updated 21 September 2008 at 6:12 pm
Reference Values for Laboratory Tests
The Merck Manual of Diagnosis and Therapy :an excellent on-line source in two versions
Healthcare Professions Edition (more complete, more detailed)
Home Edition for Patients and Caregivers (easier to read, less detailed)
NIH Medline Plus
Resources from Wofford's Sandor Tezlor Library
Thomas L. a 28-year-old male, complained of abrupt polydipsia and polyuria. Blood and urine analyses provided the following results:
Water deprivation and hypertonic saline infusion do not cause a significant reduction in the polyuria and concentration of urine. Complete water-deprivation results in the following: Urine osmolality 225 mOsm/L. However, there is a significant concentration of the urine and a decrease in urinary output following administration of ADH.
1. Define polydipsia and polyuria.
2. Why did the water deprivation and hypertonic saline infusion not result in a concentrated urine?
3. Describe the location of the disorder in Thomas L.
4. Thomas L. was given a nasal spray containing a synthetic substance to self-administer to treat this condition. What type of compound was present in the nasal spray?
5. Diagram the hypothalamic-pituitary-target organ pathway for this individual and indicate the normal and pathophysiological conditions involved.
6. What is the long-term prognosis for Thomas L?
Hazel C. a 30-year-old female demonstrated a subtle onset of the following symptoms: dull facial expression; droopy eyelids; puffiness of the face and periorbital swelling; sparse, dry hair; dry, scaly skin; evidence of intellectual impairment; lethargy; a change of personality; bradycardia (60 b/min); a blood pressure of 90/70; constipation, and hypothermia. Plasma concentrations of total and free T4 and T3 follow:
3 ug/dL (normal = 4-12 ug/dL)
0.14 ng/dL (normal = 75-195 ng/dL)
Radioimmunoassay (RIA) of peripheral blood indicated elevated TSH levels. A TSH stimulation test did not increase the output of thyroid hormones from the thyroid gland.
1. Why does Hazel have a lower-than-normal body temperature?
2. What is a TSH stimulation test and how are the results interpreted?
3. Is this a primary or secondary disorder? How is this determined?
4. Describe the feedback loop involved,. Predict whether you'd expect TSH levels to be normal, high, or low?
5. What is the most likely diagnosis for Hazel?
6. Would you expect to find a palpable goiter? Explain your answer.
7. What is the most likely explanation for the bradycardia and low blood pressure? Constipation?
8. Describe a suitable treatment for Hazel. Would this treatment require injections or capsules?
9. Is this treatment expected to return blood pressure and heart rate to normal? Why or why not?
Oscar T. a 45-year-old male from the Midwest presented with the following symptoms during February: weakness, fatigue, orthostatic hypotension, weight loss, dehydration, and decreased cold tolerance. His blood chemistry values follow:
Hematology tests resulted in the following values: Hematocrit 50%; Leukocytes 5000/cu mm
Oscar also noticed increased pigmentation (tanning) of both exposed and nonexposed portions of the body and back. A plasma cortisol determination indicated a low cortisol level. Following administration of ACTH, plasma cortisol did not rise significantly after sixty and ninety minutes. Endogenous circulating levels of ACTH were later determined to be significantly elevated.
1. What endocrine organ is the site of the malfunction? . Is this a primary or secondary disturbance?
2. What is the name of this disorder?
3. Discuss the electrolyte (Na+ and K+) disturbances resulting from this disorder. Which hormone is involved and are the levels of this hormone abnormally high or abnormally low?
4. Discuss the metabolic disturbances resulting from this disorder. Which hormone is responsible?
5. What is the cause of Oscar's tanning?
6. What type of replacement therapy would be required for Oscar?
7. Diagram the feedback loop for this endocrine disorder.
8. What is the long-term outlook for Oscar? Might one expect Oscar's abnormal pigmentation to resolve? Explain.
A 50-year-old male (Horace C.) had a total thyroidectomy followed by thyroid hormone-replacement therapy. Thirty-six hours later he developed laryngeal spasms, a mild tetany, and cramps in the muscles of the hands and arms. The following tests were performed:
Calcium gluconate and vitamin D (calcitriol) were given orally each day and
the tetany and laryngeal spasms were alleviated.
(Your textbook will prove particularly useful in this case.)
1. What endocrine disorder is present in Horace?
2. What is the purpose of vitamin D administration with the calcium?
3. What caused Horace's tetany and laryngeal spasms?
4. How is blood calcium normally maintained at its physiological level?
5. Diagram the negative feedback loop for the hormone(s) involved.
6. Is hormone replacement therapy necessary for Horace or could his case be managed by nutritional supplements?
A 21-year-old noncompliant male with a history of type I (insulin-dependent) diabetes mellitus was found in a coma. His blood glucose was high, as well as his urine glucose, urine ketones, and serum ketones. His serum bicarbonate was <12 mEq/L. His respiration was exaggerated and his breath had an acetone odor. His blood pressure was 90/60 and his pulse weak and rapid (120).
