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[IP] Re A1c and Malingering
I read this on ) 2003 Medscape and thought the reference to the unusual A1c
especially interesting in view of the recent IP discussions on A1C . The
title of the posting was A Case of Malingering? I personally got a kick out
of the "no blood on the paper" with the log brought to the doctor. Gosh, I
always recopied my own logs because I was so ashamed of my messy notes. I
like the comment about "no patients with type 1 diabetes can maintain their
glucose values that stably for more than a few days". Duh! How many doctors
REALLY acknowledged this 40 odd years ago! Now why did it take ME 48 years to
stop feeling guilty about my own unstable bg, yes even with the pump? < grin>
I'm sure this article will trigger many memories for those of us who spent
years squirming through our diabetic checkups knowing that no one believed
anything we said anyways.
Type 1 48 years
I have a patient who has type 1 diabetes and, despite her excellent
control with multiple daily injections, her A1c remains very high: 17% to
18%. She has used an insulin pump, but the results didn't change. What
might be happening?
Giselle Safatle, MD
from John B. Buse, MD, PhD, 03/14/2003
This is a clinical situation that is a bit more extreme than the ones I
have seen, but similar patients have tended to display 1 of 2
characteristics. By far the most common is that they are malingering and
purposefully leading you and, often, their families astray. If they bring in
a glucose log, fairly common mistakes by patients include:
The same pen is used for weeks of records.
There is no blood on the paper.
There is not random distribution of the final numbers of the values.
(Often people fabricating logs have a digit preference and will have
more numbers ending in 0 or 3, for example.)
I think the best hint from a glucose log would be if the numbers are
high (over 200 mg/dL) and never low (under 70 mg/dL). Virtually no
patients with type 1 diabetes can maintain their glucose values that
stably for more than a few days, and even that would be quite unusual.
More often than not, malingerers will come up with a wide assortment of
excuses for why they forgot to bring in their logs. These behaviors can
best demonstrated by providing the patient with a meter with memory and
when the patient returns either scrolling back in the memory or
downloading the meter to determine how often the patient is checking and
what values are present. I have seen patients that have gone to the
extreme of using other people's blood, a pet's blood, or the
manufacturer's control solution to get good glucose values.
Another route of investigation is to really nail them down on how often
they test their blood glucose, how much insulin they take, and how often
they take it by finding out where they purchase their insulin and
and how much they get at one time. By calling the pharmacy, I have
occasionally been able to determine that the patient was not buying
enough insulin or testing strips
Finally, if you are unable to demonstrate malingering, we often have
patients spend the day in the office, where they eat their meals under
observation and are monitored frequently using our own equipment.
I have been flummoxed more than once by engaging patients for some time
this regard. I would be extremely suspicious in this setting, no matter
how unlikely you think the possibility of malingering is.
There is one other clinical situation that I have encountered, but on
one occasion. There are hemoglobinopathies that with certain A1c assays
read spuriously high. As an example, hemoglobin H and hemoglobin Old
Dominion/Burton-upon-Trent, among others, are associated with elevated
A1c. If this is the case, it may be possible to demonstrate that other
first-degree relatives exhibit this trait. As an example, a sibling,
parent, or child without diabetes may have an A1c much higher than
There have been reports of elevated hemoglobin F (persistent fetal
hemoglobin) co-eluting with hemoglobin A1c in an assay employing
ion-exchange elution. In such a case, using an A1c assay employing
affinity methods or ion capture immunoassays should not provide spurious
results. Hemoglobin electrophoresis may be of value for persistent fetal
hemoglobin, though most clinical labs do not screen for rare variants
as hemoglobin H. There are reports of certain assays being interfered
by elevated triglycerides and with hydroxyurea treatment.
A fructosamine value should not be affected by alteration in hemoglobin
structure and should be normal or near normal in the case of excellent
control. Various investigators have suggested that there are some people
who will more rapidly glycosylate proteins nonenzymatically. I think
would be unheard of to cause the degree of elevation of A1c that you
describe. Furthermore, repeatedly measuring urine glucose at an office
visit should occasionally produce glycosuria in someone with an A1c that
John Buse, MD, PhD, Associate Professor of Medicine, Director of the
Diabetes Care Center, University of North Carolina, Chapel Hill, North
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