Thank you for the reply Steve and the 10000 foot view
icd 10 is an international coding for desease, it can be linked to patient or to order(the reason why he is taking these tests). Sample tbl is nessary because one sample can have many orders (dapy). Sometimes (stat-emergency) i dont have a formal invoice (order) just a paper with patient name ,doctor, healthcare, and hand written tests... (looks like a shopping list...anyway..)Think sample number as the identity of the laboratory sample, It could be used as barcode number, the unique identification , directly linked with the patient. Ex from one botle of blood(sample) i can perform almost every biochemical test, the tests could be to many orders. If you see to analyzers and samples tbl, i have linked one type of sample to each analyzer. There are many collection tubes depending by the test. There are times which i have to collect 5 tubes (samples), to perform the ordered tests... like Count Dracula... lol Sample id is the same because the all are from the same patient.Why not use patient id? Because there could be a repetition the near or far future.