Medical Assistant Lab Values Cheat Sheet

Spirometry requires both acceptability and reproducibility. Current guidelines state that the two largest FVC values must be within 0.150 liters of each other. Because the variance is over 0.200 liters, the results are not reproducible, and the assistant must perform additional maneuvers (up to a maximum of eight) until the values fall within acceptable limits. Option A is incorrect because spirometry relies on the highest values, never an average. Option B is unnecessary as calibration is a daily pre-test requirement, not a mid-test correction for patient variability. Option D is incorrect because accepting a single high value without reproducibility violates quality standards.

Puncturing perpendicular to the fingerprint whorls ensures the blood forms a distinct, round drop rather than running down the natural grooves of the patient's finger. You must also always wipe away the first drop of blood with dry gauze. This initial drop contains interstitial fluid and residual alcohol, which can dilute the sample and cause inaccurate glucose readings. Collecting the first drop or cutting parallel to the whorls will compromise both the collection process and the test results.

When applying a pediatric urine collection bag, the medical assistant must ensure the perineal area is completely dry after cleansing. Option B is correct because moisture prevents adhesion, causing the bag to leak or detach before a sufficient sample is collected. Option A is incorrect because barrier creams leave a greasy residue that completely inhibits the adhesive from sticking to the infant's skin. Option C is incorrect and potentially harmful; surgical tape can cause skin tears on delicate infant skin and is not the standard method for securing these bags. Option D is incorrect because a warm compress does not aid in adhesion and could potentially irritate the skin or compromise the adhesive material. Achieving a clean, dry surface is the most critical step for a successful pediatric urine collection.