Laboratory Tests in Older Adults:
Indications, Interpretation, Issues
27
T.S. Dharmarajan and C.S. Pitchumoni
Questions and Answers
1. A 75-year-old male in good health is being evaluated for
elective hernia repair. He is not on any medications. In
addition to the history and examination, you wish to order
laboratory tests. Which one of the following choices
would be the most appropriate choice in this setting?
A.Hemoglobin, hematocrit, glucose, creatinine, blood
urea nitrogen (BUN), electrolytes
B.Hemoglobin, hematocrit, glucose, creatinine, BUN,
electrolytes,
prothrombin
time,
International
Normalized Ratio (INR), and liver function
C.Hemoglobin, hematocrit, creatinine, glucose, BUN,
electrolytes, prothrombin time, INR, and prostatespecific antigen
D.Hemoglobin, hematocrit, creatinine, HbA1c, BUN,
electrolytes, and urinalysis
Answer: A
Ordering a large number of tests does not improve the
safety of the surgical procedure; the best choice would be
to base test selection on the history and examination. In
this case, the patient is in good health, further substantiated by the fact that he is not on medications; the choice
here would be to obtain the minimal tests required to
ascertain the absence of common problems in older
adults. Obtaining bleeding and clotting tests would be
dependent on a history of bleeding, clotting or liver disease, and medication history (anticoagulants, aspirin,
NSAIDs). Prostate-specific antigen has no role prior to
surgery and in fact requires a discussion regarding its
risks and benefits with the patient prior to being ordered.
Urinalysis has no routine role prior to surgery outside the
urinary tract. Random glucose levels and the history
should provide suspicion for diabetes, rather than obtaining a HbA1c screen at this stage.
2. In order to minimize legal concerns, which one of the following strategies is most helpful?
A.Order the number of tests indicated, tailored to history
and examination; review and initial the results, and
take action for those values where indicated
B.The more the tests ordered, the lower is the risk. The
odds are you are likely to have covered apparent and
nonapparent illness
C.When the results are available, have the office staff
review them and place the results in the chart
D.Review the laboratory results and attempt to memorize
the general picture; at the next patient visit, document the
abnormal results along with visit
Answer: A
Is there an increase in liability for requesting or not
requesting a test?
Legal concerns are one reason for providers to request
routine laboratory tests. Although there may be legal risk
for failure to order a test and make a diagnosis in the first
place, the risk may be even greater for ordering a laboratory test and not following up in a timely fashion with
required actions based on the abnormal results. Laboratory
test results must be acknowledged, and reports initialed
by the provider. Documentation must include both negative and positive findings; critical test results warrant
immediate action and rapid communication to the patient,
along with ­documentation and actions taken. In summary,
it is most desirable that the provider who orders a test follows up with the test results quickly and appropriately.
3. Regarding hemoglobin and hematocrit testing in the geriatric population, which one of the following statements is
not true?
A.Anemia is common in the older age group; hemoglobin testing is an inexpensive and simple option to detect
anemia, although it does not delineate an etiology
C.S. Pitchumoni and T.S. Dharmarajan (eds.), Geriatric Gastroenterology,
DOI 10.1007/978-1-4419-1623-5_27, © Springer Science+Business Media, LLC 2012
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B.The etiology of anemia cannot be determined in nearly
two-thirds of cases by routine testing for hemoglobin,
and assays for transferrin saturation and ferritin, B12
and folic acid, and kidney function
C.In two-thirds of patients with anemia, a diagnosis is
readily discernible by basic tests, while the remaining
third requiring further complex testing to determine an
etiology
D.Nutritional anemia accounts for anemia in a third of
older adults based on National Health and Nutritional
Examination Survey (NHANES) data, and anemia of
chronic disease (including CKD) accounts for another
third. The rest have “anemia where the etiology is not
clear”
Answer: D
Anemia is a common multifactorial condition in the geriatric age group. Based on the WHO definition, anemia is
present in 10% of the over 65 year group and 20% of the
over 85 years group in community older adults, increasing to about 50% in nursing home residents. Based on the
NHANES data, two-thirds of anemia have a discernible
cause with routine or basic testing. A third have a nutritional basis involving iron, B12, and folic acid deficiency
alone or in combination, while a third has anemia of
chronic disease. In a third routine, tests do not provide a
ready explanation and need more sophisticated testing for
conditions such as myelodysplastic syndrome or myeloma.
