How To Fail A Testosterone Blood Test Forum

The showtime step (bated from identifying symptoms) in diagnosing testosterone deficiency, aka low-T, is to practice a blood test.

Hither I cover some important practical things to know about a claret draw for testosterone analysis...

Time of mean solar day - is it necessary to obtain morn values?

All fractions of testosterone in the blood, i.due east. total testosterone, free testosterone and bio-available testosterone, display a circadian rhythm. Highest levels are constitute in the morning and the lowest levels occur in the evening, with peak levels at approximately 08:00 h and nadir at approximately 20:00 h.[ane-half dozen]

In healthy males anile 26-45 years, levels of free testosterone and bio- testosterone in early morning samples (nigh 05:30 am) are significantly different from those taken before midnight.[2] The amplitude of the free testosterone rhythm (34%of basal) is greater than that for total testosterone (24% of basal).[2] Another study in men anile 30-40 yr found total testosterone levels to be 20-25% lower at 16:00 h than at 08:00 h.[1]

To consistently capture peak testosterone levels for evaluation, an early morning blood draw time generally has been accustomed as standard do, and clinical practice guidelines for diagnosing testosterone deficiency recommend measuring testosterone in forenoon blood samples taken betwixt vii-eleven am.[7, viii]

However, this recommendation has been challenged on the basis of a lack of consistent show that morning levels are more than accurate in diagnosing androgen deficiency than those measured in the afternoon. [ix] Crumbling is associated with a subtract in the diurnal variation of total testosterone levels [1, 5, 10-thirteen], even though in fit good for you men the diurnal rhythm can be maintained into the seventh decade of life. [4] The degree of this age-related blunting varies between studies. I report establish total testosterone levels to be x% lower at 16:00 h than at 08:00 h in men aged seventy yr [1], while another study demonstrated that the early morning rise in testosterone levels feature of young men is not nowadays in men aged 52 yr.[10]

Therefore, an early morning blood draw, which is unpractical for many patients, may exist unnecessary in many men over 45 yr. A contempo study confirmed that men older than age 45 years tin have their total testosterone drawn at whatsoever time before 2 pm without fear of misleading results.[15] Still, while an early morn claret draw may non be critical for capturing total testosterone levels in men 45 years or older, when measuring free testosterone or bio-available testosterone, an early morning draw fourth dimension around 8-x am may still be preferable for men aged up to 75 years.[14]

Food intake before blood depict - does it impact testosterone levels?

Potentially more important than the issue of morning vs. afternoon blood testing is the bear on of nutrient intake on acute fluctuations in testosterone levels. You may be wondering "Exercise I need to fast for a testosterone blood examination?" Several studies have investigated the testosterone response in men to meals of different caloric and macronutrient (carbohydrate, protein and fat) content. Depending on the repast composition, these studies demonstrated after-meal (postprandial) decreases in total testosterone ranging from fifteen% to 40%.[16-18] Fat rich meals may also lower free testosterone levels.[17, 18] This fifteen-40% drop in full testosterone levels afterward meal ingestion can easily obscure the 20-25% morning vs. afternoon difference.[1]

A high-fat test meal containing 1,300 kcal (eleven% carbohydrate, 3% protein, 86% fat) was shown to cause a significant reduction in total testosterone (-22%) and complimentary testosterone (-23%)  ane hour postal service-ingestion in healthy men [18]. This reduction remained significantly below baseline for 8 hours.[18] Carbohydrate intake (75 g glucose, 300 kcal) has been demonstrated to suppress full testosterone levels past 10% [xix], 14% [20] and 30% [21]. Intake of 75 g glucose resulted in a xv% reduction of fasting total younger men levels after thirty minutes in younger men, which connected for up to 3 hours.[xx]

