Fig. 4. Temperature changes during the frozen proficiency test materials delivery. (A) The delivery box was arrived about 27 hours later, and the temperature inside of delivery box was maintained under –20℃. (B–D) The delivery boxes were arrived between 38 to 42 hours later, and the temperatures were maintained between –68.1℃ and –20.6℃ (→: arrival time).
© Lab Med Qual Assur
