Reasons, Preparations & Procedure of Chemistry Screen Test

Submitted on March 27, 2012

Chemistry Screen Test

A chemistry screen is a blood test. Blood is composed of many substances, and a chemistry screen can help to identify the level of these substances. There could be many reasons why a chemistry screen needs to be done.

Reasons Why It is Conducted

  • It could be done as a part of a routine health checkup.
  • It may be asked for before a surgical procedure.
  • It may be used to analyze the effect and progress of a treatment.
  • It may be used to measure the amount of blood glucose in an individual.
  • The results may be used to recommend changes in lifestyle to help with weight loss.

The list of reasons why this test needs to be done can be endless due to the large amount of useful information it provides.

There are different types of chemistry screens. Some of them are used to profile all the constituents of the blood, and some are specifically targeted at just a few. Tests such as the SMA-20, chem-20, or SMAC-20 analyze almost 20 substances in the blood. Other tests such as the SMA-6, SMA-7, and SMA-12 are used to identify 6, 7, or 12 substances in the blood based on the need. The SMA-20 is typically considered as a complete blood test.

Preparation Required

The test requires some amount of preparation on the part of the individual. The most common instructions that are given are as follows:

  • Not to eat or drink anything except water for at least 12 hours before the test. This is generally asked when the fasting blood sugar needs to be measured.
  • Not to consume any form of alcohol before the test.
  • Not eat any food that is high in fat the night before the test.

It is important to follow these instructions, as not following them may cause the results of the test to vary.

How is it done?

The test involves collection a sample of blood from the vein in the arm. The individual being tested can feel a small pinch when the needle is inserted into the vein. Once the blood sample has been collected, a small cotton ball dipped in an antiseptic spirit is pressed at the location from where the blood was collected. The patient may be asked to retain this till the blood flow stops. The results of this test are normally available within two days.

There are many parameters that are measured by this test. Lets us look into two of them.

The carbon dioxide chemistry gives an idea of the amount of carbon dioxide contained in the blood. This helps a doctor to identify the reason for breathing problems and other lung related conditions.

Blood glucose chemistry is also called as the blood glucose test. It helps to identify the content of glucose in the blood. The results of a fasting blood sugar can help a doctor to know if the patient is diabetic or if the levels of sugar in the blood are extremely low.

A chemistry screen has very few risks associated with it. It is important to inform the doctor about any medication that the patient may be using before taking the test.