Two recent studies specifically investigated the impact of an intake of 75 g glucose on total testosterone levels in healthy men of a wide historic period range, spanning nineteen-78 years and a BMI of twenty-39.[22, 23] It was found that glucose ingestion at 8:thirty am significantly lowered total testosterone levels, basal testosterone secretion rate, and total (basal + pulsatile) testosterone secretion rates compared with water ingestion at the same fourth dimension of day.[22] In the example of LH, pulsatile rather than basal secretion fell after glucose  intake. Testosterone and LH levels, as well equally basal testosterone and pulsatile LH secretion, declined proportionately. In particular, the initial 2-h decrement in testosterone levels was 86 (27–144) ng/dl per unit subtract in LH concentrations (IU/L). The testosterone secretory flare-up size (mass, ng/dl), manner (min),  and number (per 6.five h) did not alter, indicating that glucose selectively suppresses non-pulsatile (basal) testosterone secretion.[22] It was concluded that, barring a selective increase in the metabolic clearance rate of testosterone, glucose intake in men acutely suppresses pulsatile LH and basal testosterone secretion after an overnight fast.[22]

A similar written report by some other research group examined the impact of glucose intake on serum testosterone levels in men with varying glucose tolerance [23]. 74 men (xix-74 years, mean 51 years) underwent a standard 75 1000 oral glucose tolerance exam with claret sampling at 0, 30, 60, 90 and 120 min. Glucose ingestion caused a mean 25% decrease in total testosterone levels (121 +/- 9 ng/dL). The maximum decrease amounted to a whopping 47%! Testosterone levels remained suppressed at 120 min compared with baseline ([395 vs 476 ng/dl) and did not differ across glucose tolerance or BMI [23]. A similar pregnant drop was seen in complimentary testosterone. Importantly, of the 66 men with normal total testosterone levels at baseline, ten (15%) had levels that decreased to the hypogonadal range below 280ng/dL at one or more time points.

To engagement, no recommendations exist regarding testosterone measurement in relation to food intake. However, these findings raise an important issue with regard to the optimal atmospheric condition under which testosterone deficiency should be assessed in men. To obtain a accurate film of testosterone levels, men who present with signs and symptoms of testosterone deficiency and who display borderline non-fasting low serum testosterone levels, should accept morn measurements taken in a fasting state. Doing fasting blood draws is common practice for many routinely measured parameters (eastward.1000. glucose, lipids, etc.) so it would be wise to add together testosterone to that claret draw analysis.

Summary

For an authentic reading, men below 45 years should do blood work for testosterone analysis in the morning between 7-eleven am. The morning-afternoon difference can be as large every bit twenty-34% for the total testosterone reading. Nonetheless, because the circadian testosterone fluctuation decreases with age, men over 45 years can have the blood drawn at any time during the twenty-four hours.

A potentially more influential factor is that of food intake earlier the blood draw. A large meal an 60 minutes or two earlier doing a blood depict tin cause an acute 47% driblet in full testosterone levels. This tin hands obscure the 20-25% morning vs. afternoon deviation. Because of the large impact nutrient intake can have acutely on testosterone levels, men with normal full testosterone levels at baseline can easily get a hypogonadal reading in the one-2 or and so hours after having ingested a big meal.

If you want an accurate reading of your testosteonre status, these are important factors to bear in mind.

References:

one.            Brambilla, D.J., et al., The event of diurnal variation on clinical measurement of serum testosterone and other sex hormone levels in men. J Clin Endocrinol Metab, 2009. 94(3): p. 907-13.

2.            Cooke, R.R., J.E. McIntosh, and R.P. McIntosh, Circadian variation in serum costless and non-SHBG-bound testosterone in normal men: measurements, and simulation using a mass action model. Clin Endocrinol (Oxf), 1993. 39(two): p. 163-71.

three.            Montanini, V., et al., Age-related changes in plasma dehydroepiandrosterone sulphate, cortisol, testosterone and free testosterone cyclic rhythms in adult men. Horm Res, 1988. 29(1): p. 1-6.

four.            Diver, One thousand.J., et al., Diurnal rhythms of serum total, gratuitous and bioavailable testosterone and of SHBG in middle-aged men compared with those in young men. Clin Endocrinol (Oxf), 2003. 58(six): p. 710-7.

five.            Gupta, S.Grand., E.A. Lindemulder, and G. Sathyan, Modeling of cyclic testosterone in good for you men and hypogonadal men. J Clin Pharmacol, 2000. 40(vii): p. 731-8.

