause. When your body is not getting adequate nutrition, your immune system can't function as well. This puts you at risk for bacterial and viral infections. If you're malnourished for a long time, you may be more likely to develop weak bones (osteoporosis) or complications from specific vitamin deficiencies (like blood clotting disorders).

If you are recovering from an illness, injury, or surgery, being malnourished will make it harder for your body to heal and increase your risk for complications.

When your body is deficient in energy and key vitamins, it will take longer for you to heal from even relatively mild illnesses like colds or injuries like cuts.

Conditions That Cause Malnourishment

The SGA can help doctors figure out why a person has become malnourished. Some conditions, such as HIV, AIDS, and cancer, cause the body to use a lot more energy. This can lead to severe weight loss and muscle wasting—a condition called cachexia. Muscle wasting occurs naturally as a person ages (sarcopenia) and doctors need to distinguish between normal changes to a person's muscle mass and those caused by an infection, inflammation, or other potentially serious health problem.

Malnutrition can also occur for other reasons—either because a person does not get enough to eat or their body is unable to absorb nutrition from what they eat. People who are very ill may have a lack of appetite or side effects from medications or treatments that make it difficult for them to eat.

For example, patients receiving chemotherapy may experience nausea and vomiting, people who are pregnant may experience a severe form of morning sickness called hyperemesis gravidarum, and people with depression may not feel like eating (due to the symptoms of their depression, the medications used to treat it, or both).

People who have eating disorders such as anorexia nervosa or bulimia nervosa are also at risk for malnourishment.

People with these conditions may only eat a limit variety of foods in very small amounts, severely restrict everything they eat, and/or purge what they eat and drink. Cycles of binging and purging also put people at serious risk of vitamin and electrolyte imbalances.

Certain medical disorders put a person at risk for malnourishment because they impact the body's ability to absorb nutrition from the foods they eat. Malabsorption Syndrome can occur in a number of conditions, such as:

  • gastrointestinal diseases such as Crohn's or ulcerative colitis
  • after weight-loss surgery
  • cystic fibrosis
  • celiac disease as well as various food allergies or intolerances
  • some medications, including over-the-counter laxatives
  • pancreatic insufficiency
  • cancer
  • kidney disease
  • liver disease
  • conditions or infections that cause prolonged diarrhea
  • certain genetic disorders or metabolic conditions

Socioeconomic Conditions

Malnourishment can also be brought about due to socioeconomic conditions. If a person is living in poverty, is elderly, or is disabled, they may not have regular access to nutritious food. In these cases, a medical professional will usually seek resources from their social services colleagues, government, or community-based programs.

Risks and Contraindications

Your doctor performs the SGA by looking at your medical record, asking you questions, and performing an exam. Depending on the reason for your visit, there may be other information you need to know (such as if you are having a test or procedure on the same day).

The medical staff may ask you about any medications or supplements you are taking. They may ask you to bring the bottle with you so they can check the dose and the name of the drug you have been prescribed with what they have in your medical record. You may be asked about any over-the-counter medications you take as well as if you eat or drink foods that may interact, such as alcohol or grapefruit.

Before the Test

Timing

You will not need to make an appointment for this evaluation. Doctors typically use SGA while taking your medical history and performing a physical exam.

Location

SGA is used by a variety of medical professionals in different settings, including:

  • routine doctor's office visits (like your annual wellness exam)
  • emergency room encounters
  • pre-operation appointments or follow-up visits after a procedure
  • during a hospital admission

What to Wear

You may be asked to change out of your street clothes and into a gown, especially if you will be undergoing certain medical tests, procedures, or surgery. Your doctor may allow you to stay in your regular clothes but may need you to give permission for them to examine you—such as by lifting your shirt so they can apply a stethoscope or feel your abdomen during an exam.

Food and Drink

You do not need to avoid eating or drinking for the SGA, but you may receive instructions specific to another test or procedure you will be having the same day. You will need to carefully follow these instructions, especially if you are having surgery.

The SGA is used to evaluate your nutritional status, so your doctor may ask you questions about your diet. They may also ask if you have any problems with eating or drinking, such as trouble swallowing or a loss of appetite.

They may also ask you questions about whether you have enough to eat or have trouble paying for groceries.

Cost and Health Insurance

SGA is performed as part of another exam. When it is done at your yearly checkup, for example, it may be covered completely by your insurance. When it is done as part of an evaluation in the emergency room, you may have a copay for the cost of the visit if you have insurance, or you may need to pay coinsurance.

If you don't have health insurance, the cost of a doctor's visit, emergency room visit, surgery, or hospital stay will vary widely depending on where you live and the length of the stay. If you have questions about your bill or aren't able to pay, you can call the hospital's billing department.

What to Bring

You do not need to bring anything specific for the SGA evaluation, but depending on the reason for your visit, your doctor may ask you to bring any medications you take or medical devices you use. If you are having a procedure or surgery that requires sedation or anesthesia, you will need someone to come with you who can drive you home after.

