Endocrine Testing LabMed 5

Endocrine Testing LabMed 5. بسم الله الرحمن الرحيم.

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Control of Thyroid Hormone Synthesis and Secretion.

A 30-year -old female attended her GP. She had drastic weight loss over three months; was irritable; and felt uncomfortable in hot weather .she was taking estrogen containing oral CP. On examination here palm were sweaty, and she had fine tremors. She had no thyroid enlargement . What were the lab tests ordered?.

The GP ordered thyroid function tests(FT3 ; FT4 ; TSH ).

the diagnosis in this patient is T3 toxicosis based on increased plasma FT3 and very law TSH in the presence of Normal T4 Since the patient was thyrotoxic without goiter thyroid scan was made which showed diffuse and increase uptake of Tc-99m A request was made for assays of thyroid stimulating immunoglobulins (TSI) =thyroid receptor antibody.

111. CASE SCENARIO 1.

Follow-Up The TSI level was found to be 122% (reference range, 0% to 130%), The patient had Grave ’ s disease, but no goiter TSI stimulate thyroid hormone synthesis but not thyroid growth.

TSH T 3 T 4 Thyroid status Very law Hight or normal High High High High Primary Hyperthyroidism Secondary hyperthyroidism High Law Low Law Low Law Primary Hypothyroidism Secondary hypothyroidism law N N Subclinical hyperthyroidism high N N Subclinical hypothyroidism.

Variables affecting T3; T4 and TSH testing: 1-Hospitalized patient and recovery from illness(ESS)=NTI 2-Pediatric and neonate 3-Pregnancy 4-drug treatment 5-Assay interference 6- Reference range 7-follow up test selection.

1-Hospitalized patient and recovery from illness(ESS)=.

2-Pediatric and neonate Neonatal thyroxine levels are generally elevated at birth when compared to adults, such as 11.8 to 22.6 _g/dL for ages 1 to 3 days, due to maternal estrogen induced thyroid-binding globulin (TBG) levels. It is likely that thyroxine levels may occasionally fall below normal reference ranges due to inadequate protein feeding or prematurity rather than congenital hypothyroidism . Thyroxine levels gradually decline to the adult reference range by age 10, with some fluctuations in the values at onset of puberty. Free thyroxine is generally near adult levels but generally is tested only after repeat thyroxine levels and TSH are determined to be abnormal..

Thyroid – Part 1 – Thyroid Function Test (Thyroid Hormones) T4, T3, TSH – Labpedia.net.

Lithium, tricyclic antidepressants and selective serotonin reuptake inhibitors (SSRIs), antiepileptics, rifampin and metformin, mainly affect directly thyroid function. The antiarrhythmic drug Amiodarone (iodine containing) can induce thyroid dysfunction Interferon- α and antiretroviral drugs may have several effects, including inducing thyroid autoimmunity..

5-Assay interference : Some patient have heterophil antibody that react with animal Ig in vitro which may give false normal or elevated TSH in some thyrotoxic patient. Patients with ant-T4,anti-T3 and Anti-TSH antibodies can also interfere with the assay. Sampling: Serum sample For newborn: filter paper blotting 6- Reference range Must be age related and trimester related in pregnancy.

Serum T3, T4 can be used to follow the treatment with thyroid dysfunction Measurement of plasma TSH is not a reliable guide for thyroid status during the first 4 to 6 months of treatment in hyperthyroidism (TSH still be suppressed).

ADRENAL GLAND Adrenal gland Medulla Blood vessels Kidney Capsule Cortex.

Adrenal Gland Hormones and Interpretation, Blood sample and Precautions – Labpedia.net.

'10222 a, SW' SS. Time of day, month or year may affect lab test results.

Some tests must be collected at specific times or days in order to provide meaningful clinical information. Examples: Hormone level measurements may be significantly impacted by time of day or day of month Blood counts, electrolytes have minimal diurnal variation Therapeutic drug monitoring is often linked with timing of drug administration.

Case Scenario 2. A 46-year-old man has poorly controlled diabetes mellitus type 2 and HTN presents to establish care with a new physician. A third-year medical student performs a history and physical Ex. The student notes that the patient has a “moon-shaped” face, centripetal obesity, prominent violaceous abdominal striae and multiple scattered ecchymoses. Do the described findings warrant a workup for any additional disease process? Yes , Cushing Syndrome is in the differential diagnosis..

