CTBS Processing Techniques 3

Question 1

Which factor most significantly affects the residual moisture content of a lyophilized bone allograft?

Accepted Answer

The duration and temperature of the secondary drying phase

Answer

The secondary drying (desorption) phase of lyophilization, which removes bound water, has the greatest effect on final residual moisture content of the product.

Question 2

When processing soft tissue allografts (e.g., tendons, ligaments), what is the primary function of low-dose gamma irradiation (< 20 kGy)?

Accepted Answer

To reduce bioburden without significantly compromising mechanical properties

Answer

Low-dose gamma irradiation is used to reduce microbial bioburden while minimizing radiation-induced damage to the collagen structure and mechanical integrity of soft tissue allografts.

Question 3

What is the purpose of adding a radioprotectant such as ascorbic acid or mannitol during irradiation of soft tissue allografts?

Accepted Answer

To scavenge free radicals generated by radiation and reduce collagen damage

Answer

Radioprotectants like ascorbic acid and mannitol are free radical scavengers that neutralize reactive oxygen species produced by radiation, thereby reducing radiation-induced collagen degradation.

Question 4

During aseptic tissue processing, which environmental classification is required for the critical zone where tissue is exposed?

Accepted Answer

ISO Class 5 (Class 100)

Answer

ISO Class 5 (equivalent to Class 100) clean room conditions are required in the critical zone where tissue is directly exposed during aseptic processing to minimize particulate and microbial contamination.

Question 5

What processing step is used to remove lipids from bone allografts, and why is it performed?

Accepted Answer

Defatting with organic solvents such as chloroform-methanol; improves handling and reduces inflammatory response

Answer

Defatting with organic solvents like chloroform-methanol removes bone marrow fat, which improves handling characteristics, reduces rancidity during storage, and decreases inflammatory response after implantation.

(CTBS) Certified Tissue Bank Specialist Practice Test

(CTBS) Certified Tissue Bank Specialist Practice Test

CTBS Processing Techniques 3