Anemia is a marker for illness and seldom the result of
aging. Age by itself cannot account for anemia in the
majority. The impact of anemia on organ dysfunction
cannot be underestimated; it is an additional negative
component for outcomes in heart disease, diabetes, and
cerebrovascular disease and a predictor of mortality, justifying testing for hemoglobin in older adults. The association between anemia and gastrointestinal disorders is
common and well known.
4. Seventy-year-old woman with atrial fibrillation comes to
you with echymoses over his extremities and bleeding on
brushing the gums. He is on warfarin. Laboratory testing
reveals hemoglobin to be 10 g/dL and the INR of 4.0 (target 2.5). All of the following considerations would
account for the increase in INR, except:
A.Possible excessive consumption of alcohol with impact
on liver function; testing is indicated for liver function,
platelet counts, and folic acid assay
B.An enquiry on herbs and supplements intake is indicated;
consideration includes ginger, garlic, and ginkgo biloba
C.The high INR is an error; repeat testing is the next
step prior to any actions, as the value was at target a
month ago
D.The patient may have begun to consume grapefruit
juice recently
T.S. Dharmarajan and C.S. Pitchumoni
Answer: D
Warfarin is an anticoagulant known to be associated
with adverse effects, arising in large part due to drug–
drug or drug–disease interactions. Herbals are well
known to cause bleeding through interaction with warfarin; ginger, garlic, ginkgo biloba, and saw palmetto
increase the INR, while ginseng lowers the INR.
Grapefruit juice inhibits the CYP system in the gut but
does not impact warfarin pharmacokinetics. In general,
routine repeat testing of critical values of hemoglobin,
platelet count, white blood cell count, prothrombin time
or INR and activated partial thromboplastin time do not
offer advantage over a single run; while one may repeat
the test, any action for a critical value is best taken
immediately. In this case the INR of 4 is already associated with bleeding and taken in context is cause and
effect. Alcohol consumption (whether apparent or not)
is a consideration with unexplained abnormal liver function tests (LFTs) or with other signs such as unexplained
macrocytosis.
5. Regarding LFTs, which one of the following is not true?
A.LFTs are a panel of tests and not true tests of liver
function; abnormalites may reflect disease
B.Medication-induced abnormalities are extremely common in the geriatric population
C.Abnormal liver function in an asymptomatic patient is
uncommon; when they occur an exhaustive evaluation is
indicated
D.Nonalcoholic fatty liver disease may be the most common cause of abnormal liver function, especially in the
affluent society
Answer: C
LFTs include a panel of tests, but per se are not reflective
of liver function; included are liver enzymes, bilirubin,
and hepatic synthetic measures (prothrombin time and
albumin). About 1–4% of asymptomatic patients manifest
abnormal tests, with results influenced by a host of factors, including gender, ethnicity, illness (e.g., metabolic
syndrome, nonalcoholic fatty liver disease), medications,
over-the-counter drugs and supplements, and alcohol.
Nonalcoholic fatty liver disease is a common cause of
abnormal AST and ALT worldwide, especially in affluent
nations, increasing with the growing obesity epidemic. A
focused history and physical examination are a foundation for appropriate testing. The value of serum albumin
levels is immense; levels reflect not only nutritional status, but also relate to renal and hepatic function. Abnormal
LFTs are commonly encountered in asymptomatic
patients during routine visits; a cost-effective and systematic approach is recommended for their interpretation,
with consultations in select cases.