Case Scenario 2. As part of the diagnostic evaluation a salivary cortisol level is ordered . At which time of the day should this specimen be collected? A. Early morning B. Mid-day C. Early evening D. Late evening E. In two successive days or in the same day Discuss your rationale:.

Cortisol levels fluctuate as does ACTH throughout the day Levels peak in the early morning Levels are lowest in the late evening around bedtime Patients with Cushing syndrome have elevated late night salivary (as well as serum) cortisol values Sample for cortisol must be collected at 8:00 a.m. and then collect a second sample in the same day at 8:00 p.m..

Age Gender Race Exercise Diet Posture Stress (venipuncture ) Genetic predisposition.

The preliminary diagnosis for patient was dehydration The laboratory technologist was asked to help collect blood samples from this patient , Who appeared weak and not very responsive while the laboratory technologist performed the phlebotomy technique She noticed that he had a darker tan under the arms, spots on the forehead, and dark lips . What are the lab tests to be ordered in this case.

The laboratory results were as follows: Test Patient Reference Range Na ( mmol /L) 129 136–145 K ( mmol /L) 5.2 3.5–5.1 Cl – ( mmol /L) 98 98–107 HCO3– (mmol/L) 21 22–28 Anion gap ( mmol /L) 10 5–10 Glucose (mg/ dL ) 49 74–100 What are hormones will most likely be the next step for laboratory testing in this individual?.

The results indicate hypoglycemia, hyponatremia, and hyperkalemia . The physician ordered cortisol , and aldosterone tests next. Cortisol 0800 hr was 3 u g / dL (reference range, 5 to 23 u g / dL ) and 2000 hr was 2 u g / dL (3 to 16 u g / dL ). Aldosterone 0800 hr (supine) was 2 mg/ dL (3 to 16 mg/ dL ). These results indicate adrenal insufficiency and correlate with the symptoms of weakness, hypoglycemia, electrolyte imbalance, and dehydration..

The plasma ACTH levels were elevated, indicating primary adrenal insufficiency. A dose of 0.25 mg of synacthen (synthetic ACTH) was given and timed collection of plasma for cortisol was obtained at before and 30 minutes after dosage. The serum cortisol levels remained well below 7 u g/dL, confirming adrenal insufficiency..

Other Variables affecting cortisol and ACTH testing : Emotional stress , estrogens containing oral contraceptive Steroid therapy ( stopped within 12 h before ) If not possible, dexamethasone not prednisolone should be prescribed (not cross react with cortisol assay ).

Methods of hormone assay. Sampling: Time of sample collection: Cortisol and ACTH :morning (8 – 10 am) and evening (10-12 pm) because of daily circadian rhythm. Sex hormones and gonadotrophin hormones monthly circadian rhythm in female Blood collection: Most hormones are stable in aspirated blood sample which is collected in dry tube and serum is separated after blood clotting. Insulin separated immediately and kept in fridge Renin ; gastrin and ACTH and PTH are aspirated into EDTA tube and plasma is separated immediately by centrifugation twice to avoid proteolysis and kept frozen till assayed..

Methods of hormone assay. Analytical Methods: 1-Competitive binding techniques: Where the hormone compete with labelled one for binding sites in vitro . The binding sites may be antibody ,binding proteins or receptor The labelling may be radioisotope ; enzymes or fluorochrome The techniques are radioimmunoassay (RIA); enzyme linked immunosorbent assay (ELISA) and Fluoro immunoassay (FIA) 2-Chromatography: This is a reference method.

Catecholamines testing.

Measurement of plasma catecholamines: this is a sensitive test that needs specialized equipment's. Measurement of urinary catecholamines metabolites: vanillyl mandelic acid (VMA) is the reliable test. In patients with paroxysmal attacks of hypertension basal measurements should be made once in between attacks, and another estimation, when the next attack occurs..

1-The diet excluded the following items: • Caffeine (found in coffee, tea, cocoa, and chocolate) • Amines (found in bananas, walnuts, avocados, fava beans, cheese, beer,and red wine) • Vanilla (in foods or fluids) • Licorice عرق سوس • Nicotine (4 hours before collection of urine and during the urine collection), alcohol (ethanol), and cocaine 2- these analytes are sensitive to drugs (azathioprine).

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