คำตอบ: D · It is a screening test, so a diagnostic test is offered to confirm it
เหตุผลที่เป็นคำตอบนี้
Cell-free DNA testing analyses placental DNA in the mother's blood. It is very accurate but remains a screening test, so a high-chance result is confirmed by chorionic villus sampling or amniocentesis.
คำตอบ
D · It is a screening test, so a diagnostic test is offered to confirm it
3.การคำนวณขนาดยา
คำตอบ: V = 10 mL
Solution strengths: a percentage strength is grams per 100 mL, so 1% = 1 g/100 mL = 10 mg/mL. A ratio strength 1:1000 means 1 g in 1000 mL = 1 mg/mL; 1:10 000 is 0.1 mg/mL. For a dilution the amount of drug stays the same: C₁·V₁ = C₂·V₂.
Body-surface-area dosing: many cytotoxic and some paediatric doses are prescribed per square metre of body surface area: dose (mg) = dose per m² × BSA (m²). The Mosteller formula estimates BSA = √(height (cm) × weight (kg)/3600).
พื้นที่ผิวร่างกาย
BSA = √(110·19/3600) = √0.5806 = 0.7619 m²
ขนาดยา
D = 135·0.7619 = 102.9 mg
คำตอบ
D = 102.9 mg
5.อัตราการให้สารน้ำทางหลอดเลือดดำ
คำตอบ: V = 600 mL
Infusion rates: a pump is set in mL/h = volume/time in hours. A gravity drip is counted in drops per minute: gtt/min = volume (mL) × drop factor (gtt/mL)/time (min). The drop factor is printed on the tubing package: macrodrip sets deliver 10, 15 or 20 gtt/mL (blood sets often 10 gtt/mL in the US, 15 in the UK) and microdrip sets 60 gtt/mL. Always use the drop factor the question or package gives.