Triple sugar iron agar (TSI) is a differential medium that contains lactose, sucrose, a small amount of glucose (dextrose), ferrous sulfate, and the pH indicator phenol red. It is used to differentiate enterics based on the ability to reduce sulfur and ferment carbohydrates.

Ferrous ammonium sulfate serves as the indicator, which turns the butt black in the presence of free hydrogen sulfide gas. Enteric organisms that are capable of fermenting glucose will produce acid (a yellow butt and a red slant), a positive hydrogen sulfide result.

Result Interpretation on Triple Sugar Iron (TSI) Agar

This content was developed by Houston Community College.

1. Pre-Assessment Activity. Begin by taking the Pre-Assessment Activity to determine your testing needs.
2. Practice and Review. Next it will be helpful for you to complete the practice quizzes in reading, writing or math.
3. Take the Assessment Test. First Pay Testing Fees.

Have met the minimum college readiness standard on SAT®, ACT, or a statewide high school test; Have successfully completed college-level English and math courses; Have enrolled in a Level-One certificate program (fewer than 43 semester credit hours);

You will need a score of 351 to pass, which, once again, means that you can safely miss between 1–3 questions.

2021 – 2022 Catalog Texas Success Initiative (TSI) Program

The TSI program is designed to promote the success of students in college by assessing students’ academic skills through a state approved examination called the TSIA2. All students in Texas public colleges are required to take the TSIA2 unless the student qualifies for a TSIA2 exemption.

Turbocharged Stratified Injection