Veterinary medical systems
Veterinary medical systems are very similar to human medical
systems. One of the biggest differences is that patients are animals
and clients are people who own the animals. This introduces some
interesting complications when it comes time to pay for the bills. The
system keeps track of what procedures and medicines were used on the
patient, but when it comes time to pay, the bill is sent to the
This would be straightforward, except in the area of
horses. Since racehorses are quite expensive, it is very common for a
single horse to be owned in various percentages by several
owners. This adds several interesting possibilities to handling the
billing. Often, each owner is responsible for their proportion of the
total bill. Each owner would like to receive a complete invoice with
his portion already calculated. However, if a horse is treated for a
condition that one owner considers to be "their fault" that owner may
pay for the entire procedure. As a third possibility, the owners may
divide up the bill along line items. One owner will pay for some of
the line items, while other owners are responsible for other line
Please remember that in a typical clinic <5% of all of the bills will
be this complicated with the single-owner patient being the most
common. The system should be design so that the common case is not too
slow or overly complicated.
Dave Atkins brings his pet Doberman named Fluffy into the clinic
for a routine examination and shots. The veterinarian charges him
for the routine office visit and the Rabies vaccination. Dave pays
cash before he leaves for the day and is provided with a receipt for
Traci Heinrich brings in both her cats, Tweedle Dee and Tweedle
Dum to be spayed. Dr. Roberts performs both spays (which has a
standard rate). Traci picks up her cats that evening, but wants to
be billed for the service. That day she receives a single invoice with
the itemized charges. At the end of the month, she receives a
statement for her account, which she pays.
The racehorse "Polymorphic Message Send" is owned by Grady Booch
(30%), Martin Fowler (20%), Ralph Johnson (20%), Erich Gamma (10%),
and Brian Foote (20%). The horse is beginning to show some signs of
lameness, so Ralph brings the horse in for an
examination. Dr. Roberts decides that it is not a matter of concern
and prescribes some topical analgesic. Ralph is provided with an
invoice itemizing the charges. The invoice also shows what
percentage of the charge each owner is responsible for. At the end
of the month, a statement is sent to Grady, Martin, Ralph, Erich
and Brian detailing the amount that they owe.
"Polymorphic Message Send," who is stabled on Ralph's ranch, gets
spooked by one of his grad students and runs through a fence
resulting in severe lacerations. Ralph calls Dr. Roberts who makes
an emergency farm call to suture up the lacerations. Ralph feels
responsible and wishes to pay the entire bill himself. At the end
of the month, only Ralph receives a statement which contains the
charges for the emergency call.
Ralph brings "Polymorphic Message Send" in for a routine checkup,
but he also brings his pet iguana, "Generational Scavenger", who
hasn't been eating well. Dr. Roberts examines both. Ralph gets an
invoice, which he pays, that day that includes his portion of the horse's bill and
the entirety of the iguana's charges. Later that month, the horse's
co-owners receive a statement with their portion of the charges.
Everytime a patient is brought into the clinic, if the patient has
been there before, Dr. Roberts looks up the patient's history on
the computer. This history includes every procedure that has been
performed on the patient along with any prescribed drugs.
When a client does not pay their bills in a timely fashion,
statements are issued each month. If the client continues
nonpayment, eventually their account is "written-off." If a client
that has been written-off brings a patient to the clinic, they will
not receive treatment until their outstanding is paid.
Some procedures need to recur at regular intervals (e.g. yearly
immunizations, checkups, monthly heartworm treatment). The system
should keep track of which patients require which treatments and
issue reminders that are mailed to their owners the month before
the treatment is due. When a patient is marked as deceased, such
reminders should cease.
In the preceding use-cases the following terminology is used:
Client: Dave Atkins, Traci Heinrich, Grady Booch, Martin Fowler, Ralph
Johnson, Erich Gamma, Brian Foote.
Patient: Fluffy, Tweedle Dee, Tweedle Dum, Polymorphic Message Send