CNA CNA Medical Lab and Specimen Collection Skills

Question 1

When collecting a clean-catch midstream urine specimen, what is the correct sequence of steps?

Accepted Answer

Void first portion, collect midstream, then finish voiding into toilet

Answer

A clean-catch midstream urine specimen requires the patient to void the first portion into the toilet, collect the midstream urine into the cup, and then finish voiding into the toilet. This technique minimizes contamination from skin flora around the urethral opening.

Question 2

A patient requires a 24-hour urine collection. What should the CNA do at the START of the collection period?

Accepted Answer

Discard the patient's first voiding, then begin collecting all subsequent voidings

Answer

To begin a 24-hour urine collection, the patient voids and that first specimen is discarded. The collection clock starts at that point, and ALL subsequent urine for the next 24 hours is collected. This ensures a complete 24-hour measurement.

Question 3

When collecting a urine specimen from a patient with an indwelling Foley catheter, where should the CNA obtain the sample?

Accepted Answer

From the drainage port on the catheter tubing using a sterile syringe

Answer

Urine specimens from Foley catheters must be obtained from the designated sampling port on the catheter tubing using a sterile syringe and needle or needleless system. The drainage bag contains old, potentially contaminated urine and should never be used for specimens.

Question 4

A patient needs a stool specimen for occult blood testing. What food should the patient avoid before this test?

Accepted Answer

Red meat, raw vegetables, and aspirin

Answer

Before a fecal occult blood test (FOBT), patients should avoid red meat (contains blood), certain raw vegetables like radishes and turnips, vitamin C supplements, and aspirin/NSAIDs that can irritate the GI tract and cause false positives or negatives.

Question 5

When collecting a stool specimen, how much stool is typically required?

Accepted Answer

About the size of a walnut (1-2 tablespoons)

Answer

For most stool specimens, a walnut-sized amount (approximately 1-2 tablespoons) is sufficient. The exact amount may vary by test type, but this is the general guideline. For FOBT cards, a small smear from two different parts of the stool is used.

CNA Practice Test

CNA Practice Test

CNA CNA Medical Lab and Specimen Collection Skills