6.            Winters, Southward.J., Diurnal rhythm of testosterone and luteinizing hormone in hypogonadal men. J Androl, 1991. 12(3): p. 185-90.

7.            Bhasin, Due south., et al., Testosterone therapy in men with androgen deficiency syndromes: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab, 2010. 95(6): p. 2536-59.

8.            Wang, C., et al., Investigation, treatment, and monitoring of belatedly-onset hypogonadism in males: ISA, ISSAM, EAU, EAA, and ASA recommendations. J Androl, 2009. 30(1): p. 1-9.

9.            Morgentaler, A., Commentary: Guideline for male testosterone therapy: a clinician's perspective. J Clin Endocrinol Metab, 2007. 92(two): p. 416-7.

ten.          Bremner, West.J., M.V. Vitiello, and P.Northward. Prinz, Loss of circadian rhythmicity in blood testosterone levels with crumbling in normal men. J Clin Endocrinol Metab, 1983. 56(6): p. 1278-81.

11.          Plymate, S.R., J.S. Tenover, and West.J. Bremner, Circadian variation in testosterone, sex hormone-binding globulin, and calculated non-sex activity hormone-binding globulin bound testosterone in healthy young and elderly men. J Androl, 1989. 10(5): p. 366-71.

12.          Luboshitzky, R., Z. Shen-Orr, and P. Herer, Middle-aged men secrete less testosterone at night than young good for you men. J Clin Endocrinol Metab, 2003. 88(7): p. 3160-6.

13.          Collier, C.P., et al., The significance of biological variation in the diagnosis of testosterone deficiency, and consideration of the relevance of total, free and bioavailable testosterone determinations. J Urol, 2010. 183(vi): p. 2294-nine.

14.          Guay, A., G.Chiliad. Miller, and C.L. McWhirter, Does early morning versus late morning draw time influence apparent testosterone concentration in men anile > or =45 years? Data from the Hypogonadism In Males report. Int J Impot Res, 2008. twenty(2): p. 162-7.

fifteen.          Welliver, R.C., Jr., et al., Validity of Midday Full Testosterone Levels in Older Men with Erectile Dysfunction. J Urol, 2014.

xvi.          Habito, R.C. and Thou.J. Ball, Postprandial changes in sex hormones after meals of different limerick. Metabolism, 2001. l(5): p. 505-xi.

17.          Meikle, A.W., et al., Effects of a fat-containing meal on sex hormones in men. Metabolism, 1990. 39(ix): p. 943-6.

18.          Volek, J.Due south., et al., Effects of a high-fatty diet on postabsorptive and postprandial testosterone responses to a fat-rich repast. Metabolism, 2001. 50(eleven): p. 1351-5.

nineteen.          Hjalmarsen, A., et al., Sex hormone responses in healthy men and male person patients with chronic obstructive pulmonary disease during an oral glucose load. Scand J Clin Lab Invest, 1996. 56(7): p. 635-40.

20.          Jeibmann, A., et al., Glucagon-similar peptide-1 reduces the pulsatile component of testosterone secretion in salubrious males. Eur J Clin Invest, 2005. 35(9): p. 565-72.

21.          Wall, J.R., et al., Fall in plasma-testosterone levels in normal male subjects in response to an oral glucose load. Lancet, 1973. 1(7810): p. 967-viii.

22.          Iranmanesh, A., D. Lawson, and J.D. Veldhuis, Glucose ingestion acutely lowers pulsatile LH and basal testosterone secretion in men. Am J Physiol Endocrinol Metab, 2012. 302(6): p. E724-30.

23.          Caronia, L.Chiliad., et al., Abrupt decrease in serum testosterone levels after an oral glucose load in men: implications for screening for hypogonadism. Clin Endocrinol (Oxf), 2013. 78(2): p. 291-six.

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