MLS Clinical Procedures & Protocols 2

Question 1

A patient's blood culture bottle flags positive after 18 hours. What is the FIRST action the MLS should take?

Accepted Answer

Subculture to blood agar and report Gram stain to clinician

Answer

A positive blood culture flag requires immediate Gram stain and subculture, with results phoned to the clinician as a critical value.

Question 2

Which anticoagulant is used in the light blue (sodium citrate) tube and what is its primary application?

Accepted Answer

Sodium citrate; coagulation studies

Answer

Sodium citrate chelates calcium to prevent clotting and is the required anticoagulant for PT, aPTT, and other coagulation assays.

Question 3

A urine dipstick shows 2+ protein but the SSA (sulfosalicylic acid) test is negative. What is the most likely explanation?

Accepted Answer

The protein is Bence Jones protein or immunoglobulin light chains

Answer

Dipstick detects mainly albumin, while SSA detects all proteins including Bence Jones proteins; a negative SSA with positive dipstick suggests a false-positive dipstick reaction.

Question 4

During a venipuncture, blood stops flowing into the tube. Which corrective action should be attempted FIRST?

Accepted Answer

Slightly advance or withdraw the needle to reposition it

Answer

Slight needle repositioning is the first corrective step because the bevel may be against the vessel wall or the vein may have collapsed.

Question 5

Which specimen type is MOST appropriate for detecting anaerobic bacteria?

Accepted Answer

Deep wound tissue submitted in an anaerobic transport container

Answer

Anaerobes die rapidly on exposure to oxygen, so deep tissue submitted in sealed anaerobic transport is necessary for recovery.

(MLS) Medical Laboratory Scientist Practice Test

(MLS) Medical Laboratory Scientist Practice Test

MLS Clinical Procedures & Protocols 2