1. Define noncompliant.
2. Is this person experiencing ketoacidosis or insulin shock? Explain your answer.
3. Why is the serum bicarbonate low?
4. What is the acid-base status of this individual?
5. What is the cause of the dyspnea, hypotension, and tachycardia?
6. What type of treatment does this person need?
A 59 year-old female complains of numbness of the hands, excessive sweating, and an unpleasant body odor. She also remarked that she has gone up a ring size and shoe size. Upon examination, she presents with the following symptoms: thick, oily skin; skin tags; impaired vision; headaches, fatigue, and weakness; and menstrual cycle abnormalities and breast discharge. Evaluation of a blood sample revealed the following levels:
GH level (ng/ml)
GHRH level (µg/mL)
IGF-1 level (ng/ml)
Blood pressure (mm Hg)
125 to 460
1. What endocrine organ is involved? How does one determine which it is?
2. What is the name of this disorder?
3. What is an explanation for the patient's high blood pressure?
4. Give an explanation for the patient's breast discharge and unpleasant body odor?
Based on the site of the disorder, what might the nature of the visual impairment be?
5. What could be a possible cause for the development of this disorder?
6. Diagram the negative feedback loop for the hormones involved.
7. What is a possible treatment for this disorder?
A thirty-five year old female visited her gynecologist early one morning and complained of the following symptoms: fatigue, depression, unexplained weight gain, and an irregular menstrual cycle. Her doctor ordered a series of tests to determine the cause of her symptoms. The following were reported:
· Serum Human Chorionic Gonadotropin Test: Negative
· Fasting Blood Glucose: 65 mg/dL
· Serum Cortisol: 28 mg/dL
· Leukocytes (WBC): 6,500 cu mm
· Hematocrit: 43%
The doctor reviewed her results and asked her to return to repeat the test the next afternoon. The results were nearly identical. Next, a dexamethasone test was ordered for the following morning and revealed that her cortisol level had decreased to 10 mg/dL.
1) What endocrine gland(s) is/are the site of malfunction?
2) What is the name of this disorder?
3) What are the possible causes of this disorder?
4) Is there a diurnal cycle for levels of cortisol in a healthy individual?
Does this patient have a normal diurnal cycle?
5) What is a dexamethasone suppression test? Why was it ordered for this patient?
How are the results of this test interpreted?
6) What does the dexamethasone suppression test reveal as to the site of endocrine
disorder in this patient?
7) What other tests could be done to determine the exact cause of the malfunction of this endocrine gland?
8) What are the possible treatments for an individual with this disorder?
9) What is the long term outlook for this patient?
Susie B., a three and a half-year-old female, is brought to the hospital by her parents who are concerned about her slow growth, night sweats, and craniofacial abnormalities. Blood analyses provided the following results:
- Fasting Glucose: 42 mg/dL
- Serum sodium: 140 mmol/L
- 8am Cortisol: 28 mg/dL
- Fasting GH: 9 ng/dL
- IGH-1: 12 ng/dL
Upon observation, craniofacial abnormalities include protruding forehead, small
(double) chin, delayed teething, sparse hair. Slow motor development was also
She was unresponsive to growth hormone therapy treatments. Normalization of growth was observed with IGH-1 therapy.
1. What types of cells are abnormal in this patient? How do you know?
2. What could be a possible cause of high GH and cortisol levels?
3. What is a possible explanation for retarded growth in the presence of high GH levels?
4. Describe the feedback loop involved.
5. What is the most likely diagnosis for Susie?
6. Why did treatment with IGH-1 work for Susie, while GH therapy did not?
7. What's the prognosis for Susie with AND without IGH-1 treatment?
Essentials of Metabolic Diseases and Endocrinology. Bacchus, Habeeb
Ph.D., M.D., F.A.A.P. University Park Press, 1976.
The Pharmacological Basis of Therapeutics, Tenth Edition. Joel Hardman,
Lee Limbird, Alfred Gilman. McGraw Hill Co. Inc. 2001.
Ref RM 300.G644 2001
Endocrine Physiology. Hardy, Richard N. University Park Press, 1981.
Endocrinology: Biological and Medical Perspectives. Paxton, Mary Jean
W. Wm. C. Brown Publishers, 1986.
QP 187.P34 1986
Textbook of Medical Physiology, Tenth Edition. Guyton, Arthur C. MD.,
Hall John E. Ph. D. W.B. Saunders Co. 2000
Ref QP 34.5.G9 2000
Hormones: From Molecules to Disease. Etienne-Emile Baulieu, Paul A.
Kelly. Hermann, 1990.
QP 187.H595 1990