CCMA Laboratory Procedures 5

Question 1

A medical assistant performs a venipuncture on a patient with a mastectomy on the right side and an IV infusing in the left forearm. The physician insists the draw cannot be delayed. What is the MOST appropriate action?

Accepted Answer

Draw below the IV site on the left arm after the IV has been turned off for at least 2 minutes, and document the situation

Answer

When one arm is contraindicated (post-mastectomy risk of lymphedema and specimen contamination) and the other has an IV, the accepted procedure is to have the nurse stop the IV for at least 2 minutes, apply the tourniquet BELOW the IV site, draw from a vein distal to the IV, and document that the specimen was drawn distal to an IV. Drawing above (proximal to) the IV risks dilution and analyte contamination. Medical assistants may not draw from IV lines, and a mastectomy side is avoided regardless of how long ago the surgery occurred unless the provider specifically authorizes it.

Question 2

A CCMA collects a lavender, a light blue, and a red-top tube during a single draw, but fills the light blue (citrate) tube only halfway before the vein collapses. The coagulation test ordered is a PT/INR. What is the consequence of submitting this tube?

Accepted Answer

The result will be falsely prolonged because the excess citrate-to-plasma ratio binds additional calcium

Answer

Sodium citrate tubes require a strict 9:1 blood-to-anticoagulant ratio. An underfilled tube leaves excess citrate relative to plasma; the surplus citrate binds calcium added during testing, artificially delaying clot formation and falsely prolonging the PT/INR. Most laboratories reject citrate tubes filled below approximately 90% for this reason. Gentle inversion 3–4 times is correct handling and does not cause prolongation.

Question 3

While performing a CLIA-waived rapid strep test, the MA notices the internal control line fails to appear, though the test line is clearly positive. According to quality control principles, what must the MA do?

Accepted Answer

Invalidate the test, document the QC failure, repeat with a new kit or lot, and withhold reporting any result

Answer

A failed internal (procedural) control invalidates the entire test regardless of what the test line shows — the control failure means the reagents or procedure cannot be trusted, so even a strong-looking positive is unreportable. The correct sequence is to invalidate, document the failure in the QC log, and repeat the test with a new device (and a new lot if the problem recurs). Running external controls afterward cannot retroactively validate an individual failed device.

Question 4

A provider orders a blood culture, a lavender-top CBC, a green-top chemistry panel, and a light blue coagulation study. Midway through the draw, the MA realizes she filled the green top immediately after the blood culture bottles. What is the primary risk created by this error?

Accepted Answer

The light blue tube, drawn after the green top, may show falsely prolonged coagulation results due to heparin carryover

Answer

The CLSI order of draw is: blood cultures, light blue (citrate), red/serum, green (heparin), lavender (EDTA), gray. By drawing the green heparin tube before the light blue tube, heparin can carry over on the needle into the citrate tube and falsely prolong PT/aPTT results. Blood cultures are drawn first (not last) to preserve sterility, and the culture cannot be contaminated by a tube drawn after it.

Question 5

A 24-hour urine collection for creatinine clearance is started at 7:00 AM Monday. Which patient action during the collection invalidates the specimen?

Accepted Answer

Voiding at 6:50 AM Tuesday, discarding it, and ending the collection

Answer

In a 24-hour collection, the first void at the start time is discarded (that urine was formed before the window began), all subsequent urine is collected, and the final void at the end of the 24-hour period MUST be included because it represents urine produced during the window. Discarding the last void — even one 10 minutes before the end time — under-collects the total volume and falsely lowers a clearance calculation. Refrigeration between voids is correct handling for most 24-hour tests.

CCMA - Certified Clinical Medical Assistant Practice Test

CCMA - Certified Clinical Medical Assistant Practice Test

CCMA Laboratory Procedures 5