Other Considerations

The SGA evaluation may be used by more than one member of your healthcare team. You may be asked the same questions each time you see a new doctor or even each time you see your regular doctor, which helps them track your progress. Monitoring any changes in your status is especially important if you have a chronic illness, are recovering from surgery or an injury, or have another medical problem that puts your health at risk.

During the Test

Your doctor or another healthcare professional involved in your treatment will ask you a series of questions about your health. They may also be able to get some of the information they need, especially changes that have occurred over time, from looking at your medical record.

Pre-Test

You may have your vital signs checked by a nurse before you talk to your doctor, including your blood pressure, heart rate, and breathing. The nurse may ask you some of the same questions as your doctor and may update other information in your medical records, such as your list of medications, insurance information, or emergency contact.

During the Test

Your doctor may ask you questions related to:

  • how much you weigh
  • if you have recently gained or lost weight
  • what type of physical activity you normally do and if you exercise regularly
  • how much fluid you drink each day
  • how much you eat each day and what types of foods you eat
  • any medications, supplements, or vitamins you take
  • any over-the-counter medications (OTC) you take
  • if you smoke cigarettes, drink alcohol, or regularly consume foods or beverages that may interact with certain medications
  • if you take any other drugs such as marijuana
  • if you have any gastrointestinal symptoms (throwing up, bowel changes, stomach pain)
  • how often you go to the bathroom
  • if you have any pain or swelling
  • if you have trouble doing things like walking up stairs, doing chores around the house, bathing and dressing, or other activities of daily living
  • if you are able to work
  • if you have enough food to eat and if you have trouble paying for groceries
  • if you have any health problems that are longterm (chronic) or new

They may also perform a physical exam, including weighing you on a scale, calculating your body mass index (BMI), looking at your mouth and teeth, using tools to look at your eyes and in your ears, and measuring your waist, chest, arms, or another part of your body to assess how much muscle mass and fat mass you have.

In addition, the doctor may have you grip objects or testing your muscle strength, ask you to perform tasks like getting up from a chair, stepping up on a step, or bending down to touch your toes, and check your feet, hands, face, and abdomen for signs of swelling.

Post-Test

Depending on the reason for your visit you will be given specific instructions about following up. This may include picking up a prescription at the pharmacy, making an appointment to come back, visiting another type of doctor or specialists, getting scheduled for a test or procedure, or being admitted to the hospital.

After the Test

Follow any instructions your doctor provides carefully. Ask questions if you are not sure what is expected of you or are not clear on what to do next.

Managing Side Effects

The SGA doesn't have any specific side effects.

Interpreting Results

Follow-Up

Since the SGA is used to assess your nutritional status, if your doctor feels you are at risk for malnourishment, you may be referred to another type of medical professional who can help, including nutritionists, dieticians, gastroenterologists, and endocrinologists.

If you have an underlying medical condition that is affecting your nutrition, such as cancer, an eating disorder, or an autoimmune disease, your doctor may refer you to a specialist who handles the type of condition you have.

Treating the underlying condition is often the first step to improving your nutritional status and preventing malnourishment.

Other Considerations

If you are not adequately nourished because you don't have regular access to enough food or have trouble affording groceries, your doctor may refer you to a social worker who can help you access government services, food pantries, or other forms of assistance in your community.

If you are unable to work due to injury or illness, you may be eligible for disability benefits or food assistance programs that can help.

A Word From Verywell

The Subjective Global Assessment (SGA) is a type of clinical tool doctors use to determine a person's overall state of health. It is most often used when assessing nutritional status in patients with kidney problems like end-stage renal disease or chronic renal insufficiency. The method is also useful when evaluating patients at risk for malnutrition due to other conditions such as anorexia nervosa, cancer, HIV/AIDS, and those who are living in poverty, elderly, or disabled.

The consequences of malnourishment can be serious. Early recognition and prevention are important. Diagnosing the underlying medical disease or addressing any socioeconomic factors and providing resources is integral to a positive outcome regardless of the cause.

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Article Sources

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  • Detsky A, Mclaughlin, Baker J, et al. What is subjective global assessment of nutritional status? Journal of Parenteral and Enteral Nutrition. 1987;11(1):8-13. DOI:10.1177/014860718701100108

  • Fontes D, Generoso S, Toulson Davisson Correia M. Subjective global assessment: A reliable nutritional assessment tool to predict outcomes in critically ill patients. Clinical Nutrition. 2014;33(2):291-295. DOI:10.1016/j.clnu.2013.05.004

  • Steiber A, Kalantar-Zadeh K, Secker D, McCarthy M, Sehgal A, McCann L. Subjective Global Assessment in chronic kidney disease: A review. Journal of Renal Nutrition. 2004;14(4):191-200. DOI:10.1053/j.jrn.2004.08.004